STOREHOUSES.
The latest form of storehouses tends to one of two extremes. Where land is nearly level, and cheap, the greatest storage capacity can be obtained with the greatest economy by means of a one or two story storehouse built with a plank construction, with the beams secured to the posts by means of knees. A traveling crane or railroad runs along the middle of the storehouse, affording a ready means for rapid changes of the contents of the storehouse.
Another form for storage is by means of very large brick buildings, especially arranged as a protection against outside fire. In designing a storehouse it is of especial importance that the stories should not be made so high that it will be possible for a dangerous load to be piled upon any one floor.
The wool storehouse of the Pacific Mills at Lawrence can be safely said to be in its design and construction the finest example of mill engineering in the country.
Another type of mill storehouse, designed for both raw material and finished goods, is designed by Mr. John Kilburn, of Lowell, and consists of two buildings
placed at right angles to each other, and joining only at one corner. These buildings do not contain openings through the floors of any nature whatsoever, either for stairways, elevators, or any other purpose; but all vertical communication is furnished by means of a masonry tower at one corner of the buildings, which contains an elevator and stairway. At the level of each floor, substantial balconies lead through a doorway in the tower to one in the storehouse, and the storage is added to or withdrawn from the storehouse in this manner.
I have not made any reference to the use of rolled iron for structural purposes, because such material has not been used to any extent in mill architecture. Irrespective of questions of space or of strength, wood beams possess advantages in the reduction of vibration, facility of securing the plank above and hangers below, and a great many other purposes in the changing and alterations of a mill, which render them peculiarly useful, and I believe that the results with Southern pine beams in American mills are much superior to those of the iron beams in European mills.
No small part of the success attending the use of rolled iron in the structural purposes for which it is adapted, has been due to the excellent and reliable engineering information contained in the manuals and catalogues issued by the rolling mills. Such works are reliable and clear, and, as far as I know, can without exception be safely followed.
The general tendency of American mill construction is toward as low buildings as the price of land will admit. The American mills being devoted to a large variety of operations, instead of being confined to a single process after the manner of those of European type, require a great deal more care in their organization, not merely in the original lay-out for the purpose of arranging for the passage of the stock in processes from the raw material to the finished product in as straight lines as possible, but due consideration should also be given to providing facilities for the enlargement of the mill.
As an illustration of the methods employed, in a paper mill plan of my own design, [the view and plan being thrown on the screen], the various operations containing processes of different hazard in regard to fire are completely isolated from each other by means of fire walls, and the storage of the mill is in turn isolated from the manufactory.
The storehouse consists of three sections, the largest section for paper stock, which is sorted in the upper story, the second section, one story in height, for other manufacturing supplies, and beyond the fire wall the storehouse is arranged to contain the finished paper. Goods can be taken away from or added to the storehouse at the single line of teams, or railroad siding.
After the stock leaves the sorting room, it is carried to the dusting room over a covered bridge, which is protected from the weather on one side, yet does not form a flue for the spread of fire as does a closed bridge.
The first room in the main mill is used for a dusting room, and thence the stock falls into the rotary bleach, whence it is carried through the fire doors to the engine room. Here it meets the wood pulp and clay wheeled from the middle section of the storehouse, which is on that same level. After washing and beating, the stock is run into the drainers below, whence it is raised again, and after suitable intermediate processes the pulp is converted into paper on the paper machine in the connecting building. This paper is then taken into the upper part of the main building, and after being dried on the lofts is suitably calendered and packed before being transferred into the extreme end of the storehouse to await shipment.
At the present time it has been found that an inclined roof of the olden type is not a necessity over a paper machine, as has been decreed by the tradition passed down from old practices. Within the last year, a number of flat roofs have been placed over paper machines, without any trouble ensuing from condensed water forming on the ceiling and thence dropping upon the stock. It is well known that the use of a flat roof in such places is attended with a great many mechanical conveniences; and the pitched roof hitherto used for these purposes has been submitted to, only because it was presumed to be necessary. The whole tendency of mill design is in the line of fitness of means to ends, in the simplest and most direct manner.
When the mills in Lowell were first built, they consisted of isolated buildings, which it was presumed would remain for all time; but when it became necessary to increase the plant, it was found that the engineer had wisely laid out the mills in the same yard in reference to a fixed grade, so that corresponding floors would meet when the buildings were extended so that they reached each other.
Wherever a strong and diffused light is necessary for any manufacturing process, or the conditions are such as to require unusual stability of the building, one-story mills lighted by monitors afford accommodations not reached by any other form of construction.
In presenting before you some of the salient features of modern mill construction, I have endeavored to show the various steps of progress leading up to the development of the present types of design, as well as some of the methods of construction in present use.
These various steps in advance, producing mills better suited for the purposes for which a mill is built, are not generally due to elements originating with the manufacturers, but with the Factory Mutual Underwriters, who, finding it cheaper to prevent a fire than to settle a loss, have in every manner encouraged improvements in construction, equipment, and administration, with the result of diminishing the insurance on textile manufacturing property during the last generation from two and one-half down to one-fourth of one per cent., or reducing the cost of insurance eighty per cent.
In designing any work, a careful regard should be given to precedents, remembering that a good designer must also be a good copyist.
[The Passive State of Iron and Nickel.]—E. Saint Edme.—The nickel of commerce immediately becomes passive if immersed in ordinary nitric acid. Iron, while being briskly attacked by common nitric acid, is rendered passive by contact with nickel. If steel and nickel are plunged into the acid together, the former metal is not even momentarily attacked. Nickel retains energetically a proportion of combined nitrogen, to which its passivity is due.
IMPROVED TORPEDO BOAT.
We give an illustration of the new type of second class torpedo boat which Messrs. Yarrow & Co. have recently constructed to the order of the Admiralty, and which was tried at the latter part of last year. The boat is 60 ft. long over all and 8 ft. 6 in. wide, 3 ft. shorter and from a foot to 15 in. wider than the old type of second class boats. She attained a speed of rather more than 17 knots per hour on her official trial with 4 tons on board. The speed, when light, for six runs on the measured mile was 18½ knots. The latter seems a very high speed for so small a vessel, and indeed it is a remarkable performance, but at the same time the speed of 17.031 knots on a four hours' trial with 4 tons on board is more remarkable still. It is well to note, says Engineering, in comparing speeds of torpedo boats, under what conditions as to weight carried and duration of running the trial is made. In our previous notice we referred to the manner in which this boat differs from ordinary second class boats in the manner of ejecting the torpedo; and the arrangement is well shown in the engraving. The more ordinary method of firing the torpedo from a tube or tubes, built into the hull and pointing forward through the bow, will be familiar to the majority of our readers; but here it will be seen the bow fire has been altogether abandoned, and a swiveling gun placed aft is substituted. The gun, of course, is not new; indeed, one was placed on the old Lightning, the first torpedo boat built for the English navy. That vessel was, however, a first class boat, and although not so large as the first class boats now built, was considerably bigger than No. 50, which is the official designation of the craft under notice. In the Lightning, too, the torpedo gun was placed forward, and was trained in quite a different manner to that of this second class boat. We have already commented on the offensive advantages of being able to eject the torpedo through a wide angle of range, and when going at speed, rather than having to bring the boat to a stop and fire only end on. We need not therefore recur to this point; but since our former notice appeared we have had, while on shore, an opportunity of seeing the boat steam at speed and maneuver. Our previous experience was obtained on board—a position which, in some respects, does not afford so good a point of observation as when one is at some little distance from the boat. It is certainly a remarkable sight to see the manner in which this little vessel winds among craft or round buoys, or turns circles of surprisingly small diameter. She seems to pivot on a point very near the bow, a fact which is no doubt chiefly to be accounted for by the way the deadwood is cut away aft. This allows the stream of water diverted by the unusually large rudder to swing the after part round with facility.
IMPROVED TORPEDO BOAT.
Another notable feature about No. 50 is the comparatively small bow wave she throws up. We believe it is pretty generally acknowledged now that the most noticeable point at night about a torpedo boat traveling at high speed—putting on one side flame and sparks from the funnel—is the high bow wave the majority of these vessels throw up when going quickly through the water. The powerful electric search light causes this mass of foaming water to show up with peculiar distinctness against the dark background of sea and sky. It has been, therefore, thought advisable to reduce this undesirable feature even if something in the shape of speed has to be sacrificed. Fairly full bow lines are the best for fast boats of this class, but in such a model the big bow wave is very noticeable. Messrs. Yarrow have met the demand of naval officers for a less easily observed boat by placing the greatest cross section further aft than they would have done had speed alone been the point aimed at, as it almost always was in the earlier torpedo boats. It is therefore additionally creditable to Messrs. Yarrow that they have reached the unprecedentedly high speed of seventeen knots, with so considerable an addition to the beam, and that they have at the same time reduced the bow wave.
There is a further advantage of less surface disturbance when running torpedo boats. It is unnecessary to point out that surprise will be the chief element of success in future possible attacks in which these craft may be engaged. As the bow wave is most likely to reveal the presence of the boat by sight, so also will it most probably give first warning of approach by sound. It is the splash of the water and not the noise of the machinery that can be heard for the greatest distance when a boat is running with hatches closed—speaking of course of high-speed boats in which the engines are
kept to a high degree of perfection, as they should be, and in the Royal Navy are, with all torpedo boats. It will therefore be seen that there is an additional reason for reducing the objectionable bow wave.
The boat which we illustrate recently made the run from the Thames to Portsmouth, and, the weather being bad, was taken through the somewhat intricate but more sheltered fairways and channels of what is known as the "overland passage." Off Margate she managed to get on the ground—a result by no means to be wondered at; and, as the sands here are very hard, she smashed her propeller. After a time she was got off and beached, when a new propeller was fitted. We mention this incident, as it is generally supposed that these craft are of a very fragile description; "egg shell" is the favorite term of comparison. One distinguished naval officer—retired—has said he would never willingly go on board these craft, for fear of putting his foot through the bottom; and there is a very funny story extant about a sailor with a wooden leg. It would seem, however, from the experience of No. 50, that steel vessels are of much more robust constitution than is generally supposed, and, indeed, there is ample testimony to the fact. We recently witnessed the efforts of a small working party to get one of these vessels over a bank. She was pushed as high up as the strength of the party would allow, and in this position her fore part was over the bank for about a third of the length of the boat. A tackle was then put on the bow, which was bowsed down until the boat could be dragged straight ahead.
A few words may appropriately be added here as to torpedo boat policy generally. Admiral Colomb, in the opening remarks of his excellent little manual, "The Naval Year Book," refers to the torpedo boat question in the following terms: "The fleet, the flotilla, the cruiser, and the harbor attack and defense have each had (i. e., during the past year) their share of attention, and developed exercise, and opinion has been advanced, guided, or turned back by the observation of facts which these exercises have brought out. While it cannot, perhaps, be said that the torpedo, as torpedo, has much altered its position in naval estimation, it seems fair to assume that the torpedo boat, as boat, has fallen in repute. In the first, it has grown very much larger, and has, in point of fact, ceased to be a boat. In part this may have come about because the role which some proposed for the torpedo boat, of being an entirely defensive weapon confined to territorial localities, and operating only within a short distance from its port, has never been generally accepted. Boats which were never intended for voyages have been sent on voyages, and, being found more or less unsuited for that kind of service, supposed improvements have been made, so that they should be capable of executing it. The 'harbor defense' instrument has become a 'sea attack' instrument, and in some sense an unrecognized rival to the undoubted sea-going torpedo vessels like the Archer, the Fearless, and the Rattlesnake."
In these passages Admiral Colomb has put the present aspect of the torpedo boat question very aptly. We are now experiencing the inevitable reaction consequent upon our early over-valuing of the torpedo. The unknown possibilities for distinction of those weapons were so magnified that scarcely any expenditure was thought too great to provide means for their employment, both in and out of season. Torpedo vessels have been growing in size and costliness. More and more gear has been crowded into them, increasing their weight and cost, and also the intricacy of their machinery. In all this, cheapness, the one great virtue of the torpedo, has been overshadowed. No doubt it is right for a great naval power like Great Britain to have vessels of all classes, and the possible value of small fast vessels such as the Archer or the Rattlesnake—not necessarily as connected with the torpedo—can hardly be overestimated. But for smaller naval powers, that look on the torpedo boat as a means of coast defense, especially those countries having a broken coast line studded with islands, bays, and inlets, it is very questionable whether the smaller boats, such as that now under notice, will not be a better investment than the larger craft at present more in vogue. By the additional seaworthiness of this boat, secured chiefly by the increased width, the 60 ft., or second class, boat has been lifted into the category of practicable vessels; and it must be remembered that four or five of these smaller craft can be purchased for the price of one modern first class boat. This is the crucial point, the money standard, and it is to that that all ship and boat building questions must be reduced,
whether it be in wealthy England or the most impecunious and perhaps hardly more than half-civilized state.
The question may be argued from many points of view, and we put forward these remarks simply as suggestions, without any wish to dogmatize. But it seems that, as the cheaper second class boat has been carried so many steps in advance, it may be worth while to reconsider the position with a view to returning to the original torpedo boat idea of small, inexpensive vessels, acting by surprise; and not putting too many eggs in one basket.
SCIENTIFIC APPARATUS AT THE MANCHESTER ROYAL JUBILEE EXHIBITION.
Sine and Tangent Galvanometer.—An exhibit of original scientific apparatus was contributed by Prof. G. F. Fitzgerald, of Trinity College, Dublin. The first instrument was a sine and tangent galvanometer, which combines both instruments, and has four interesting peculiarities: (1) The windings of the coils are visible through the plate glass sides, so as to be capable of easy measurement in situ. (2) The position of the needle is read by reflections of a cylindrical scale in two rectangular mirrors whose intersection is horizontal, and which are attached to the magnet. These mirrors reflect images of opposite sides of the scale to a fixed mirror which reflects them into a microscope, in which, by means of a micrometer, it is possible to read accurately the position of the line which is the same in the two images. (3) This cylindrical scale is affixed to the base of the instrument, and the coils can be rotated round it, so that when the instrument is used as a sine galvanometer its position is read by reflection in the rectangular mirrors attached to the magnet of a pointer attached to the coils. (4) By a slight modification of the suspension, a beam of light can be reflected from a mirror connected to the magnet at 45° to its axis of rotation, and can emerge through the plate glass side of the instrument and fall on a horizontal scale, where it will measure the tangent of the deviation instead of the tangent of twice the deviation, as in ordinary reflecting galvanometers.
The meldometer shown is an instrument for facilitating the identification of small quantities of minerals by comparative observations on their melting points, and for observing the phenomena of their fusion and ebullition. It consists of a strip of platinum arranged to traverse the stage of a microscope, and heated by a current derived from two Grove's cells.
On this strip the fragments of the mineral, or, if for comparative observation, of two or more minerals, are placed. The temperature of the platinum is then raised by gradually diminishing a resistance placed in circuit with the battery and meldometer, the behavior of the substance being meanwhile observed through the microscope. To effect the elevation of a temperature automatically, a resistance, consisting of a rod of carbon fitted in a vertical glass tube, is employed. Professor Fitzgerald showed two sets of apparatus for measuring the densities of gases. Both methods depend on the determination of the amount by which a body is buoyed up when immersed in the gas.
Model for Illustrating the Properties of the Ether.—A very interesting exhibit was the model for illustrating the electromagnetic and luminiferous properties of the ether, of which a detailed description is almost necessary. The model consists of a series of wheels, rotating on axes fixed perpendicularly in a plane board, and connected together by India-rubber bands. The axes are fixed at the intersections of two systems of perpendicular lines, and each wheel is connected with each of its four neighbors by an India-rubber band. Thus all the wheels can rotate without any consequent straining of the system if they all rotate at the same rate. If, however, some of the wheels are rotated through a different angle from others, the India-rubber bands will be strained. If it be desired to represent a region in which conducting matter exists, it will be represented by removing the bands from a set of wheels. Suppose the bands are removed from the regions, A and B, and from the connecting line, A B, then we can represent the charging of these regions with opposite electricities by introducing some mechanism by means of which the wheels on opposite sides of the line, A B, can be rotated in opposite directions. The model is not intended to illustrate in any way the connection between the ether and matter; indeed, one of the advantages claimed for the model is, that the study of it so distinctly emphasizes the distinction between the phenomena depending on the general properties of the ether by itself and
those depending on its connection with matter. For instance, from the very case we have just considered, we get impressed upon us that it is by means of matter only that we can get a hold on the ether so as to strain it. As the object is not to illustrate the connection between matter and ether, any rough method of turning the wheels so as to create the proper strain will do well enough, as it is not the method of producing, but the nature of the strain produced that is to be considered. Having once rotated these wheels, we may replace the bands along the line, A B, and we have the state of the ether between two oppositely electrified bodies represented on the model.
It will be observed that half the India-rubber bands are strained, and that in lines running round the bodies the tight side of a band is always away from one body and next the other. This represents the polarization of the ether. The late Prof. Clerk-Maxwell defined polarization as a state in which the opposite sides of each element are in opposite states. Now, the opposite sides of each band are in opposite states—one side loose, the other tight; and so it can very well represent the polarized state of the ether. The displacement producing the polarization is due to the different rotation of the wheels carrying the band causing more of the band to be at one side of the wheels than at the other—less at the tight and more at the loose side of the pair of wheels, and this represents the electric displacement producing the polarization. The direction of this displacement is at right angles to the line of the bands that are strained, and is out from one body and in toward the other all round.
Considering the other properties of the ether that are represented by the model, we observe in the first place that during the time polarization is taking place the wheels are rotating, and that the rate of rotation of the wheels is proportional to the rate of increase of polarization, and that the direction of the axis of rotation is perpendicular to the direction of the displacement. Hence it is seen that the magnetic force is properly represented by the rate of rotation of the wheels, and its direction by the axis of rotation. The model, although simple in construction, is very useful, and its careful study will greatly assist the student in obtaining definite physical conceptions of many of the more abstruse phenomena depending on the ether.
Prismatic Photometers.—Another exhibit was a photometer made of solid paraffin, or any other translucent substance, invented by Mr. J. Joly, of the University of Dublin. The arrangement is at once simple and effective. The instrument depends upon the fact that if a prism be cut from a translucent body, and so exposed to a source of light that one only of its faces is illuminated, the light diffused through the substance and reflected out through the illuminated faces of the prism gives it an appearance as if lighted up internally. The effect is, in fact, as if the prism itself was a source of light. Two such prisms laid together on smooth faces, and receiving light from separate sources, if placed so as to be at opposite sides of the plane of division, appear as if each was emitting light proportional in intensity to the source of its supply. The double prism has the appearance of two luminous bodies laid side by side.
When, however, the supply to each prism is brought to equality, they appear as if emitting equal quantities of light; and it is hard to detect any longer that two prisms are being observed, so completely does all trace of the plane of division disappear. An ingenious piece of apparatus invented by Mr. Joly was one for carrying out his method of determining the specific gravity of small quantities of dense or porous bodies. The method here shown enables the specific gravity to be determined whatever the density or state of aggregation of the substances, and in extremely minute quantities, with an accuracy limited only by the sensitiveness of the chemical balance.
Telegraphing the Readings of Scientific Instruments.—Another invention of Mr. Joly was his apparatus for obtaining telegraphically the readings of meteorological instruments placed at a distance from the observer. This apparatus may be attached or adapted to the various thermometers, the barometer, rain gauge, and to other instruments placed in a mountain station, thus enabling their readings to be taken from a conveniently placed observatory. Any number of instruments may be worked with perfect reliability and certainty by the use of three wires only; the only extra piece of apparatus needed being a disk, carrying insulated contact pieces arranged round its circumference, to which the wires of the different instruments are attached. Of these three wires, one serves to put one after the other of the contacts into circuit with the home station through the second wire. By this second wire the readings are taken and the readjustment of the instruments effected. The third wire is for the indication of the contacts, and is taken from all the instruments to the galvanometer in the home station.—Industries.
COLORED PHOTOGRAPHY.
About nine months since we directed attention to the system of colored photography invented by Mr. J. E. Mayall, London. Since that time, Mr. Mayall has further developed the details of his process, and as a result his color pictures have been much improved both as regards appearance and size, and are beautiful specimens of this new departure in photographic art. As stated in our previous notice, Mr. Mayall, after fourteen years of experimental research, has discovered the art of reproducing the colors latent in the negative of the photograph, having arrived at his discovery by the aid of spectrum analysis, which led him to the conclusion that every color in the organic world, when exposed to a suitable photographic plane in a camera, registers exact vibrations. Mr. Mayall has succeeded in producing chemical colors extremely attenuated, which exactly correspond with the vibrations in the negative. In doing this, he keeps the film alive to the smallest vibrations of light. He uses, first, lactate of iron to impregnate the isinglass film with a salt of iron capable of uniting with any stronger organic acid; and, secondly, meconic acid, which impregnates the film of albumen, and has a stronger affinity for iron than lactic acid. It unites with the iron, and forms a red film, which is in a state to receive all the lower vibrations of the red end of the spectrum, and this gives these lower vibrations a fair chance with the electric light. All subsequent processes assist this chemical march to the
final end of making a print that will take up colors, which, when added, fall in their places, and there remain indelible and unalterable.—Iron.
FUTURE PROSPECTS FOR GAS COMPANIES.[4]
By Mr. Thos. Wood, of Sandusky.
Those who were in attendance at our Dayton meeting will perhaps recall the fact that the writer, in a paper read at that time, strongly advocated gas companies taking hold of the electric light business and running the same in connection with their gas business; you will also recall the fact that the writer suggested that gas companies should take up the incandescent electric light and fuel gas. Since that time it has been demonstrated by several gas companies in this and other States that the electric arc system can be added with success, financially, to gas companies and with satisfaction to their patrons; and the writer derives great pleasure in hearing of so many companies who have left the narrow and beaten track of prejudice and are now walking in the broad road of progression.
[4] A paper read lately before the Ohio Gas Light Association.
It is not my intention to dwell upon arc lighting now only long enough to state that, after two years of practical experience with the combination, our company consider they have taken a right step in adopting it, and that it is satisfactory in every respect. Other gas companies that have adopted the arc system can undoubtedly corroborate this with their experience. I would make this paper a continuation of the last one by now taking up the incandescent electric system and fuel gas question. That both will be introduced into every city in the United States before long by some one I have not a shadow of a doubt; and why? Simply because they are both desirable commodities in domestic economy and hygiene.
Please lay aside all prejudice, and I will show you an ideal domestic burner for illumination purposes. Now, what comprises an ideal burner for domestic use? In the first place, such a burner must not blacken our walls and ceilings, neither must it give off deleterious products of combustion; it must be a steady light, and not subject to draughts; it must not give out heat in summer, it must not be possible for inflammable goods to ignite by coming in contact with it; it must be a light that will have no ill effect if by accident the key is left open; it must be a light that our country cousins cannot blow out, neither must it be one that requires dangerous matches to ignite it, and lastly, it must be a fairly cheap light.
Now, gentlemen, if you have thrown prejudice to the winds, perhaps you can recognize in this ideal burner the incandescent electric light for domestic use. Now, if this light is an ideal one, who is going to prevent its adoption by the public? Gas companies cannot, and if they cannot no one can. So, in my mind, the wisest course to pursue is to admit what we know to be true, and proceed at once to supply the demand, increase our revenue, push out into the suburbs of our cities, sell it as cheaply as possible, and don't let others come in and take away what rightly belongs to you. If there is any money to be made in the business by others, there is still more in it for us.
For store purposes, where the hours of burning are defined, I think it better to abandon the meter system and fix a price per annum or month for each lamp, taking into consideration the hours of use as a basis for charges. For private dwellings this would not be practicable, and we would have to resort in this case to meters, or perhaps fix upon a price for furnishing the current and have the consumer purchase the bulbs or lamps whenever renewals were necessary. In this way economy would cheapen the light to the consumer. Any method that will dispense with the meter and still be satisfactory will be the one to adopt.
I cannot understand how some gas companies who have the incandescent electric system as a competitor can console themselves with the fact that it is not injurious to their gas business, even taking it for granted they are selling as much gas as before its advent. Is this a just reason why they should make no effort to secure their old patronage? I think not, for it is human nature to secure a whole loaf in place of the half, when it is possible to get it. A gas company's revenues would certainly be increased by the step, and a dangerous rival would be made profitable.
I think it is a mistake to think that by and by the people will get back to gas. Of course some will, just as gas consumers sometimes go back to coal oil; but, because a few give it up, don't let us deceive ourselves by thinking that all will do it eventually, for the incandescent electric burner is bound to remain wherever it is now in use, and will find its way to the other places where it is not now in use. "That is all very well to talk about," I hear some one say, "but what are they going to do with our prior investment?" To such I would say, push that, too. Cheapen it to its lowest point and urge its use for power and cook stoves until such time that you find yourselves able to supply gas for heating purposes of all kinds.
What difference does it make to a company whether the money expended for improvement account be coal gas benches, holders and mains, or dynamos, boilers, and wire? I fail to see the difference, and if improvements have to be made in both, so much the better—it shows a healthy demand for both branches, and should be promptly provided for.
If arc lighting is to be the light on our streets and the incandescent electric light for our stores and dwellings, shall we have to draw our fires from under our gas benches and stop making gas? This, to the writer, would be an absurd deduction, for the very reason that in nature's laboratory all these elements are placed, and gas would not be one of them if there were not some important part for it to play in the supplying of man's wants. It is for us to take the things we find in nature's laboratory and select the fittest articles for each special use; and it is reasonable to suppose that it will be only the fittest that will finally be a success. The arc light, so far as the writer has ascertained, has asserted pretty generally throughout the country its supremacy on our streets, and this in spite of all opposition from gas companies—showing conclusively that it has gained its position by the force of demand for the fittest. Incandescent electric light is just as surely finding its position and field of usefulness, and in its turn will assert its supremacy, and why? Because it has the
qualifications called for in the public specifications. Some will assert that it is too expensive to come into general use, and also that it is not as reliable as gas. The first is no argument against it, for was not coal gas sold at exorbitant prices in its early days? It certainly is capable of being cheapened in the future, as gas has been, and this is one reason why gas companies should enter the business, as it is in their power to cheapen it.
As far as unreliability is concerned, it certainly looks the most serious objection; but don't be alarmed on that score, for duplicate machinery or storage batteries will eventually overcome this bugbear, and while discussing this subject don't let us forget that the breaking of a main, the filling up of a drip, a flood or explosion, or even Jack Frost, has often caused our customers to think that even gas is not very reliable.
I cannot understand what prompts gas companies as a rule to prejudice against electric lighting, unless it be they imagine the outcome to be idle gas mains and cold benches. This I think is all wrong. The largest unoccupied field to-day is the fuel gas field, and who should step in and supply this demand? Could any one do it as well as the present gas companies? We have our mains and services already laid; we have our holders, meters, and trained labor, most of us have also the necessary land to spare on which to erect the generators.
Next to the fuel gas field I think I can see another field nearly as extensive, and that is the coal oil field.
Please imagine the following picture, which is representative of the writer's belief of what a gas company will be in the near future; in fact so near in the future that before our next convention rolls around it will be a reality.
One set of officers, whose principal qualifications shall be progressiveness—their duties to be divided between electric lighting of all kinds, including electric power, fuel gas for all purposes, including gas engines; also incandescent lights off fuel gas mains.
Now let us see what the plant will consist of. One set of mains for fuel gas, from which our patrons will draw all their fuel, and also light, if they wish. Gas engines will be run economically with this gas. One set of meters only will be required.
There will be no coal gas benches as we have them now, as the method of manufacture is too laborious, too expensive and very primitive, not to say barbarous—everything now being built on the horizontal plan, requiring the greatest possible exertion to both draw a charge and stoke. The generators of the future will be on the cupola style, feeding by gravitation from the top. Native coals in all probability will be sufficiently good to make gas of. One portion of the plant will be devoted to the dynamos and engines for furnishing the electric light. Where the coal gas benches now are will be boilers, or perhaps even these will be unnecessary if gas engines be used. If steam boilers be used, they will be fired with producer gas, and the holders will become simply pressure regulators. The revenues of gas companies will be increased fivefold, if not more; the consumer will get cheaper fuel, cheaper power, and cheaper light.
Native coal fields will become more valuable, and we will not pay tribute to other States, as heretofore. The change from illuminating coal gas to fuel gas will perhaps be a slow one, owing to the conservatism of gas companies and imperfected details; but eventually it will be brought about in spite of all obstacles. If a company is operated as pictured, it will furnish arc lighting, incandescent electric lighting, and electric motors, fuel gas, incandescent gas lighting, and gas engines.
Gas will be made on a larger scale, with less dirt and nuisance, and without that laboriousness now made necessary. Valves, levers, and push buttons will displace scoop, drawing hook, and wheelbarrow, and the employees will no longer be known as "gas house terriers," but will become elevated to a higher plane. The officers of the company will also of necessity have to be more active and alert, and the rule of thumb will be at a discount. Now let us see where the gas man will be who fails to occupy these new fields of pasture green.
He will, of course, go on making coal gas in the old way; he will still wrestle with stopped stand pipes, steam jet exhausters, naphthaline, etc., and worry over how much a bushel of coke weighs. He will try to convince his customers that he knows better than they do what they want, and that anything but his gas is of no account. He will keep on cutting out items from the newspapers whenever he finds it recorded that an electric light somewhere failed to flicker.
He will still maintain that there is not a company in the country making anything out of electric lighting, and that it is only a matter of time when some fellow slips into his town and, noting things, works up an arc light company, captures the street lighting and some of our friend's best consumers. The price of gas is lowered; all kinds of patent gas burners are invested in to recapture those lost consumers; a fight ensues, factions are made in the town, and the arc light company adds an incandescent plant to the arc light, and captures more of our friend's consumers. To cap the climax, another fellow comes along and proposes to supply fuel gas to the citizens, gets a franchise, puts in pipes and services, and our friend wakes up some fine morning to find that what the electric light fellow has left him in the shape of lighting has been captured by the fellow with the fuel gas plant, who puts in the incandescent gas burners.
Evidence is cropping up all around us that tends to this change. We find manufacturers of fireclay goods now making carbons for electric lighting; we also find gas fixture manufacturers now making and selling electric wires of all kinds, besides other apparatus connected with the electrical field. Manufacturers of meters have not yet devised a meter for measuring electrical currents, but perhaps it would pay them to devote a portion of their time to studying one out. As far as the present meter business is concerned, I think, if this transformation of the gas business is brought about, the demand for gas meters would be quadrupled and the use of the larger sizes of meters would be made necessary; but if accuracy could be insured with a much smaller meter with quicker action, I think it would be better adapted for the purpose. Fuel gas, if it can be manufactured at a price at which it could be sold with profit at a lower or as low price as coal, would prove a larger field than all the kinds of lighting put together, and is certainly worth our while to
investigate thoroughly. The owners of the smallest houses of our cities would become our patrons, and a small profit per thousand would represent a wide margin when taking into consideration the large amount that would be consumed.
But is the fuel gas practical, and has there been sufficient progress made to date to warrant gas companies taking hold of it with any assurance of success?
In the first place, what assurance do we require? Do we want some one to come along and guarantee us a profit of 20 per cent. on our investment if we enter the field? If so, the patentees of the different processes might just as well negotiate with the shoe maker as with the gas company. I think all the assurance we want in the premises is that with certain apparatus we can get certain results from a ton of coal (the kind of coal being specified), or that from a ton of coal we can get a certain amount of available deliverable heat units.
The balance we should be capable of working out ourselves, such as labor, leakage, cost of gas at consumers' meters, and such other data that we certainly should be more familiar with than any one else.
Of course, the fuel gas will have to have an odor, and must be delivered at a proper pressure; and proper appliances for governing supply and insuring perfect safety will have to be calculated on. In fact, the gas man must try to improve on methods adopted, and do his best to hasten the day when solid fuel in our homes shall be no more—in other words, we have to take hold of the fuel gas business in its infancy or it will get weaned away from us.
Mr. McMillin, with others, has given us some figures on fuel gas which have been verified by practical tests. For instance, he gives us as his opinion that a mixed gas is more adapted for all-round purposes than either coal or water gas alone.
From experiments made we find that from a ton of bituminous coal, making a mixed gas, we can realize as salable gas 63 or 64 per cent. of the total heat units in the original ton of coal, or about 17,000,000 heat units, besides a residue of heat sufficient to produce the steam for making the above amount.
Of this mixture 20 per cent. is coal gas, made in the ordinary way, which is the only objectionable feature the writer can see in the process. I am inclined to think that Mr. McMillin rather strained a point here in order not to alarm coal gas men, or else to avoid a too radical change in the apparatus now in vogue for making coal gas.
By his statement we find that in water gas, labor and repairs cost but 7 cents per M, while coal gas costs for the same items 15 cents per M. Of course, the proportion of coal gas made by the old method is of more value in heat units than the water gas made by the new method; but what I wished to suggest was this, that if the whole process be made in the cupola as water gas is now made, whether the result would be the same number, or nearly so, of heat units in amount of gas made, with a large reduction in labor making the coal gas cost no more than the water gas for the item of labor repairs. If the mixture can be made in this manner, and I have some assurance that it can be done successfully, then I think it would pay any company to abandon the use of the present style of gas benches, and use the space now occupied by them with more improved apparatus, rather than use them at a loss, simply because we have them on hand.
We have pictured an ideal burner for our homes in the fore part of this paper, and I cannot refrain from holding up to your view this ideal fuel, which has no smoke, no dirt, no ashes, and entails on the housewife no extra labor, can be regulated automatically to one steady temperature, and does not require a workingman, after doing a hard day's work, to come home and find a ton of coal dumped on the front sidewalk, which has to be wheeled or carried in before night comes on.
Now that we have seen an ideal street light, an ideal house light, and an ideal fuel, we will endeavor to show you an ideal gas company; and we cannot do it in a more concise way than to say that an ideal gas company is one that keeps all these ideal commodities for sale at a reasonable price.
This may look visionary on my part to some of you, perhaps all of you; but, nevertheless, I feel that this is the place and time to talk over "our future prospects," and if this paper is the cause of any one investigating the subjects spoken of or bringing forth discussion regarding the same, I shall feel I have not written in vain.
THE APPLICATION OF ELECTRICITY TO LIGHTING AND WORKING.[5]
By W. H. Preece, F.R.S.
LECTURE I.
I appear before you to give a short course of two lectures on the application of electricity to lighting and working. To-night I shall confine my attention entirely to lighting, and if we succeed in getting through our subject, we shall devote ourselves next Wednesday to the application of electricity for working tramways, to the transmission of power for various purposes, and generally to working.
[5] Two juvenile lectures recently delivered before the Society of Arts, London.—From the Journal of the Society.
Many people imagine the electric light to be a cold light. It is a delusion. It is called a cold light because in many of its forms it gives what we may call a cheerless light; it has not got the warmth, the comfortable look, of other artificial means of illumination.
The electric light owes its existence to the intense heat that the electric current produces, and heat lies at the root of every system of artificial illumination. For instance, suppose we take a common match and light it, we light it simply because by the friction of the two surfaces together we generate heat, the heat burns the substance of which the match is made. We are able to light a common candle because we have applied heat to the wick, the heat liquefies the wax of which the candle is made, the wax is decomposed, it combines with the oxygen of the air, intense heat is produced at that point, carbon is consumed, and the consequence is light. So with all our various modes of artificial illumination. Gas, as you are well aware, produces intense heat, and the result of that heat is light. There are various ways
in which gas is applied to produce heat and the necessary consequence—light. Here is a Sellon gas burner, in which the combustion of gas raises the temperature of a fine platinum cap, and the result is, as you see, a very beautiful light. In one lamp we have a cap or mantle, in the other case there is merely a flat disk gauze of platinum. The combustion of the gas produces intense heat, which raises the network to a very high state of temperature, though in the present case the light is not so good as it should be, probably through the pressure in the supply main not being sufficiently great.
In another case we have a gas jet surrounded with a network of some vegetable matter, linen or cambric, steeped in a solution of salts of zirconium, and a few other rare earths, and the intense heat of the gas causes a very high temperature, and, as you see, a very brilliant effect is produced.
You will see from this that in all cases of artificial illumination bodies have to be raised to a high state of temperature. I hold in my hand a piece of magnesium wire; it is really flat magnesium tape, but it is called wire. If I heat that, you will observe that a very brilliant light is produced, due to the very high temperature at which it burns. Now, if I take a lump of coal and heat it—it requires to be raised to a certain temperature before the oxygen is directed upon it—and subject it to a jet of oxygen, you will see that it burns with very much more intense light than you are accustomed to in the ordinary fire. If I take a piece of iron wire and place it in a jar of oxygen, you see what a very brilliant effect the combination of oxygen and iron produces through the iron being raised to a very high temperature.
I have now shown you that in order to produce light we must, by some means or other, raise the temperature of a body. But the high temperature that we have to deal with is not that produced by the combination of the oxygen of the air and carbon, and other bodies such as I have shown you, but it is produced by the aid of the electric current. In all these cases the result of the combustion you have seen has been to remove oxygen from the air, but now I want to show you how a body can be raised to a high state of temperature without combustion of any kind. In front of me I have a fine platinum wire. In my hand I hold a wire that is in connection with a battery upstairs, the other wire in connection with the battery is attached to the far end of the fine platinum wire; now, when I make contact with the near end of the platinum wire, you observe that the wire is raised to redness, its temperature is high, and as I reduce the length of the platinum wire it gets brighter and brighter, the amount of electricity passing through it is greater and greater, and presently the wire is fused. I should have pointed out that as the quantity of heat generated in a wire increases, so does the color of the light. When heat is applied to a body, that body is first warmed, then it gets gradually hotter and hotter, until it becomes red hot, and the first color that appears is always red. The temperature is further raised, and the body assumes the color of orange, then at a little higher temperature it appears yellow, and so the different colors of the rainbow are perceived according to the different temperatures to which the body tested with is raised. Now, I want to show you the most intense form in which heat can be produced on this earth. There is no hotter object that we can obtain than that of the electric arc. I will try and produce this arc. You observe that when I bring these two pieces of carbon together, a current of electricity passes between them, and the passage of the current of electricity between them creates such an intense temperature that a brilliant white light, as you see, is produced. Incandescent particles of carbon pass between the two points, forming a sort of bridge or arch, which is called the electric arc. But the temperature of this arc is, as I said before, the highest temperature that we can produce; it has been measured, and is found to be 8,500° Fahr. That is a temperature that can hardly be conceived; the melting point of iron is only about 1,200° Fahr.; the melting point of platinum, which is one of the most refractory metals we have, is about 3,000° Fahr.; but here in the arc we have the intense temperature that nothing can withstand, equal to 8,500° Fahr. The color is really due to the combustion that takes place between the materials forming the arc. I have just used two pieces of carbon, but I will now try other materials—copper, iron, and zinc. You will see a difference in the color of the light, due to the fact that metal is burned in the arc instead of carbon. Every metal has its own distinct and particular color, and the presence of the different metals can be detected by the character of the small arcs produced.
I have shown you that we have two modes of producing intense heat, and therefore light, by electricity. I want now to show you how we produce electricity. The first essential for the production of electricity with a hand machine like this is a good dinner. The energy provided by beef or mutton enables the operator to turn the big wheel of the machine, whence motion is transmitted to the apparatus for producing the electricity. This machine when rotated causes a coil of copper wire to be whirled in a magnetic field, and that rotation of the coil in a magnetic field converts the energy derived from the grass and from the mutton through the machine into electric currents; those electric currents flow through wires that are under the table, they will appear in the two wires I hold in my hand, and will, I hope, reappear in the little glow-lamps I have before me in the shape of heat, and then of light when I attach the wires. The light of the glow-lamp is of just the same form of energy as that which passed from the sun to the earth, and by beginning backward from the lamps we have light, heat, electric currents, mechanical motion, food or fuel in the shape of mutton, grass on the South Downs, to the sun. Whichever way it is taken, you will find there is direct action between the sun and the glow-lamp. The lamps are now burning, and you see that we are able to produce electricity to our hearts' content. Down-stairs there is a gas-engine; the gas-engine is at work; the gas-engine works because the gas supplies energy which, stored up in the bowels of the earth in the form of coal for ages and ages, has been extracted; it has been converted into gas at the large gas works down the River Thames, it has been brought up here, it is burned in the gas-engine, and produces energy in the gas-engine exactly in the same way as the mutton or
beef produced energy just now. There is a dynamo down-stairs exactly like the dynamo that we have upon the platform, and the current that is produced is exactly as the current we just obtained, and is sending electricity through all the lamps in this room. The currents of electricity passing through the lamps are producing intense heat, the heat is producing the incandescence of a fine carbon filament, such as I will show you directly, and the consequence is that we are now being lighted in this room by the energy that unmistakably and undisputably arrived on this earth millions of years ago in the form of sunshine.
We can store up the energy in batteries. I shall show you to-night two or three different forms of battery. Here is what is called a primary battery. The only difference between a primary battery and a secondary battery is this, that a primary battery consists of chemical elements that at once combine and produce electricity by combustion, whereas a secondary battery involves some anterior electrical action, which prepares the surfaces of two bodies to put them in exactly the same condition as a primary battery. Here is a primary battery known as the Schanschieff, which is charged with a solution of sulphate of mercury, and into that sulphate of mercury we will dip plates of zinc and plates of carbon. Zinc has a greater affinity for the sulphuric acid of the sulphate of mercury than mercury has; the sulphuric acid will at once combine with the zinc; it will burn the zinc just as the gas burned just now, but instead of burning with heat and light in the battery, it burns in the form of electricity, which appears in the glow-lamps attached. You see that the moment the zinc and carbons are placed in the cell electricity is produced, and the lamp is lighted. The form of battery from which we are drawing our electricity to-night is the accumulator, or the storage or secondary battery. The secondary battery simply consists of plates or "grids," as they are called, one filled with litharge, and the other with red lead; the one becomes pure lead, the other becomes peroxide of lead; the plates are combined in this form, and then placed in a glass cell, and upstairs there are 52 of these E.P.S. cells, which have been charged all day long by the gas-engine of which I spoke, and which now contain a store of electricity that I shall make considerable use of to-night before I finish.
I showed you the form of electric light which we call the arc, and I have here to-night two or three different forms of arc lamps, which I will show in action. But I want you to see this arc light for yourselves, and I want you to feel, as I feel, that in all nature there is nothing more wonderful and nothing more beautiful than the action of electric currents in the arc. The light is, as I attempted to show you, the very same light that came from the sun. I can show you that it is of the same character as the light of the sun, and in the lantern on the table there is an arc lamp the light of which we will throw on the paper before me in the form of a spectrum. There you see the spectrum in all its purity; the spectrum from the sun is no purer as regards light than what you now see. There you see all the colors of the rainbow, and I had intended, if it were possible, to show you in the first experiment, in which we raised platinum wire to incandescence, that the first color would be the red, then the orange, then the yellow, then the green, then the blue, then the indigo, and lastly the violet. Beyond the violet there are rays of light which we cannot see; they are the rays that produce the photographic pictures, and, had time permitted it, we would probably have taken to-night a picture by means of the arc lamps, but it requires a long time to do so, and it really is no more interesting than an ordinary photographic picture. There are all the different colors of the rainbow. Those who are anxious to remember the order of the colors can very easily do so if they will remember this simple sentence, "Read over your good book in verse." The first letter of each word in that sentence gives the first letter of the color in the order of the spectrum. It would be a very good thing if some of our artists were to study and remember the colors of the rainbow, for it is an extremely rare thing indeed to find a picture with the colors of the rainbow properly depicted, sometimes they are upside down, sometimes they are mixed, and if you discuss the fact with an artist, he will say, "I do not care about your science. I simply paint my own impressions."
I will now show you the arc in another form. We are to-night connected in this room—I have told you there is a gas-engine down-stairs; there are also secondary batteries upstairs—but we are in connection with the Grosvenor Gallery in Bond Street. The Grosvenor Gallery has a central station where a very large dynamo is at work, from which electricity is supplied to different parts of London; many thousand lamps are fed, in a great many clubs, theaters, and private houses; they are all lit up by the currents generated underneath the Grosvenor Gallery. The Grosvenor Gallery Company, through their engineer, Mr. Ferranti, have very kindly undertaken to supply us to-night with a current. The current is supposed to be a very dangerous one, in reality it is not; there is no electric current that has ever been produced that is one-tenth as dangerous as a steam boiler, and all these currents, however immense they may be, are very simply controlled, and very easily brought within the region of safety. There is no doubt that with the apparatus that is now being handled in this room, if anybody were deliberately to put one wire in his mouth and the other in his hand, he would have the funeral service performed over him in two or three days; but those who know what they are about no more handle electric light wires carelessly than they put their hands in a furnace or their noses in boiling water. We acquire experience by practice, and we know by this time pretty well how to deal with electric currents. Now, you see in the lower arrangement there that safety catches are being put in, which render any accident quite impossible. Passing through each of those boxes there is what is called a "cut-out" safety fuse, or safety valve, and should, from any accident, anything go wrong in this theater, or in any way with the system outside the theater, the safety fuses would burst, and would so remove all danger from inside. The switch has now been turned, and by it the current from the Grosvenor Gallery has been brought within our reach. You see an arc light produced by it, and you see how intensely bright and brilliant that light is. I do not want you so much to see that light itself, but I want you to see its projection, or picture; and if Mr. Wickham will kindly direct it on that white paper, at the
end of the room furthest from the table, you will see a picture of the carbons which are now emitting that intense and brilliant light. You will see that between what appears to you as the top carbon (but which is in reality the bottom carbon of the two) and the bottom one there is playing, apparently, a shower of minute fragments of something, but which are in reality innumerable minute flashes of lightning, there is a constant uninterrupted shower of electric shocks passing, that produce that intense brilliancy, and that very bright appearance. There is intense commotion, a terrible surging about of matter in a molten condition. Well, that arc that you see is produced by the currents from the Grosvenor Gallery. They are alternating currents of electricity, currents that are constantly and suddenly circulating backward and forward. The arc that we have at this other end of the room is a direct current one, and it is now projected on to another sheet of paper, where you see a different form of are altogether. This arc is produced by the direct current from a battery. You will see the form is quite different from that in the alternate current arc. You heard a peculiar hissing sound just now; that is a peculiar phenomenon in arc lamps that has attracted a good deal of attention from physicists, but nobody has yet arrived at a satisfactory conclusion as to the cause. The lamp sometimes sings and sometimes hisses, and while thus behaving it produces an intense and variable inverse electro-motive force, that has to be overcome before the current can produce a steady and silent arc. You will notice in the upper carbon of this form of lamp a kind of cup, or "crater." The lower carbon forms a kind of point, a raised surface, and between the two there is on the projection that which appears as a glow, but which in reality has very intense heat, reaching, as I told you, a temperature of 8,500° Fahr. In those two projections you have, I think, within my experience for the first time, been shown in public an alternate current arc and a direct current arc at the same time, so that you are really able to see what I do not think most people have seen before.
There are a great many different arc lamps. I have not time to bring before you all the various lamps that I might have secured for your inspection. There is the Brush lamp, that for a long time lit up the streets of our city, and I sincerely hope very soon is going to light up the city again. There was the Jablochkoff lamp, that lighted up our Thames Embankment, and which can be seen, on going down the Strand, at the Tivoli Restaurant, not far from here. The offices of the Daily Telegraph, in Fleet Street, and many other places, are lighted up by different lamps, many of them excellent. Our experience of the last two or three years at the exhibitions has taught us that there are a great many different kinds of arc lamps, but all these arc lamps are lamps so constructed that they cause the pair of carbons to be fed, to be kept together, as they consume, at the same rate as they do consume. The mechanism is of great delicacy, it acts with great promptitude, and the one that we have here to-night is one of the last and one of the best; it is known as the Brockie-Pell lamp. The lamp now at work is a Brockie-Pell, and for those who are interested, a diagram representing it is upon the wall, and its operation I shall be very happy to explain after the lecture; it feeds with great rapidity, with great convenience, and is one of the steadiest lamps we have.
There are objections to the arc light; it is extremely dazzling and irritating to the eye. Although the arc lamps we have here to-night are of the very best of their kind, and are certainly almost steady, still they have little irregularities in their action, and worst of all, they throw intense shadows. The light from them is not very well diffused, still the light is very brilliant, and it raises the envy of a good many people. For instance, the Brush Company were once establishing a light in the neighborhood of Cork, and an Irish farmer was remarkably struck by the appearance and the steadiness of the light, so he came to the engineer in charge and asked him, as a great favor, if he could kindly tell him where he got his oil from.
I must now go from this to the next branch, the glow-lamp, the lamp that is burning so steadily and so nicely above us. For this lamp we do not use platinum, such as I heated before you just now, but we use carbon, so fine that although I have probably one hundred or more in my hand, they feel no heavier than a feather. These extremely fine filaments of carbon are made with very great care from cotton. I cannot show you the whole operation of making carbons and some of the preliminary operations connected with the making of the lamp; but owing to the kindness of the Anglo-American Brush Company, their manager, Mr. Sillar, is here to-night, and we shall have the pleasure of seeing how the whole operation of the manufacture of one of these glow lamps, such as we have above us now, is carried out. The carbons have already been formed, but the first process is that the cotton fiber is carefully tied and wrapped around pieces of carbon, as you see. It is then placed in a furnace and carbonized. After being thus prepared, a glass tube of special quality selected for the purpose is used to form the glass globe. Mr. Donaldson will take a piece of the glass tube before you, and will blow it into the shape similar to the lamp I hold, which is of the very familiar pear-like form. The carbon filament will then be fixed in the glass bulb, the latter will be exhausted and sealed, and the whole process be passed through before your eyes. I must first of all show you why it is necessary to take all this care. We have in front of the board one of these carbon filaments suspended, and we will now pass a current through it, and the carbon filament is raised to incandescence, it combines with the oxygen of the air, it is at once consumed, and, as you saw, we only had a light for a few seconds. Now, in order to make that light permanent, it is necessary to inclose the carbon filament in a glass globe, and to exhaust from that glass globe all the air, or as much of it as possible, and then, instead of having a life of a few seconds, the life of a lamp frequently continues for 4,000 or 5,000 hours. The first process, as I said, in making an incandescent lamp, after the carbon filament has been prepared, is that of blowing a glass bulb. The blowpipe has now been put on, and the intense heat of the Bunsen burner raises the glass to incandescence, to a soft, plastic condition, so plastic that the manipulator can do with it just
whatever he likes. Having got the glass to this particular shape, the filament will be placed inside it, first of all mounting the filament, which is an operation requiring a great deal of care and great skill in handling. It is an extremely pretty operation, and I beg to call your attention to it. The carbon is fixed inside a fine spiral of platinum, which is at the same time subjected to an intense current which decomposes the oil or the hydrocarbon in which it is placed, the carbon deposits on the carbon filament, and cements it to the platinum spiral. That is called mounting the filament. When that is done, the filament is fixed in the glass globe, and the platinum and glass are fused together. The brilliance of the platinum can be seen during this operation, and it is very pretty. I do not know how it would have been possible for us to have glow-lamps if it had not been for the fact that the coefficients or rates of expansion of platinum and glass are practically exactly the same, and the result is that when the platinum and glass are combined together, as they are in a glow-lamp, the two contract and expand at the same rate, and the result is there is no leakage; if there had been leakage through the glass, it would have been quite impossible to have made a glow-lamp. The success of a glow-lamp depends upon the vacuum produced, and the next process is to cement the lamp so far to a vacuum tube connected to a mercurial air-pump. The one before you is Mr. Lane Fox's. It would have been also impossible to have produced these beautiful glow-lamps without the mercurial air-pump, so that the success of electric lighting and its perfection depend upon, first, the similarity of expansion of glass and platinum, and secondly upon our power of producing a vacuum. As it takes ten minutes or a quarter of an hour to carry out the process of exhaustion, I will proceed with other portions of my subject, and presently, when the time is ready, Mr. Sillar will inform me, and we will light up the lamp that has been made before you this evening, and, I hope, with success. The operation we have just seen is one that has been just as interesting to me as it has been to you. There are very few who are permitted to see this operation. We once had it before in this hall when General Webber read a paper on glow-lamps, but with that exception I am not aware that the manufacture of glow-lamps has ever been shown in public before. It is most wonderful to watch the marvelous way in which glass can be twisted and turned to our ways and to our wants, and the skill with which the blower is able to manipulate glass in its plastic condition, and to shape it in any form he likes, is an operation which never ceases to excite one's wonderment. The form of lamp that is being made before us is of the ordinary size that we see used generally, but there are a great many different sizes of glow-lamps. For instance, here is a very small lamp; above me you will see, if I may call the small one a dwarf, there is a giant glow-lamp. It is a lamp invented by the Honorable Charles Parsons, it is made by the Sunbeam Lamp Company, of Gateshead, and is called the Sunbeam lamp; it has the same proportion to an ordinary lamp that an ostrich egg has to a hen's egg, and the light from it is of equally large proportion, as you see now the current has been turned on to it. It gives a light of four hundred candles, but it is rather too brilliant I see by your faces, and we will go back to our old friends of the ordinary size. There are also above us lamps of various sizes; there is a five-candle, ten-candle, sixteen-candle, twenty-candle, and a hundred-candle lamp. Here also are a fifty-candle Swan lamp, a sixteen-candle Swan, and an eight-candle Swan lamp. There are the ordinary sixteen-candle lamp; these are being burned from the Grosvenor Gallery. Here is a miner's lamp, which is supplied with a current by the Schanschieff battery, the same as I showed you at first. The peculiarity of this arrangement is that when the battery is turned upside down the light goes off, the zincs and carbons occupy one half of the cell, and the solution the other half, the zincs and carbons being at the bottom, and the battery is not excited unless contact is made with the carbons and zinc. Such a battery as this will maintain its lamp for 12 or 13 hours. There are several forms of the Schanschieff battery. Here is a portable form, and lamp connected with it by a flexible wire, which can be used when traveling; or in the night, when you want to know the time, you can have a lamp and battery like this by your bedside, and you can turn it upside down, and produce a light, see the hour, and turn the battery back.
These glow-lamps are used for different purposes and ways. They may be used with care, they may be used recklessly; their duration depends a good deal upon the care with which they are used. A practiced eye, one who is accustomed to deal with electric lamps, can tell at a glance when the lamp is raised to a proper incandescence; but there is a point in all lamps that is a sign of danger, and indicates "breakers (or breakage) ahead." Whenever in an electric light installation a glow-lamp begins to show a blue effect, then breakers are ahead; the current must be reduced or other steps taken. I want to show you this blue effect, which is extremely pretty, and I want you to see the gradual stages through which a lamp passes from long life to death, or rather to a very short and merry life. We can make the life of a lamp just exactly what we like; we can make a lamp last a minute, or we can make it last a hundred years, and the number of years of its duration is simply dependent upon the current employed. I have here a glow-lamp, and I pass a current through it. There is no blue effect at present; the current is increased, and the carbon filament is raised to a high state of incandescence. In such a state it would not last for a long time, not more than ten minutes or a quarter of an hour; but it does not show the blue effect yet. On further increasing the current the blue effect appears, though I doubt whether it is visible to many of the audience; a little more current is put on, and the blue effect is very marked, the globe itself looks very brilliant, and—there—the current has been increased until the filament has parted.
It is always better, when making an observation or experiment, to know what you are going to see, so that you can direct your attention to exactly what is being done or to what you want to know. If I put another lamp through the same experiment, you will be better able to understand this blue effect, and see just that point where the lamp is about to give out. The current is now on, and is being gradually increased; the lamp is now intensely blue, and—there—it has gone in the same way exactly as the other one did. The way
in which lamps burst is sometimes very beautiful; they disintegrate, they seem to volatilize, and the substance of the lamp is projected with great force against the side of the globe. On the table there are several beautiful specimens showing this effect.
The glow-lamp in process of manufacture before you is now being unsealed from the pump; it is now exhausted, and we will pass a current through it so as to raise it to incandescence. The current is now on, and you see the lamp burns with full brilliancy. The next experiment is rather a cruel one, because it is willful destruction. I will not destroy the lamp that has just been made before us, for I will keep it as a memento of this evening. I want to show the safety of the electric lamp. Many people imagine that there is a great deal of danger about it. I will take a handkerchief, and in it place a lighted lamp, when, on the globe being broken, the carbon filament instantly goes out, and there is no damage to the handkerchief, or the slightest appearance of scorching or heating upon it. On breaking that lamp you heard a report. That is due to the vacuum, which, on sudden rupture, the air rushes in to fill. These lamps will not only burn in air, but will actually burn in water. Here I have a lamp which on placing in a bowl of water continues alight in the water just as well as in the air. You can imagine what an immense boon that is to our divers and others who unfortunately have to work under water for our benefit.
I will not attempt to occupy your time in speaking of the beauties of this wonderful light, how it removes really poison from our air, how it is very good for sore eyes, because it burns with such steadiness that those who work under it really never find, in any shape or form, any inconvenience or discomfort to the eyes. It is extremely cleanly; it does not fill the air we breathe with noxious fumes. People are little aware of it, but it is a very simple calculation to show that thirty gas burners produce a gallon of water in an hour, so that if you have thirty burners in a shop, for instance, alight for six hours, six gallons of water are produced and the water can very often be seen running down the cold windows of shops. That water absorbs sulphur and sulphuric acid, and when deposited on books and decorations destroys them. If we could only get the electric light cheap, delivered at our doors, then everybody who has an idea of luxury and comfort would at once take it.
I want now to show you some of the dodges of the electric light. First I will show you that by the action of a cut-out an excess of current is prevented from injuring the lamps. A cut-out is inserted so as to protect a group of lamps here, and on a large current being sent you hear a crack, and the lamps have gone out; the safety fuse has perished in performing its duty. To prove this we will renew the cut-out, and on the proper current being turned on, you see the lamps are sound. Here is an electric cigar lighter. I raise this up and the wire in front of it comes to a state of incandescence, and I have there, as you see, sufficient heat to light my cigarette. Some years ago, I had my daughter's doll house, which was furnished by herself, fitted up with the electric light, and I thought that some of my younger hearers to-night, who were still in the doll age, would appreciate the way in which a doll's house can be lighted up by electricity. You now see the doll's house illuminated; it has a hall door lamp which lights up on the opening of the door; the house has rooms furnished, occupied with handsome dolls, and fitted with every kind of contrivance; the doll who occupies the drawing room has the convenience of a portable lamp, which she can move about wherever she likes, and each room and the kitchen has a particular form of lamp.
I have also here a model of that famous ship the Captain, which was wrecked off Cape Finisterre. The model has been fitted with electric light, and you now see the mast head-light, the red light for the port side, and the green light for the starboard side; there are high jinks going on in the saloon by the aid of the electric light, and there is also a search light which can be used for looking for the advance of the enemy. A beautiful phosphorescent effect is produced upon the water, which is covered with blue cotton wool, in which a lamp is placed, causing really a very pretty illustration of what the phosphorescence of the sea is like.
Here I have an apparatus for heating curling tongs by electricity; here is a flat iron treated in the same way, and here is a kettle in which the current is carried to boil water. I travel a good deal, and I always carry in my traveling bag a battery like this, which is one of Pitkin's secondary batteries; it is light and extremely convenient. I can strap it on my shoulder like an opera glass. To this is attached a reading lamp which I fix in my waistcoat, and to the astonishment of my fellow travelers, when the shades of evening are beginning to set, I take out the lamp and put it in operation—so. My reading lamp is thus provided, and it is fixed in the most convenient position, for the light falls just where it is wanted, it does not offend the eye, and enables me to read the smallest print. I have always got with me my own light, perhaps much to the annoyance of my fellow passengers, and with the electric light machinery at my own house, I have little or no trouble in recharging the battery, or keeping it in order. The Pitkin battery is also applied to a miner's lamp.
EFFECT OF CHLORINE ON THE ELECTRO-MOTIVE FORCE OF A VOLTAIC COUPLE.[6]
By D. G. Gore, F.R.S.
If the electro-motive force of a small voltaic couple of unamalgamated magnesium and platinum and distilled water is balanced through the coil of a moderately sensitive galvanometer of about 100 ohms resistance, by means of that of a small Daniells cell, plus that of a sufficient number of couples of iron and German silver of a suitable thermo-electric pile (see Proc. Birm. Phil. Soc., vol. iv., p. 130), the degree of potential being noted, and sufficiently minute quantities of very dilute chlorine water are then added in succession to the distilled water, the degree of electro-motive force of the couple is not affected until a certain definite proportion of chlorine has been added; the potential then suddenly commences to increase, and continues to do so with each further addition within a certain limit. Instead
of making the experiment by adding chlorine water, it may be made by gradually diluting a very weak aqueous solution of chlorine.
[6] Read before the Royal Society, May 3, 1888.
The minimum proportion of chlorine necessary to cause this sudden change of electro-motive force is extremely small; in my experiments it has been one part in 17,000 million parts of water;[7] or less than 1⁄7000 part of that required to yield a barely perceptible opacity in ten times the bulk of a solution of sal-ammoniac by means of nitrate of silver. The quantity of liquid required for acting upon the couple is small, and it would be easy to detect the effect of the above proportion or of less than one ten-thousand millionth part of a grain of chlorine in one tenth of a cubic centimeter of distilled water by this process. The same kind of action occurs with other electrolytes, but requires larger proportions of dissolved substance.
[7] As one part of chlorine in 17,612 million parts of water had no visible effect, and one in 17,000 million had a distinct effect, the influence of the difference, or of one part in 500,000 millions, has been detected.
As the degree of sensitiveness of the method appears extreme, I add the following remarks: The original solution of washed chlorine in distilled water was prepared in a dark place by the usual method from hydrochloric acid and manganic oxide, and was kept in an opaque, well-stoppered bottle in the dark. The strength of this liquid was found by means of volumetric analysis with a standard solution of argentic nitrate in the usual manner. The accuracy of the silver solution being proved by means of a known weight of pure chloride of sodium. The chlorine liquid contained 2.3 milligrammes or 0.03565 grain of chlorine per cubic centimeter, and was just about three-fourths saturated.
One tenth of a cubic centimeter of this solution ("No. 1") or 0.003565 grain of chlorine was added to 9.9 c. c. of distilled water and mixed. One cubic centimeter of this second liquid ("No. 2"), or 0.0003565 grain of chlorine, was added to 99 c. c. of water and mixed; the resulting liquid ("No. 3") contained 0.000003565 grain of chlorine per cubic centim. To make the solutions ("No. 4") for exciting voltaic couple, successive portions of 1⁄10 or 1⁄20 c. c. of "No. 3" liquid were added to 900 cubic centimeters of distilled water and mixed.
I have employed the foregoing method for examining the states and degrees of combination of dissolved substances in electrolytes, and am also investigating its various relations.
THE WIMSHURST INFLUENCE MACHINE.
In our last number we gave illustrations of this machine, in which 12 plates 30 in. in diameter are used, and sparks nearly 14 in. in length are obtained. The engraving, from photographs, shows sparks 13½ in. in length, obtained from this machine.
DISCHARGE FROM THE WIMSHURST INFLUENCE MACHINE.
SANITATION IN MASSACHUSETTS.
This subject was prominently considered by Dr. H. P. Walcott, of Boston, in his address on state medicine, at the meeting of the American Medical Association recently. The vital statistics of Massachusetts, he said, showed a declining death rate for the last thirty-six years, under the influence of state sanitation. The most marked decrease had been observed in the mortality from zymotic diseases; there had been a less decided reduction of that from constitutional diseases; that from local diseases had increased; and that from mental diseases and from violence had remained stationary. In 1876 there was not a single death from small-pox. Typhoid fever had diminished most in cities having a good system of sewerage and water supply, and least in towns without such improvements. Diphtheria, which reached its maximum in 1877, had since declined, until it now caused only one per cent. of the total mortality. Ovariotomy saved more lives than any other surgical operation, but, taking Somerville as a basis of calculation, the ascertained results of preventive medicine had saved more lives in ten years, among thirty thousand people, than ovariotomy would save in the same time among two millions. Great attention was given to small-pox, which had killed but 5,500 persons in Massachusetts in thirty-six years, and to cholera, which had destroyed only 2,000; but too little heed was given to scarlet fever, with its mortality of 37,000, and to typhoid fever, with its mortality of 45,000.—N. Y. Med. Jour.
THE CARE OF THE EYES.[8]
By Prof. David Webster, M.D.