Perhaps the very large increase in steam shipping, and the change from sailing ships and paddle steamers to screw steamers, has been one of the greatest improvements of recent times, and it is none the less real or important from having been gradual, while the result to this neighborhood has been most beneficial. This change has been due in great measure to the introduction of very economical marine engines, chiefly of the compound type, together with better boilers carrying a higher pressure.
The speed and regularity of ocean steamers has also greatly improved, and one small scientific improvement has added much to the safety of traversing such seas as the Atlantic at a high speed--namely, the careful and continual use of a good thermometer, to ascertain constantly the temperature of the sea-water at the surface. For if an iceberg is floating within a quarter of a mile--or even half a mile, if the sea is pretty smooth--the surface water will be several degrees colder than the rest of the sea; since the very cold fresh water, resulting from the melting iceberg, floats on the top of the sea water for some distance.
No doubt the use of iron, and now of steel, has contributed most largely to the increase of shipbuilding in this country. Good arrangements of water ballast have also proved very useful; and steam cranes and arrangements for loading and discharging cargo have greatly promoted the use of steam colliers, enabling them to make more voyages in the year.
Closely connected with marine engineering is the great improvement in the economy of stationary engines, which has become more fully developed during recent years, both in reference to waterworks engines and factory engines. In aid of stationary engines, "surface evaporator condensers" have been found very useful, particularly where the supply of water is very limited; and at waterworks it is now very common to pass the whole water pumped through a surface condenser, thus giving a good vacuum without the expenditure of any water, and with the result of only raising the temperature of the water a very few degrees, on account of its large volume.
Locomotives have shared to some extent in the general improvement in machinery. The boilers are better made, and are safer at the higher pressures now carried than they were formerly with a low pressure. Several new valve gears of great promise have been brought forward, both for locomotives and marine engines. Among them Joy's motion should be again noticed. Mr. Webb says: "The engine shown at Barrow has been at continuous work ever since the Barrow meeting, and has run 30,278 miles; we had it in for examination on the 18th inst., and found the motion practically as good as the day it went out of the shop, more especially the slides, about which so many of the people who spoke at the meeting seemed to have doubts. I do not think you could get a visiting card between the slides and the blocks; in fact, the engine has been sent out to work again, having had nothing whatever done to it. The first thing, of course, that will require doing will be the tires; as far as I can see nothing else will want doing for some time."
A very fine engineering work has now been accomplished in America in reference to navigation, namely, the deepening of the channel at the mouth of the Mississippi through the training of the river by jetties and banks. In consequence, ships of large size may now go up the river--there being plenty of deep water above the mouth--and bring down grain cargoes, without the expense and inconvenience of transshipment, thus reducing the freight of corn to this country. This great improvement is the work of Captain Eads. A somewhat similar improvement was the blowing up of about 50,000 tons of rock from the bed of the river at the narrow pass of Hell Gate, near New York. It is to be hoped that these good examples may spur on our friends on the Continent to improve their harbors, so that large channel boats may cross with comfort to the passengers, thus avoiding the excessive expense that a tunnel would involve.
Great improvements have been made in the illumination of lighthouses by oil lamps; a light equal to 1,300 candles has been produced by Mr. Douglass, of the Trinity House, and now two such lights will be placed one above the other, where required. The electric light has made such numerous and rapid strides that it is impossible even to notice its various applications; but on the one hand the lighting by Dr. Siemens of four miles of dock frontage at the Albert Dock of the London and St. Katherine Dock Company, together with the railway behind the warehouses, and the warehouses and ships themselves, and, on the other hand, the elegant and steady domestic light of Mr. Swan, are excellent examples of the two extremes in this department. I believe we shall have the pleasure of closely observing the Swan light during our visit here. The lighthouse electric light is also a noble application of the great power of a single electric light on the arc principle. The most powerful electric light in the world is situated near here on the coast, between the Tyne and the Wear. It is possible, and even probable, that one of the great uses to which electric force will be applied eventually, will be simple conveyance of power by means of large wires; and as a higher percentage of power is gradually being realized, this method will become more economical. I may mention that 60 per cent. has already been obtained.
The invention of Messrs. Thomas & Gilchrist, by which a very large field of ironstone is now, for the first time, made available for the purpose of making good steel by the Bessemer process, bids fair to make very considerable alterations in the steel-making trade, and in the hands of Mr. E. Windsor Richards it has been made a great success, while in Germany there are several works also using the process largely. Mild steel is now being used to a great extent for the construction of steam boilers as well as of ships, and in steel castings for a variety of purposes, such as spur wheels, frames of portable engines, manhole door frames, etc., etc. Among the uses to which steel may be put is the manufacture of steel sleepers in place of wood. It is a very encouraging fact that there are now, or rather there were already, at Dusseldorf, in 1880, 70,000 tons of iron or steel railway sleepers in use in Germany. Mr. Webb, of Crewe, has exhibited a very promising arrangement of sleepers and fastenings, to be made either of iron or steel. Steel sleepers should also be used for tramways.
If, now, some clever ironmaster could only accomplish the task of making a good "street pavement" of cast iron, the increased demand for pig metal would be enormous. It has nearly been accomplished already, by several different modes of construction; and there are very many streets where the luxury of wood pavement, which wears very rapidly, cannot be afforded, and where macadamizing will not stand the wear and tear of the heavy traffic. The use of ingot steel, or very mild steel, for making tin-plates is now an established thing, and manufacturers are now taking this metal for making large tinned sheets up to seven by three feet.
The making of casks by machinery, cheaper and better than those made by hand, is now an accomplished fact by Mr. Ransome's machines. There are twelve factories already established abroad, some turning out 2,000 or 3,000 casks a week. This is a good case of English invention taking the lead in a manufacture.