At the last annual meeting of the Royal Cornwall Polytechnic Society (Falmouth) there was, as usual, an interesting display of works of art and mechanical inventions, and prizes were offered which may, perhaps inspire further inventions. As examples we mention five hundred pounds for the best boring-machine applicable to Cornish mines: fifty pounds 'for the discovery of a new mineral in Cornwall or Devon likely to become commercially valuable;' and 'for a method, mechanical or chemical, of making marketable, with commercial advantage, ores or minerals produced in Cornwall or Devon, and hitherto regarded as worthless, or of little value.'
The so-called diamonds in the Diamond Rock Drill are in reality carbonite, a mineral found in Brazil. When first offered for sale, the price was fourpence a carat; now it is from fifteen to twenty shillings. These pieces of carbonite being firmly set in a 'crown,' form a drill which, when driven by steam, will pierce the very hardest of rocks. According to the nature of the rock, the progress will be from one inch to two and a half inches a minute, which in ten hours would amount to a considerable number of feet. The wear of the carbonite is so small that in boring quartz, which is not a soft rock, to a depth of thirty feet, not more than one sixty-fourth of an inch would be worn off. The dangerous reef in the estuary of the Tees is in course of removal by means of the diamond drill. Holes are bored; blasting charges are inserted; the rock is blown to pieces; two thousand tons a day are lifted by a dredger; and the total cost for all this is not more than four shillings a cubic yard.
Mr Handyside exhibited at the Cornish meeting above mentioned a locomotive which will ascend steep slopes of one foot in ten, or one in eight if required, and therefore may be turned to good use in a hill-country. The Brenner Railway, by which trains cross from Tyrol into Italy, has a rise of one foot in forty: on railway lines generally one foot in eighty may be taken as an available gradient: hence it will be understood that a locomotive able to run straight up hill without miles of zigzag will admit of much economy in railway construction. This new locomotive has, at its rear, a drum wound round with a chain, and is provided with self-acting grips, which descend at the proper moment, and biting the sides of the rails, after the manner of a vice, so fix the locomotive to the spot that it becomes a stationary engine. Some of the wagons are fitted with similar grips, to prevent the train from running back during the ascent. When preparing to mount a hill, the free end of the chain is made fast to the foremost wagon; the locomotive moves on the whole length of the chain and fixes itself; the drum begins to turn, and by winding up the chain, hauls the train up; and this process is repeated until the hill-top is reached.
Here then is a new appliance for the engineering profession. Its capabilities have been proved, as stated in the Report, at the new Avonmouth dock, where a Handyside locomotive has hauled the excavated material from the bottom of the basin, and deposited it wherever required for filling on the top.
Other advantages possessed by this locomotive are: that it can be used with rails much lighter, and consequently less costly than those in general use: that the drum and chain facilitate the passage of curves: that a train of coal-wagons may be close coupled as a passenger train; and that its break-power is complete, and being applied to the sides of the rails, does not injure the surface that bears the traffic.
We are informed that a steam tram car has been invented at St Louis, United States, which travels seven miles in fifteen minutes. The boiler, cylinder, coal-box, and water-barrel are ingeniously planned to occupy as little space as possible; and the inventor states that 'under ordinary circumstances the cost of fuel will not exceed three shillings a day.' For further particulars, inquirers must write to St Louis.
On looking at a map, one often feels a desire to tell off-hand the distance between two places. Among the instruments exhibited at Falmouth, Morris' Patent Chartometer, which may be carried in the pocket as easily as a watch, will enable any one to get the desired information. The 'works' of the chartometer are moved by a wheel projecting on one side. To measure any distance on a map, we are told it is only necessary to hold the instrument upright, and run the wheel along the line between two places, or the course of a river, or the sinuosities of a coast, and the indicating fly denotes the number of miles or parts of a mile. The distance is shewn at once, without the trouble of calculation, which is an important advantage. A Patent Measuring Instrument, by the same maker, is described as 'somewhat similar in character, being run along the surface to be measured. It measures up to one hundred feet; and is of the size of an ordinary watch.'
The practice of using leather belts for transmission of power in foundries and factories, which prevails largely in the United States, has been imitated in Lancashire and Yorkshire with satisfactory results. With belts there is less noise and less vibration than with iron shafting and bevelled wheels; the walls of the building are consequently not weakened by perpetual shaking, and diminution of roar and rattle cannot fail to be a benefit to all concerned. Nevertheless leather belts are costly articles, and if hemp could be substituted for leather there would be a saving of two-thirds of the cost. This has been proved in Dundee, where in one of the factories (Messrs A. & J. Nicholl's) rope-gearing is used for transmission of power to all parts of the building, and during an experience of five years, has given full satisfaction. The size of the ropes varies with the work required; the largest, in the instance here under notice, being six and a half inches circumference. The power is communicated directly from the fly-wheel, the rim of which, instead of cogs, is filled with circumferential V-shaped grooves. The 'life' of a rope is said to be from three to five years, though some ropes last much longer; which considering that they travel from three thousand to six thousand feet per minute, may be regarded as long enough.
The Proceedings of the Institution of Mechanical Engineers contains a description of Frisbie's Mechanical Fire-feeder—a contrivance which economises fuel, increases heat, and saves trouble when applied to the fireplace of a steam-engine or furnace. Underneath the fireplace is a mechanism which carries a movable hopper; the hopper is filled with coal, and by the turning of a winch, is raised until the fresh coal is pressed against the bottom of the fire. The smoke, having to rise through an existing fire, is nearly all consumed; and the pressure from below breaks up the clinkers, and causes them to fall away to the circumference of the fireplace, from any part of which, as the bars are made to rotate, they can be easily removed. Among the advantages of this method are: that 'the fire is not reduced in intensity by the cold fuel damping the flame,' as is the case in fireplaces of the usual construction: that 'each successive charge of fuel lifts up and most effectually pokes the fire:' that 'the cooling of the furnace by the admission of a large volume of cold air when the fire-doors are opened for stoking, is avoided;' and that 'a smokeless flame is readily attainable with a thick fire, although using smaller fuel than can be employed in ordinary furnaces.' Accepting this information, it is not out of place to mention that the furnace by which steam is generated for driving the machinery by which this Journal and our other works are printed, is fed upon a somewhat similar principle. Small coal (dross) is placed in a hopper at the near end of the furnace, and rests upon and is gradually carried into the interior and on to the far end (where it is dropped as clinkers) by closely connected parallel bars which traverse the furnace from end to end and slowly revolve round a 'drum.' The strength of the fire is regulated by a door, which may be raised or lowered by a winch, to admit of a greater or less supply of fuel, as necessity may indicate. The result is that combustion begins at the near end of the furnace, the smoke is consumed before it can reach the flue, a steady fire is maintained without admitting an unnecessary amount of cold air or necessitating the constant attendance of a fireman, and the economical desideratum of a perfect smoke-consuming apparatus is achieved. The apparatus goes by the name of Jukes' Patent, and has been in constant use for over twenty years. In comparison with ordinary furnaces, a saving of seven per cent. of fuel is effected. Why this patent apparatus for prevention of smoke is not in universal use, we cannot explain.
A curious fact was mentioned at a meeting of the Institution of Mechanical Engineers (Newhall Street, Birmingham). The boiler of a locomotive engine that had been working on a branch of the London and North-western Railway near London had become very foul through the constant use of hard water. Recourse was then had to a supply of water which had been softened, 'and at the end of a month the boiler was perfectly clean. The soft water had taken out the whole of the deposit, and not a handful of scale could be got when the boiler was washed out.'