The daily morning journal and courier., 1894-12-21


 course the more air one pumps into the reservoir the greater pressure to the square inch one gets. The compressed air works like steam. But steam can not be carried through pipes out of doors any great distance, for 1t would lose It's heat. would condense. and soon turn back to water
 Cleaning cushions by compressed air is one way of using 1t that few people know of. Visitors to the sani- tary canal are always interested in the rock drills which bore the holes for the dynamite cartridges. and almost everybody knows that the brakes of passenger trains are operated by com pressed air.
 q know of a machine shop where there Is not a belt. piece of shafting, or an electric wire for all the machin- cry. from little emery wheel to a twenty-ton crane, Is operated by com pressed air. The shop is traversed by large pipes from the air reservoir, and from these main pipes smaller pipes run down to the machine. whether drill, planer. shears, lathe, bending rolls, milling machine, punch, drop hammer. press, or cold saw, has It's own motor or engine, and the mere turning of a valve starts or stops the machine.
 "A pneumatic.clock system has lately been installed in the new criminal court building in Chicago. Pneumatic clocks are not new. for they have been used in Paris for twenty-five years. Now over 10000 clocks are operated and reg ulated from the central clock by com pressed air.
 | "The pneumatic-clock system install ed in Paris twenty-five years ago was the beginning of the compressed air central power system, which supplies over 10000 horse power to users in the French capital. It is used there for all | purposes, from running clocks to oper- | ating dynamos for electric lights. The | central station furnishes air at a pres | sure of seventy-fve pounds to the square inch. It is sent around the city under the streets in pipes, and is sold to customers by meter, just as gas is. "The solution of the smoke problem in Chicago Is easy. Put a central pow CT station where the smoke will bother no one, and from this station send elec- tricity, high pressure water, or com pressed air to the business centre and to the stock yards. The cheapest pow CT that can be used in this way is com pressed air. Elevators, printing press es, wood and iron machinery, and, in fact, anything operated by steam can be operated by compressed air. Some day we shall have pipes for compressed air under the pavements of Chicago streets, and there will be no smoke if the tugboats and locomotives can be subdued."
 Asphalt used for street paving is re- fined by compressed air. In its original shape, just as 1t comes from Trinidad, asphalt Is too soft for street paving and is not homogeneous. To refine 1t the asphalt is boiled in kettles for three or four days, and while the heat is on it must constantly be stirred. Pipes with numerous holes are placed at the bottom of the kettle, and while the as- phalt is boiling compressed air Is forced through the pipes, and, escaping through the holes 1t agitates the thick, black stuff. At first the air comes to, the surface in bigfsbubbles, and the asphalt slobbers all over the inside of the kettle, but at the end of three days the asphalt has become so thin that the air makes 1t boil in little bubbles. and it is then drawn f,ia barrels, where it cools hard and even. In France they make a sort of silk from wood pulp by the aid of compress ed air. The wood pulp is put through a chemical process which changes it to- a stick substance like gelatine. It is then placed in a closed tank and com pressed air is introduced. The air first presses the substance through filter and then into a smaller tank which is under the large one. This tank Is in g. horizontal position, and from it spring hundreds of glass pipes, in each of which the hole is about the size of silk fibre. The wood pulp is forced through these tiny holes and comes out in the shape of threads so fine that six of them are required to make a thread strong enough for weaving. {
 Compressed air was the paint brush which placed the color on the worlds fair buildings, and which to-day is painting railroad bridges and corru- gated iron plates for buildings. The compressed air not only draws the paint from the tubs to the place where 1t Is to be used, but, by atomizing the paint, sprays it over a large surface and drives in into the wood. In the big shipyards of Cramp & Sons, Philadelphia, where government armored cruisers are built all the calking of war ships is done by compressed air, and one compressed air calking machine does the work of four men. This calker can strike 1000 blows minute ..
 :, The same tool in a modified form Is used by stone cutters for dressing or carving granite. The little engine which does the work is in the handle of the tool, which is about as large as a -ohisel handle. The air is brought for the tool by a small rubber pipe, which is so flexible that 1t can be handled easy and at any angle. A piston and spring shove the tool in and out; and 1t can be 50 regulated that the most delicate work can be done with it.
 Many of the dump cars on the sani-