The wonders of modern mechanismA résumé of recent progress in mechanical, physical, and engineering science . nd varietv of its uses. This mav be the acje ofelectricity, yet compressed air is coming into use for pur-poses entirely similar ; in fact, it steals in where electricityleads the way. The power of compressed air was knownlong before we began to understand that the electric cur-rent could be made useful, yet air as a motive power forrailways, and in shops for driving tools individually, hasonly come to be used after we had tried electricity andfound that such installations were conveni
The wonders of modern mechanismA résumé of recent progress in mechanical, physical, and engineering science . nd varietv of its uses. This mav be the acje ofelectricity, yet compressed air is coming into use for pur-poses entirely similar ; in fact, it steals in where electricityleads the way. The power of compressed air was knownlong before we began to understand that the electric cur-rent could be made useful, yet air as a motive power forrailways, and in shops for driving tools individually, hasonly come to be used after we had tried electricity andfound that such installations were convenient and econom-ical. The machine that renders air serviceable as a motivepower is called an air-compressor. It looks much like asteam-engine, and usually there is a steam-engine cylinderincorporated in its meciianism at one end of its bed, while COMPRESSED-AIR MECHANISMS. 159 an air-cylinder occupies the other end. At every stroke acylinderful of air is compressed by a piston and drivenout through a large pipe, the action being the reverse ofthat by which steam drives the piston in its cylinder. Fig. THE RAND DIBECT-ACTING STEAM AIR-COJIPRESSOR. The best forms are of the horizontal duplex type of steam-eno;ine, with air-cvlinders behind and in line with thesteam-cylinders, and so coupled that one piston-rod servesfor both cylinders. Storage-tanks of compressed air for use in driving street-cars are quite as much in use as are storage-batteries for thesame purpose. Air is so used to-day in France on a linebetween Paris and Nogent-sur-Marue and on the NantesRailway. The Paris road is operated by about six largetanks per car, each set of tanks containing a supply of com-pressed air sufficient to carry the loaded car over five milesof graded road, or about eight or nine miles on a nearlylevel road. As a matter of fact, however, the cars are re-charged at stations about one and a half miles apart. Theyhave the advantage of being smokeless, also of makingvery little noise and
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Keywords: ., bookcentury1800, booksubjectmachinery, booksubjectmechanicalengi
