674 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



complicated, and could hardly have rested twenty years, if it be really 

 practicable. 



In all these methods of employing stationary eng-ines, the cars were car-' 

 ried through the air and were exposed to all accidents from weather, stray 

 cattle, etc. A totally ditferent plan has been invented by Rammcl, of Eng- 

 land. Instead of a small piston, I'equiring intense pressure, he employs a 

 large piston, requiring only such pressure as a stiff breeze exercises on a 

 sail. To do this he builds his railroad within a tube, and makes the front 

 of the carriage a large piston fitting the tube loosely, a brush of hog's 

 bristles being the only packing used. He then obtains his current of air 

 by means of an atmospheric ejector or huge centrifugal wheel, the air 

 being taken in at the center and ejected at the periphery to exhaust air 

 from the tube, and the air being taken in at the periphery and sent out at 

 the center to produce compression in the tube. 



The experimental pneumatic railroad at the Crystal Palace has demon- 

 strated tliat this mode of locomotion is very agreeable, being a gentle 

 gliding motion without jar, smoke, dust, or noise; that it is capable of 

 very high velocity, say one hundred miles an hour; that it is perfectly 

 safe, there being no danger of explosion, of running oflf the track, of 

 encountering stray animals or fallen trees, etc.; that it is practical and. 

 pleasant in all states of weather; that the ventilation is perfect, as fresh 

 air is constantly supplied to tlie car by the propelling current, and that in 

 case a car should break down there would be merely a stopping of forward 

 motion without danger to life or limb. 



Is Rammel's pneumatic railroad then perfect? Does it meet all require- 

 ments of economy, speed, safety, etc.? By no means. It requires an 

 American inventor to perfect the "pneumatic way." 



Rammel, to move a carriage from one end to the otlier of the tube, must 

 put twiqe the full of the tube of air in motion, and must therefore over- 

 come a double amount of inertia and friction. His stationary engine must 

 remain idle until a car is ready to start. He must have a telegraph from 

 station to station, to notify when the engine is to be set to work. He can 

 have only one car in motion in the tube at one time, and must bring the 

 whole column of air to rest to stop the car, thus losing a large amount of 

 accumulated force. To return a car he must stop and reverse his air wheel, 

 thus losing another large amount of accumulated force. 



Now, by attending to a description of the annexed diagram, we will 

 see in what a simple and masterly manner Needham overcomes all tj^ese 

 objections and perfects the pneumatic way. A, fig. 1, is a rotary air pump 

 which is connected with a continuous circuit cf tube. B, B, C, I) and D 

 are stations, each having two gates for isolating a section of the tube. 

 These gates are shown both open at B, B, both closed at C, and one open 

 and the other closed at D, D. When both gates are open as at B, B, the 

 current of air, produced by the pump A and indicated by the arrows, passes 

 straight along through tlie station, and a car going with it would not be 

 stopped. When both are closed, as at C, the current passes the station 

 through the bent tube shown beside it; the car, however, can not pass 

 round the bent tube, but must stop in front of the gate. When one gate 



