Proceedings of the Polytechnic Association. 917 



Adjustable brackets clamped to the columns, for the support of all 

 awning frames, will permit each store occupant on tlie route to attach 

 his awning high or low, inside or "outside of the columns, at pleasure. 

 The street-lamps can be attached to the columns, affording a surer 

 protection to the gas-pipes and lamps, and enabling a removal of the 

 present posts. And whenever the city or individuals may choose to 

 increase the number of lamps the supporting columns are all provided. 

 Station lamps placed over the balconies will amply light the ingress 

 and egress of each ear, and being accompanied by a movable colored 

 disc, with wires leading to the master's place within, will 

 enable him at all times to signal each car-driver on his approach, so 

 that no delay shall occur in stopping at a station in which there are 

 no persons waiting. Uniformity of velocity, a point most to be sought ' 

 for in these ways, is thus greatly enhanced. The minor details of the 

 pneumatic dispatch, yiz. : Stopping, starting, working automatic 

 signals, operating side branches, employing auxiliary stationary 

 engines on long reaches, &c., will be determined by the special 

 circumstances of each case. In starting, the power of the rotary 

 pump or fan is comnmnicated so gently through the elastic medium 

 (the air in the tube) that, though motion is produced almost 

 instantaneously in all parts of tiie circuit, there is no jar or violence 

 calculated to injure anything. In stopping, the discs of the piston 

 carriages infringe upon a cushion of air at the station Atith such perfect 

 elasticity that the carriage is brought to rest without the least jar. 

 !No collision can possibly occur, as all parts of the air column within 

 the tube moves in the same direction at the same time. There is no 

 possibility of running off the track, and, as in the case of the modern 

 velocipede, the more rapid the motion the more direct and easily 

 will the piston carriage, running on a single track at the bottom of 

 the tube, hold its upright position, without bearing laterally against 

 the inner surface. 



Upon the scoi-e of both capital and time, required to complete an 

 underground or elevated railway, unquestionably the comparison is 

 largely in favor of the latter plan. And the question after all is, 

 will it pay ? 



If, as is claimed, a double track elevated way wit-h pneumatic 

 dispatch can be built for less than five per cent of the money, and in 

 less than ten per cent of the time, required for an underground road, 

 certainly it is worthy the careful consideration of capitalists and 

 citizens. 



