ANNUAL ADDRESS. XXXIII. 



failed to fulfil what was promised for it (as in the Sturgeon 

 System Power Company of Birmingham), and this no doubt 

 checked the extension of experiments in its application for a long 

 time ; now, however, we find the exigencies of the present day 

 have brought forward two remarkable developments. The first 

 has been forced forward by the strong objection which exists in 

 New York and other American cities to the trolley system of 

 electrical street railways, where trolley wires will not be sanctioned 

 at all, and their much greater cost is an objection to conduit lines 

 for the same purpose. This has brought forth fruit in the domain 

 of compressed air for tramway propulsion, and we find as a con- 

 sequence, that compressed air auto-cars are at present running 

 side by side with the electrical tramway systems in New York, 

 on the Twenty-eighth and Twenty-ninth street lines of the Metro- 

 politan Railway Company. The motor cars of this company are 

 entirely self contained, the air being stored in cylinders under the 

 seats, at a pressure of 2,500 lbs. to the inch. The air is warmed 

 before use by means of coils in hot water cylinders. 



After a year's trial the system has been found so successful that 

 a large power house is now being installed with compressing engines 

 of 1,000 horse power, made by the E. P. Allis Company of Mil- 

 waukee. It has been found that with a "thirty foot car," the 

 consumption of air is from 30 to 40 lbs. per car mile ; and the cars 

 will run from 15 to 17 miles without recharging. This system of 

 tramway requires no capital to be sunk on the street, either under- 

 ground or overhead, except for the ordinary permanent way; there 

 is thus no interest on the first cost and maintenance of conductors 

 to be provided, and the total expense of propulsion is said to be a 

 fraction under three halfpence per car mile. For the transmission 

 of energy through long distances the insulated metallic conductors 

 of an electrical system are simple devices when compared with the 

 tubular mains which are required to convey the equivalent power 

 of compressed air; and still greater is the contrast with regard to 

 the facility with which the electric current can be delivered from 

 the main or conductor to the motor of the car, while the car is in 



3— June 20, 1900. 



