388 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



importance expected to flow from it. It is expected, for in- 

 stance, that the tunnel will form the great highway or out- 

 let for the ores of the Comstock, which are at present hoist- 

 ed to the surface, and thence transported to the mills on 

 the Corson River, a distance of some twenty miles. By the 

 erection of mills at the mouth of the tunnel, the cost of 

 transportation (which is now very considerable) could be 

 greatly reduced. It will also render possible the profitable 

 working of low-grade ores, of which enormous quantities re- 

 main in the mines untouched. 



Work on the tunnel was commenced on October 19, 1869, 

 and has been steadily continued until the present, when but 

 little more is required to complete it. The total amount ex- 

 pended on the work thus far will foot up to about 83,000,000. 

 Some $500,000 more will be required, on completion of the 

 tunnel work, to provide it with a double track, and bring 

 it into complete working order with the paraphernalia for 

 wire-rope transmission, etc. 



STEAM-MOTORS ON CITY RAILWAYS. 



In addition to the satisfactory progress made during the 

 past year towards the completion of the elevated -railway 

 plant, designed to secure rapid transit in New York City, 

 the substantial progress made in other cities in introducing 

 steam-cars on the street-railways is worthy of special notice. 

 This movement was inaugurated by the Market Street City 

 Passenger Railway Company of Philadelphia, which in the 

 month of March, 1877, put into operation seven steam-cars, 

 with the avowed purpose of giving them a thorough and 

 continuous practical test. The experiment appears up to 

 the present time to have proved quite successful, as all the 

 cars have continued in operation since they were put on 

 without difficulty or objection. The cars are noiseless in 

 operation, and the anticipated trouble from the escaping 

 steam has proved to be groundless. The operation of these 

 ears has shown, it is affirmed, a notable economy over the 

 common plan of horse traction which they replace. The 

 success of this experiment appears to have attracted atten- 

 tion to the question, and a considerable number of steam- 

 cars have been introduced during the past year upon the 

 street-railways of other American cities. 



