572 POPULAR SCIENCE MONTH I. Y. 



the brushes h b is not required. To avoid the accumulation of 

 water in the conduit the drain G is provided with outlets d, located 

 at suitable points. 



Although this system is the simplest that can be devised for use 

 in streets or public highways its construction is very costly, so much 

 so that it can only be used in cities where the traffic is so great 

 as to require the running of cars on short headway; and, further- 

 more, it can not be operated with any degree of success except in 

 municipalities where there is a good sewage system. During the 

 summer months it is liable to be more or less impaired by heavy 

 showers, but the trouble in such cases is only temporary. In 

 winter time snowstorms are liable to affect it in the same way, 

 especially if, after a heavy fall, a warm wave comes along and 

 produces a rapid thaw. 



From the fact that no attempt whatever is made to protect the 

 conductors, one would naturally suppose that every time there is 

 a rain the road would be compelled to shut down; for, as the slot 

 through which the plow travels is open, water can enter the con- 

 duit with the greatest freedom, and, in trickling down the sides, 

 would be caught to some extent upon the brackets c c, and thus 

 make its way over to the channel bars a a, and thereby destroy the 

 insulation. Practice, however, shows that this action does not take 

 place, at least not so often as to produce any serious trouble. The 

 roads that are operated by electricity in New York, and also the 

 lines of the Capital Traction Company, of Washington, D. C, 

 employ this system, and they have been in operation a sufficient 

 length of time to fully demonstrate that the difficulties actually 

 developed by the action of the elements are not of a formidable 

 character. On one occasion the Sixth Avenue road, in New York, 

 was compelled to stop its cars for a short time just after a severe 

 snowstorm, but the failure was not due to impairment of the 

 insulation, according to the statements of the officials of the com- 

 pany, but to the fact that the melted snow froze upon the track 

 and caused the wheels to slip around without sending the car ahead. 

 The fact that other roads in New York, belonging to the same com- 

 pany, are being ((piippod with the system, is proof that, upon the 

 whole, its practical operation is regarded as satisfactory; but it is 

 very evident that it is not the final solution of the problem. A 

 system to be a decided success must cost very little more than the 

 ordinary overhead trolley, and its construction must be such that 

 it will not easily get out of order. If it is not inexpensive it will 

 not come into use except in places where the authorities will not 

 permit the overhead wires. A surface or underground system 

 ought to be more durable than the overhead, as the wires are not 



