564 POPULAR SCIENCE MONTHLY. 



lie, St. Bernard, and other well-known breeds will occur to every- 

 one as illustrating this psychic plasticity. Doubtless the cat brain 

 is somewhat less impressible, but there would seem to be good rea- 

 sons for including it among the educably variable types. 



WHAT MAKES THE TROLLEY CAR GO. 



By WILLIAM BAXTER, Jk., C. E. 



III. 



A LTHOUGH the electric railway has been introduced through- 

 -^^-*- out the civilized world with the most remarkable rapidity, 

 replacing cable as well as horse roads, there has always been a strong 

 opposition to the use of the overhead trolley, and in some places, 

 as, for instance, the city of Kew York, this opposition has been so 

 strong as to prevent the introduction of the system until some 

 other means of conveying the current to the moving cars was de- 

 vised. Many attempts have been made to solve this problem, and 

 the patents taken out on such devices can be numbered by the hun- 

 dred and possibly by the thousand. Inventors in this field, how- 

 ever, have not met with all the encouragement they could desire, 

 owing to the fact that, notwithstanding opposition, the overhead 

 trolley has been permitted in all but about three or four of the 

 larger cities of this country, and the greater portion of those of 

 other countries. The principal well-founded objection that can be 

 raised against the trolley is that it is unsightly and destroys the 

 appearance of the street, but those who are opposed to it also claim 

 that it is dangerous, and that underground or surface systems would 

 not be. As a matter of fact it is not dangerous, and there is noth- 

 ing on record to show that it is. Many persons have been run over 

 by trolley cars, but this is no fault of the overhead trolley; it is due 

 to the fact that street railroads are permitted to run cars through 

 crowded streets at a speed that is too great for safety. Under- 

 ground conduit cars running at the same speed would run over 

 just as many people. In accusing the trolley of being dangerous 

 it is sought to prove that the current flowing in the wire can do 

 harm; but the history of the numerous roads in existence shows 

 that, so far as human beings are concerned, the trolley current is 

 not fatal, although it can give a decidedly unpleasant shock, such 

 as one would not care to experience the second time. There is 



Note. — Figs. 28 and 32 are reproductions of photographs kindly furnished by the Gen- 

 eral Electric Company, while for the view of car, Fig. 30, we are iiidelited to Colonel N. H. 

 Heft, chief electrical engineer of the New York, New Haven, and Hartford Railroad. 



