August 21, 1885.] 



SCIENCE, 



149 



direction, and insuring perfect accommodation, 

 on the part of the motor, to any irregularities 

 in the road-bed. 



The connection with the middle rail is made 

 b}' means of a heavy bronze wheel fourteen 

 inches in diameter B. This being fastened to 

 an arm, may be raised or lowered, thus allowing 

 discontinuities in the central rail, of which 

 there are several in the Ninth-avenue line, to 

 be safely passed. The wiring is all underneath 

 the frame, and is enclosed in wooden sheath- 

 ing. The device for controlling the motor is 

 placed at the end of the cab at E. This is a 

 device of sliding contacts, worked by a handle 

 similar to the throttle in the loco motive- cab, 

 which raises or lowers the resistance in the 

 field-magnet circuit, thus var3'ing the amount 

 of current, and consequently the strength of 

 field and speed of motor. There is also a 

 complete cut-out in circuit. The motor is thus 

 under complete control, it being possible to 

 run fast or slow. The motor ma}^ be stopped 

 either Iw the cut-out, or b}^ lifting the contact- 

 wheel. The s^^stem is further jn'ovided with 

 an automatic cut-out, which breaks the circuit 

 when the current reaches a certain strength, 

 at the same time ringing a bell at the central 

 station, warning the engineer at the central 

 station that there is trouble on the road. 



The reversing-gear is simpl}- four brushes 

 connected bj^ suitable links, so that a move- 

 ment in one direction applies one pair of 

 brushes, while a movement in the other applies 

 the opposite pair. In the motor Benjamin 

 Franklin, the ordinary hand-brake will be 

 emplo3'ed ; but later, some form of air or 

 electric brake will be used. This motor is a 

 very substantial affair, as its weight (nine 

 tons) would show. The experiments will be 

 performed as soon as Mr. Daft is at leisure 

 to commence them. 



The Edison and Field companies have com- 

 bined, and are preparing to test their system 

 upon the Second-avenue line. The length of 

 this line from Chatham street to Harlem is 

 7.44 miles, onh^ part of which, however, will 

 be traversed by the electric railway. Although 

 this company have not brought their work so 

 near completion as the Daft company, still 

 they have done a deal of hard work. They 

 have located their central station upon 24th 

 Street, and have provided there a two hundred 

 and fifty horse-power Whitehill & Smith en- 

 gine, with the necessary boilers and shafting. 

 The Edison dynamos have not yet been set in 

 position, nor has any wiring been done. 



In this system, the central rail has to be very 

 carefulh' insulated on account of the compara- 



tively high electro-motive force employed (some 

 six hundred volts). To this end, the rails will 

 be insulated b}' resting upon glass shoes, whicli 

 will be protected from the jar of passing trains 

 b}" a thin strip of rubber. As the glass shoes 

 have not been delivered, the rails have not 

 been laid. 



The work upon the motor has progressed 

 slowly on account of the man}' difficulties 

 offered. The original arrangement shown in 

 the New-York worlds April 26, 1885, has given 

 way to several newer forms suggested b}' it. 

 The latest form, and the one to be completed, 

 is shown in the schematic drawing (fig. 2). 



In this sj'stem, every truck will be provided 

 with a motor, thus making every car independ- 



FiG. 2. 



ent. In fig. 2, ^ is the bottom of the car, T 

 is the ordinary railway truck used upon an}' 

 car. To apply the motor, the truck is pro- 

 longed to B, and is supported by the spring S. 

 This spring is hung from a roller capable of 

 side motion, thus allowing the truck to accom- 

 modate itself to curves. The motor used is a 

 compound- wound Siemens, and is so designed 

 that, with an external electro-motive force of 

 six hundred volts, it will revolve at a constant 

 speed of six hundred revolutions per minute. 

 The power is transmitted from the armature to 

 the pulley C by means of a Weston friction- 

 clutch. This friction-clutch TFis worked by a 

 wheel similar to the ordinary brake-wheel, one 

 wheel working both friction-clutches of one 

 truck. The power is transmitted from the 

 pulley C to the pulley P, keyed to the axle of 

 the driving-wheels by means of a heavy leather 

 belt of peculiar construction. In order to ob- 

 tain more bearing-surface for the belt, it is 

 carried around the pulley B. This same ar- 

 rangement is reproduced on the other side of 

 the truck. 



The motor itself is movable, so that the ten- 

 sion of the belt may be varied at will. The 

 contact with the middle rail is made by means 

 of brushes sliding upon it. The brushes are 

 mounted on the ends of a bar which prevents 

 their dropi)ing down when another road is 

 passed, and thus short circuiting the track. 

 The brushes are held in position by springs 

 which allow them to turn, and thus insures a 

 drag of the brushes at all times, instead of 



