May 31, 1889.] 



SCIENCE. 



413 



gency and service stops were made to test the brakes on a slippery 

 rail, all of which were made with great success. The extreme 

 smoothness of the stops, absence of shocks to rear car, the perfect 

 control of the brakes both from the engine and caboose, were 

 noticeable features in this test. 



less than one minute per day. This is on a road about li miles 

 long, having 3J-per-cent grades, operating trains at from 4- 

 minute to li-rainute intervals (since reduced to ij minutes), with 

 a speed of 10 miles per hour. It may be doubted if any road 

 in this or any other country can show a better record. The grips 



,^9_a . 



-RAPID TRANSIT CABLE COMPANY'S GRIP MOTOR. 



CABLE RAILWAYS. 



Cable railways have, where properly constructed, given great 



satisfaction, and the system has steadily grown in favor since its 



introduction on Clay Street, San Francisco, Cal., in 1873. The 



best example of a line of this character for heavy service is to be 



there used consist of two pairs of packed wheels or rollers, set in 

 frames opposite each other. Between these is a pair of solid grip- 

 ping-jaws. The cable is first broilght into contact with the rollers, 

 after which the jaws come into action, and serve as a lock. This 

 grip has these great disadvantages, however : inability to take hold 



FIG 3. — MOTOR WIIH CAB REMOVED 



found on the New York and Brooklyn Bridge, over which passen- 

 gers were first taken Sept. 24, 1883, from which time to May i, 

 1S88, 91,376,778 passengers were carried ; and the delays to traffic 

 due to the cable system amounted in the aggregate to but 20 hours 

 and 46 minutes, — an average per month of only 23I minutes, or 



of the cable except at certain fixed points, or to operate on curved 

 tracks ; and too small contact of the rollers with the cable ; and, 

 to exert the requisite gripping-power on the cable, it must be ap- 

 plied with great force, especially at the time of starting the train, 

 when the greatest power is required, This " pinch " on the cable 



