532 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



committee was 1.25 meters in height, by 0.8 meters square, 

 and wei2:hed about a ton. In it three movable electro-maor- 

 nets revolved between the poles of three fixed electro-mag- 

 nets ; one of these developed the magnetism of the fixed 

 masrnets, the otlier two furnished the lisrht. The fixed mair- 

 nets were wound with 250 kilogrammes of wire, the movable 

 ones with 75 kilogrammes. With a velocity of 300 rotations 

 per minute, requiring four-horse powers of force, this ma- 

 chine gave a tension equal to that of 105 ordinary Bunsen 

 cells, and a quantity of five such cells ; it gave a light equal 

 to that of 900 Carcel gas-jets ; and it ignited 12 meters of 

 copper wire 0.7 of a millimeter in diameter, and five meters 

 of iron wire 1.3 millimeters thick. It fused 2^ meters of this 

 latter wire. Annales cle Chim. et de Phys.^ IV., 324. 



RECENT EXPERIMENTS WITH THE WESTINGHOUSE AIR BRAKE. 



A very thorough experimental trial of the Westinghouse 

 Air Brake, as recently modified and improved, has lately 

 been made by a scientific committee of the Franklin In- 

 stitute, the record of which is worthy of being at least 

 briefly alluded to. The exj^eriments in question were made 

 with a special train of seven cars upon that portion of the 

 Pennsylvania Railroad which lies between Philadelphia and 

 Paoli. The first signal to stop was given by the conductor 

 by means of the bell-rope, while the train was going at the 

 rate of thirty miles per hour, and the train was brought to 

 a full stop in sixteen seconds, passing over 503 feet of rail. 



Another stop was made by applying the brake from the 

 interior of one of the cars by a cord passing over the win- 

 dows and attached to valves of the apparatus. The train, 

 making thirty-five miles per hour, was stopped in fifteen sec- 

 onds, and passed over 514 feet of rail from the time of the 

 signal to stop. In all cases the distance was determined 

 from a flag thrown out when the brake was applied. Several 

 interesting experiments were t-lien made by severing the 

 train, the act of uncoupling causing the brake to be applied. 

 The five rear cars were separated while running at the rate 

 of thirty -two miles per hour, and in fifteen seconds were 

 brought to a full stop by the automatic action of the brake, 

 passing over 367 feet of rail. Again, the engine was sepa- 

 rated Avhile the train was making forty-five miles per hour. 



