HORSE-POWERS. 1 1 5 



set-screws. This will prevent the pipe from turning in 

 these castings. The pipe is countersunk for the set-screws 

 in 2ioW, these set-screws being tightened at the factory. 

 The key with straps should be nailed to the driver's platform. 

 This is used to prevent the brake from dropping onto the 

 wheels when not wanted. The brake is applied by the foot. 

 Do not press the ratchet down harder than necessary. 



The Spur-Wheel and Bull-Pinion Shafts. The key- 

 seats of these shafts are cut in line with each other and 

 



those in the bull-pinions and inside-pinions are cut with 

 reference to one of their teeth so that when the pinions are 

 keyed to the shaft, their teeth will be in line. It will be seen 

 that if the shaft has been twisted so that the teeth of the 

 pinions are even slightly out of line, the power cannot be 

 made to run properly. A new spur-wheel shaft is the only 

 remedy for such a condition. 



Work Done by Horses. The sweeps of the twelve-horse 

 power and smaller sizes are twelve feet and seven inches 

 long, and their ends move in a circle the circumference of 

 which is seventy-nine feet. The sweeps of the fourteen- 

 horse power are fourteen feet long, and their ends move in 

 a circle, the circumference of which is eighty-nine feet. 

 Horses ordinarily travel around the seventy-nine foot circle 

 two and one-half times a minute, and around the eighty-nine 

 foot circle two and one-fourth times a minute, in either case 

 covering about two and one- fourth miles per hour. The term 

 "horse-power" (the standard measure of power) is defined 



