1 16 ROUGH-AND-TUMBLE ENGINEERING 



encc and your engine is running 225 revolutions a 

 minute; your belt will be traveling 225x10.5 feefe= 

 2362.5 feet, or very nearly 2400 ft., and if i inch of belt 

 would transmit 3 horse power running at this speed, a 6 

 inch belt will transmit 18 horse power; a 7 inch belt, 

 21 horse power; an 8 inch belt 24 horse power, and so 

 on. With the above as a basis for figuring you can 

 satisfy yourself as to the power you are furnishing. 

 To get the best results a belt ought to sag slightly as 

 it hugs the pulley closer, and will last much longer. 



SOMTHING ABOUT SIGHT-FEED LUBRICATORS 



All such lubricators feed oil through the drop-nipple 

 by hydrostatic pressure; that is, the water of condensa- 

 tion in the condenser and its pipe being elevated above 

 the oil magazine forces the oil out of the latter by just 

 so much pressure as the column of water is higher than 

 the exit or outlook of oil-nipple. The higher the column 

 of water the more positive will be the oil feed. As soon as 

 the oil drop leaves the nipple it ceases to be actuated 

 by the hydrostatic pressure, and rises through the water 

 in the sight-glass merely by the difference of its specific 

 gravity, as compared with water, and then passes off 

 through the ducts provided to the parts to be lubricated. 



For stationary engines the double connection is pre- 

 ferable, and should always be connected to the live 

 steam pipe above the throttle. The discharge arm 



