RAMS AND ENGINES 



503 



Hydraulic rams (Ogden). 



The following table gives data as to size, capacity, am 1 cost of hy- 

 draulic rams : 



This table is based on the assumption that the length of discharge 

 pipe is not over 100 feet, and that the head against which the ram 

 works is not over five times as great as the fall of the stream. The 

 drive pipe should always be made as short as the conditions will permit. 

 In winter the ram may be kept from freezing by housing it and pro- 

 viding a small coal fire for the coldest weather. 



Hot-air engines (Ogden). 



The following table gives data of sizes, capacities, fuel cost, of the 

 hot-air engines commonly used : 



