128 



[Assembly 



These machines are so similar in their power of separating 

 grain from straw, that any preference must arise from other con- 

 siderations. 



The cylinders all revolve at so high a rate of speed it becomes 

 important to protect the journals from the gritty particles of dust 

 which are always flying in profusion while thrashing ; thorough 

 lubrication is also essential. To secure these desirable ends, in- 

 ventors have provided special contrivances ; they cover the ori- 

 fices for lubrication with close fitting tin covers to exclude grit 

 and dust. In some instances a candlewick passes through a 

 tube in the box which at one end touches the journal, and at the 

 otber communicates with a cup-shaped cavity on the box, filled 

 with oil, from which cup it passes to the journal by capillary at- 

 traction. This contrivance was used by Westinghouse and 

 worked well, while the machine was under examination. Tal- 

 low was used on Pitts' machine, being placed within a collar on 

 the upper box, covered by the tin cap ; a straw is thrust through 

 the tallow to the journal. Through this hole thus made oil is 

 poured for lubrication. If by neglect the supply of oil is defi- 

 cient, the journal becomes heated, melting the tallow, and for 

 the time perfect lubrication ensues. These contrivances are 

 among the best presented, to guard against negligence ; but the 

 farmer must esteem them only as expedients never to be relied 

 on for the preservation of his machinery : due attention and uni- 

 form application of substances to lessen friction, are not to be 

 omitted with impunity. 



