902 ANNUAL ItEPUK'l OF THE Off. Doc. 



of the chop or 127.8 pounds too little in the entire 90 cwt. The ex- 

 cess protein in the bran, having a guaranty percentage of 15.2 per 

 cent, is 4.2 pounds per cwt. To supply 127.8 pounds of such excess 

 would therefore require 127. 8-^-4.2, or 30.43 cwt. of liie bran. The 

 guaranty percentage of fat in the bran being 4 per cent, the bran 

 would supply 121.7 pounds of fat; this added to the 368 pounds of 

 the chop, would make 481). 7 pounds in the mixture; since the latter 

 has a weight of 0,000 plus 3,013 pounds, or 12,043 pounds, the per- 

 centage of the fat in the mixture must be 4.07 per cent. 



4. The mixer has, however, more complex problems. It is often 

 needful to determine not only how much but what kind of a bal- 

 ancing material to use in a brand of feeding-stufl; whose main mate- 

 rials are already fixed, though i( may be that the main ingredients 

 may be varied in proportion according to the circumstances of sup- 

 ply and cost, which also affect the selection of the balancing mate- 

 rial. Sometimes, too. it is desired to prepare a mixture which shall 

 have not only a fixed percentage of portein, but of fat as w^ell. In 

 both sets or problems, the unknown quantities are too numerous 

 to allow the -formulation of any simple rule of calculation. The 

 mixer must try, one after another, such a succession of j»roportions 

 and ingredients as he may regard likely to meet his need, until he 

 shall succeed in finding a combination nearly such as he desires. 

 In each trial, however, he will find the methods already given, use- 

 ful for his purpose. 



