Nf) C DEPATxTMlON'!" 01' ACRICIILTIIHE. 9ul 



r"/. I'd calculate the (quantities in lokich to conihine. certain inyre- 

 ditnts of deter iiiined composition so as to make a mixture of a (firiu 

 Composition: lu the lirst place, let the lixed itoiiit in the mixture be 

 its perceutuj^e oi' but one ui' those constituents i-e(iuiied to be named 

 in the guaranty; protein may be taken, since it is the most evi)en- 

 sive component, that lor which concentrated feeds are chiell.v son^;lit 

 and, at the same time, that which is most variable in percentage in 

 the various ingredients used for mixing. 



The simplest pi\)blem of this sort, is to determine the proportions 

 in which to mix two known feeds to secure a mixture containing a 

 given protein percentage. The percentage in the mixture must, of 

 necessity, lie between those of the ingredients. Let the (piestion 

 be in what proportions to mix corn meal and pure buckwheat mid- 

 dlings, pure, so as to obtain a mixture having 14 per cent, of protein. 

 The guaranty percentages of the two ingredients are: ('orn meal, 8.1 

 per cent, protein, 2.1) per cent, fat; buckwheat middlings, 27 jx-r 

 cent, protein, 6.4 per cent. tat. Since the term per cent, means sim- 

 ply parts per bushel, it follows that lUO pounds of the two ingredi 

 ents will contain, respectively, 8.1 and 27 pounds of protein, while 

 every hundredweight of the mixture s'hould have 14 pounds. That 

 is, every hundredweight of corn meal w ill bring 5.9 pounds too little, 

 while the same weight of buckwheat middlings will contribute an 

 excess of 13 pounds. Obviously, only so much of the buckwheat 

 middlings should be mixed with one hundredweight of the corn meal 

 as will balance, by the protein it contributes in excess of the re- 

 quirement, the deiiciency of the corn meal. Since 100 pounds of 

 middlings contains an excess of 13 pounds of protein, to supply an 

 excess of 5.0 pounds of protein will require but 5.0-13 of 100, or 45.4 

 pounds of the middlings. The mixture should therefore contain 45.4 

 pounds of the middlings for every hundredweight of the meal used. 

 From the fat percentages given above and these proportions of the 

 ingredients, it can be calculated by the method stated for the second 

 class of problems, that the guaranty percentage of fat in this mix- 

 ture would be 3.02. 



A very similar problem is that in wliidi it is desired to ascertain 

 in what proportions to use a higlily nitrogenous material to bahince 

 up a mixture of less rich feeds whose quantities are already deter- 

 mined. Suppose, for example, that a mixer, having a corn and oats 

 cho]) composed of 5,000 pounds of corn and 4,000 pounds of oats, de- 

 sires to determine how much sjjring wheat bran must be added to 

 liiodnce a mixture having 11 i)er cent of })rotein. The calculation of 

 problem two has shown that the 00 cwt. of mixed chop contains 802 

 pounds or 0.58 per cent, of jjrotelu and 308 ])ounds or 4.00 per cent, 

 of fat. That is, the corn and oats alone foini a mixture having 11 

 minus 0.58, or 1.42 pounds too little protein for every hundredweight 



