236 THE CHEMISTRY OF CATTLE FEEDING 



ABCD and DEFG, represent the relative proportions in 

 which the two foods should be used to produce the N-ratio 

 (6 to i) of the dietary. If the figure is drawn on squared 

 paper, the areas of the rectangles are easily computed. 



This method takes time, and it does not give a very 

 accurate result, but it serves to illustrate the reasoning involved 



10 



FIG. 15 



in the arithmetical method. It can, however, be rendered, at 

 once, simpler and more accurate, as is shown in the following 

 paragraph. 



If the points A and E, on the lines OL and OR, be selected 

 according to the percentages of nutrients in the foods, the 

 straight line joining these two points will be divided at D, 

 in the proportions in which the foods must be taken to give 

 the N-ratio represented by the line ON that of the dietary. 



In the diagram (Fig. 16) the points A and E occupy the 

 same relative positions as the linseed cake and the rice meal 

 in the chart (p. 230) ; and the straight line joining these two 

 points intersects the line ON at D. If the two parts AD and 



