Food for The statements of guarantee-analysis as used by manu- 



Pltnt> facturers differ considerably in form, and the amount of 

 *9 6 each constituent is usually stated as being between two more 

 or less widely varying limits. Thus, we are offered a fer- 

 tilizer which in the guaranteed analysis is stated to contain : 

 Ammonia, from 2 to 3 per cent. ; available phosphoric acid, 

 8 to 10 per cent; insoluble phosphoric acid, 2 to 3 per cent; 

 and potash, equal to 3 to 5 per cent. In estimating the valua- 

 tion from such form of statement of analysis the lower 

 numbers should be always used, for the manufacturer is held 

 legally only to the lower figures given in the guarantee. The 

 per cent, of Nitrogen in the guarantee-analysis is most usually 

 given in the form of ammonia, and the per cent, of potash 

 may be given in the form of sulphate or muriate (chloride) 

 of potash. When the per cent, of organic Nitrogen is given 

 multiply the per cent, of Nitrogen by the trade value adopted 

 for organic Nitrogen in mixed fertilizers. But if the Nitro- 

 gen is stated in the form of ammonia, multiply the guaranteed 

 per cent, of ammonia by .8235, which will give the per cent, 

 of actual Nitrogen ; then multiply the result by the trade value 

 for organic Nitrogen in mixed fertilizers, which will give the 

 value of the Nitrogen in 100 pounds of fertilizer. Thus, in 

 the fertilizer given above the per cent of ammonia in the 

 guaranteed analysis is from 2 to 3 per cent. As directed, we 

 take the lower number, 2 percent.: 2X-8235=i.65 percent, 

 of Nitrogen; i.65X!5/^ cents=25.58 cents. 



The per cent, of available phosphoric acid is guaranteed 

 to be from 8 to 10 per cent: 8X4/^ cents=36 cents. 

 Insoluble phosphoric acid: 2X 2 cents=4 cents. 



The guaranteed per cent, of potash is 3 to 5 per cent. 

 But the statement of analysis does not tell the form in which 

 the potash is present. All we know is that there is from 3 to 

 5 per cent, of actual potash contained in the fertilizer, so we 

 will give ourselves the benefit of the doubt and assume the 

 potash to be in the form of muriate (chloride) : 3X4/^2 

 cents= 1 3 /2 cents. 



We now have the value in cents of the Nitrogen, avail- 

 able and insoluble phosphoric acid, and potash. Add these 

 together and the sum is the value in cents of the total fertiliz- 

 ing constituents in 100 pounds of fertilizer. This sum mul- 

 tiplied by 20 gives the value in cents of one ton. 



