that each one hundred pounds of the required mixture £ood for 



is to contain 4 pounds of available Nitrogen, 8 pounds L_ 



of available phosphoric acid and 6 pounds of available 2 4i 

 potash, we may best determine the amounts of each per 

 ton by multiplying the given figures by 20. Thus:— 



4 x 20 = 80 lbs. Available Nitrogen per ton. 



8 x 20 = 160 " Available phosphoric acid per ton. 



6 x 20 = 120 " Available potash per ton. 



Hence each ton of the mixture is to contain 80 

 pounds of available Nitrogen, 160 pounds of available 

 phosphoric acid and 120 pounds of available potash. 



We next determine the amount of each ingredient 

 necessary to furnish the required quantities of plant- 

 food. Since each one hundred pounds of Nitrate con- 

 tains 15 pounds of Nitrogen, the 80 pounds of Nitro- 

 gen required would represent as many hundreds or 

 fractions thereof, as 1,5 is contained in 80; or 



80 -7- 15% = 533 lbs. Nitrate of Soda 



160 -T- 16% = 1000 lbs. Acid Phosphate 



120 + 50% = 240 lbs. Sulphate of Potash 



Filler 227 lbs. Fine dry loam, or peat, or 



land plaster (gypsum) 



2000 lbs. 



Calculations of Formula of Mixed Materials. 



It is desirable, at times to determine the propor- 

 tions of plant-food in any given mixture. For instance, 

 a mixture is made up of 200 pounds of Nitrate of Soda, 

 200 pounds of tankage, 1,000 pounds of acid phosphate 

 and 200 pounds of sulphate of potash, what is the 

 formula if the Nitrate contains 15 per cent, of avail- 

 able Nitrogen, the tankage 5 per cent, of Nitrogen and 

 10 per cent, of phosphoric acid, the acid phosphate 16 

 per cent, of phosphoric acid, and the sulphate of potash 

 50 per cent, of potash. The amounts of plant food 

 would then be: — 



