COTTON 131 
buying factory mixed goods by the guaranteed 
analysis and not by any particular name or brand. 
Nitrogen is usually about three times as costly 
as phosphorus and potassium. The prices of 
these elements vary from year to year, but in a 
general way one can place the commercial value of 
nitrogen at fifteen cents per pound and _ phos- 
phorus and potassium at five cents Be pound. 
In computing relative values of different fertilizers 
you should bear in mind that 1 per cent means 
one pound in a hundred, or twenty pounds in a ton. 
It is also a good plan to base your estimate on the 
lowest percentage figure, since these more truly 
represent the true value; the higher ones are 
usually put there to deceive the purchaser. 
To show the manner of estimating fertilizers, I 
will use two brands commonly sold on the market: 
No.1. Guaranteed Analysis. 
Nitrogen 1.60 to 2 per cent. 
Phosphoric acid 7 to 8 per cent. 
Potash, 2 to 2.75 per cent. 
Cost, $30.00 per ton. 
When these percentages are multiplied by 20 we 
obtain the number of pounds in a ton, and when 
further multiplied by the value per pound, we 
obtain the value on the basis of a ton. 
This is shown below: 
Nitrogen 1.60 by 20= 32 lbs. @l5c. = $4.80 
Phosphorus 7 by 20=140 lbs. @ 5c. = 7.00 
Potassium 2 by 20= 40 lbs. @ 5c. = 2.00 
Commercial value per tor.......... $13.80 
