Phosphoric acid is often stated as "bone phosphate" because in this the amount appears to be greater.
For example, an analysis taken from a fertilizer catalogue reads as follows:
| Ammonia | 2 to 3 per cent. |
| Available Phosphoric Acid | 8 to 10 per cent. |
| Total Phosphoric Acid | 11 to 14 per cent. |
| Total Bone Phosphate | 23 to 25 per cent. |
| Actual Potash | 10 to 12 per cent. |
| Sulphate of Potash | 18 to 20 per cent. |
A better statement would be as follows:
| Nitrogen | 1.65 per cent. |
| Available Phosphoric Acid | 8 per cent. |
| Total Phosphoric Acid (furnished in Bone Phosphate) | 11 per cent. |
| Potash (furnished in Sulphate of Potash) | 10 per cent. |
Ammonia is reduced to terms of nitrogen by multiplying by .824. All bone phosphate is forty-six per cent. phosphoric acid. When bone phosphate is given instead of phosphoric acid it simply makes the mixture appear to have more in it, and when both phosphoric acid and bone phosphate are stated one is merely a repetition of the other. The same is true of the statements, potash and sulphate of potash, one is a repetition of the other only a different form.
VALUATION
The experiment stations not only publish comparative analyses of the registered fertilizers but they also compute the market values of the plant food contained in them and compare these valuations with the selling price of the fertilizers.
They also furnish a list of trade values of the plant foods in raw materials for the convenience of fertilizer buyers in testing the values of the brands offered them on the markets.