Manures purchased annually in England.
--Prof. Anderson gives the following estimate of the amount expended annually by the farmers of Great Britain for artificial manures:
Guano | $12,500,000 |
Nitrate of Soda | 1,125,000 |
Bones | 1,200,000 |
Super phosphates | 2,100,000 |
Coprolites | 1,875,000 |
Sulphate of Ammonia | 750,000 |
Other Articles | 500,000 |
Total | $20,950,000 |
This expenditure, coupled with improved methods of tillage, accounts for the fact that the average product of wheat in England has been raised from 8 or 9 bushels to nearly 30 bushels per acre.