-----------------------+----------+-------------+-------------+----------- | | | PHOSPHORIC | | | NITROGEN. | ACID. | ALKALIES. | WATER. |-----+-------+-----+-------+---+------- | | |Reduced| |Reduced| |Reduced | | | to | | to | | to -----------------------+----+-----+-----+-------+-----+-------+---+------- |lb. | per | lb. | per | lb. | per |lb.| per | |cent.| | cent. | | cent. | | cent. Horses (winter food) |760 |76 |5 | .50 |3-1/2| .35 | 3 | .30 Cows (winter food) |840 |84 |3 | .30 |2-1/2| .25 | 1 | .10 Swine (winter food) |800 |80 |6 | .60 |4-1/2| .45 | 5 | .50 Sheep (2 lb. hay per | | | | | | | | diem) |580 |58 |7-1/2| .75 |6 | .6 | 3 | .30 -----------------------+----+-----+-----+-------+-----+-------+---+------- From the above table it will be seen that the sheep's dung contains the least percentage of _water_, and is richer in _nitrogen_ and _phosphoric acid_ than any of the other three. The percentage of alkalies, of which the most important is potash, is, however, not so large. This may be accounted for by the interesting and well-known fact that a large percentage of potash is to be found in the wool of sheep.[132] The solid excrement of the sheep is, therefore, weight for weight, the most valuable as a manure, as it contains more nitrogen and phosphates than the others, and at the same time is much drier. If, however, we compare the composition of the solid excreta in a dry state, we shall find that the following are the results (basing our calculation on Stoeckhardt's analyses):-- Nitrogen, Phosphoric acid, Alkalies, per cent. per cent. per cent. Horse 2.08 1.45 1.25 Cow 1.87 1.56 0.62 Pig 3.00 2.25 2.50 Sheep 1.78 1.42 0.71 It will be seen from the above that the dry substance of the solid excreta of the pig is richest in fertilising substances. Too much stress, however, as has already been pointed out, must not be put on any single analysis, as so much depends on various conditions, especially the food.[133] The most reliable method of studying this question, therefore, is to study it in its relation to the food consumed. Wolff has calculated from numerous investigations that, with regard to the amount of solid excreta produced by the food, the following percentage of _organic matter_, _nitrogen_, and _mineral substances_, originally present in the dry matter of the food, is voided in the dung:-- Cow. Ox. Sheep. Horse. Average.