Dr. Vœlcker made still another experiment. He took 1,613 lbs. of well-rotted dung (mixed manure from horses, cows, and pigs,) and kept it in a heap, exposed to the weather, from December 5 to April 30, August 23, and November 15, weighing it and analyzing it at these different dates. I think it is not necessary to give the results in detail. From the 5th of December to the 30th of April, there was no loss of nitrogen in the heap, and comparatively little loss of soluble mineral matters; but from April 30 to August 23, there was considerable loss in both these valuable ingredients, which were washed out of the heap by rain.
Dr. Vœlcker draws the following conclusions from his experiments:
“Having described at length my experiments with farm-yard manure,” he says, “it may not be amiss to state briefly the more prominent and practically interesting points which have been developed in the course of this investigation. I would, therefore, observe:
“1. Perfectly fresh farm yard manure contains but a small proportion of free ammonia.
“2. The nitrogen in fresh dung exists principally in the state of insoluble nitrogenized matters.
“3. The soluble organic and mineral constituents of dung are much more valuable fertilizers than the insoluble. Particular care, therefore, should be bestowed upon the preservation of the liquid excrements of animals, and for the same reason the manure should be kept in perfectly water-proof pits of sufficient capacity to render the setting up of dung-heaps in the corner of fields, as much as it is possible, unnecessary.
“4. Farm-yard manure, even in quite a fresh state, contains phosphate of lime, which is much more soluble than has hitherto been suspected.
“5. The urine of the horse, cow, and pig, does not contain any appreciable quantity of phosphate of lime, whilst the drainings of dung-heaps contain considerable quantities of this valuable fertilizer. The drainings of dung-heaps, partly for this reason, are more valuable than the urine of our domestic animals, and, therefore, ought to be prevented by all available means from running to waste.
“6. The most effectual means of preventing loss in fertilizing matters is to cart the manure directly on the field whenever circumstances allow this to be done.