“It will be remarked,” says Dr. Vœlcker, “that in the first experimental period, the fermentation of the dung, as might have been expected, proceeded most rapidly, but that, notwithstanding, very little nitrogen was dissipated in the form of volatile ammonia; and that on the whole, the loss which the manure sustained was inconsiderable when compared with the enormous waste to which it was subject in the subsequent warmer and more rainy seasons of the year. Thus we find at the end of April very nearly the same amount of nitrogen which is contained in the fresh; whereas, at the end of August, 27.9 per cent of the total nitrogen, or nearly one-third of the nitrogen in the manure, has been wasted in one way or the other. “It is worthy of observation,” continues Dr. Vœlcker, “that, during a well-regulated fermentation of dung, the loss in intrinsically valuable constituents is inconsiderable, and that in such a preparatory process the _efficacy of the manure becomes greatly enhanced_. For certain purposes fresh dung can never take the place of well-rotted dung. * * The farmer will, therefore, always be compelled to submit a portion of home-made dung to fermentation, and will find satisfaction in knowing that this process, when well regulated, is not attended with any serious depreciation of the value of the manure. In the foregoing analyses he will find the direct proof that as long as heavy showers of rain are excluded from manure-heaps, or the manure is kept in water-proof pits, the most valuable fertilizing matters are preserved.” This experiment of Dr. Vœlcker proves conclusively that manure can be kept in a rapid state of fermentation for six months during winter, with little loss of nitrogen or other fertilizing matter. During fermentation a portion of the insoluble matter of the dung becomes soluble, and if the manure is then kept in a heap exposed to rain, there is a great loss of fertilizing matter. This is precisely what we should expect. We ferment manure to make it more readily available as plant-food, and when we have attained our object, the manure should be applied to the land. We keep winter apples in the cellar until they get ripe. As soon as they are ripe, they should be eaten, or they will rapidly decay. This is well understood. And it should be equally well known that manure, after it has been fermenting in a heap for six months, cannot safely be kept for another six months exposed to the weather. The following table shows the composition of 100 lbs. of the farm-yard manure, at different periods of the year: Composition of 100 Lbs. of Fresh Farm-Yard Manure (No. I.) Exposed in Natural State, at Different Periods of the Year.