OF FARMYARD MANURE. 103 



phuric acid, or a few pounds of plaster, may be occa- 

 sionally thrown in. The sulphuric acid will unite 

 with the ammonia, and form sulphate of ammonia, 

 which will remain unchanged, not being liable to 

 evaporate. Others prefer to mix sufficient peat, ashes, 

 sawdust, or fine charcoal, with the liquid in the tank, 

 to soak it all up; others still pump it out and pour it 

 upon a compost heap. One point is to be noticed in 

 the management of a tank. Only the water which 

 naturally drains from the stables and yards should be 

 allowed to enter it: all that falls from the eaves of 

 the buildings should be discharged elsewhere. Regu- 

 lated in this way, the tank will seldom overflow, and 

 the manure collected in it will be of the most valua- 

 ble and powerful description. The tank may be made 

 of stone, brick, or wood, as is most convenient, and 

 need cost but very little. 



While the liquid manure is actually in many cases 

 almost entirely lost, the solid part is often allowed to 

 drain and bleach, until nearly every thing soluble has 

 washed away; or is exposed in heaps to ferment, with- 

 out any covering. In such a case ammonia is always 

 formed and given off: it may often be perceived by 

 the smell, particularly in horse manure. The fact may 

 also be shown, by dipping a feather in muriatic acid 

 and waving it over the heap. If ammonia in any 

 quantity is escaping, white fumes will be visible about 

 the feather, caused by the formation of muriate of 

 ammonia. A teacher can exemplify this by holding 

 a feather, dipped in the same way, over an ammonia 

 bottle. This escape of so valuable a substance may be 

 in a great measure prevented by shovelling earth over 

 the surface of the heap, to a depth of two or three 

 inches. If this does not arrest it entirely, sprinkle a 

 few handfuls of plaster upon the top: the sulphuric 

 acid of the plaster will as before unite with the am- 

 monia, and form sulphate of ammonia. 



