ESSEX SOCIETY. 87 



creases the produce one hundred and ten pounds, and this 

 increased produce of one hundred and ten pounds, is effected 

 by the aid of a little more than four pounds of gypsum, or plas- 

 ter. Another accurate investigator* found, by actual experi- 

 ment, that the ashes of an acre of red clover contain no less 

 than three bushels of plaster of Paris. This important fact 

 proves that the earth already contains a large amount of this 

 substance, and that it is essential to the growth of clover. 

 This may, perhaps, explain why clover so soon runs out, to 

 give place to other grasses. The requisite supply of plaster 

 has been exhausted. In any case, the addition of plaster to 

 clover lands, and especially to pastures, is of the highest im- 

 portance. 



The effect of charcoal is somewhat similar to plaster. Char- 

 coal will absorb ninety times its own bulk of ammonia, which 

 is held from escaping till it is separated by water, and carried 

 into the earth for the plant. When dry, the operation of fixing 

 the gas is repeated, till the next shower sends the gas into the 

 earth, and the particles of water take its place in the charcoal. 

 In this way, as a top dressing, charcoal as well as plaster, per- 

 forms the most important functions. If we take any decaying 

 animal matter, which has begun to give off its offensive and 

 noxious odor, its ammonia, and cover it with charcoal or plaster 

 of Paris, this escaping gas is immediately stopped. No infec- 

 tious odor arises from it. The decay of the substance has 

 suddenly ceased. This simple fact will show the intelligent 

 farmer to what purposes these substances may be applied. His 

 choice of these should depend somewhat on the expense of 

 procuring them. The relative expense depends so much upon 

 circumstances, that we need not make the estimate. As an ab- 

 sorbent and retainer of the valuable properties of manure, 

 peat mud and loam will also be found of essential service. If 

 used on a high and dry soil, the effect of plaster will not 

 be very apparent the first season, unless there are frequent 

 rains. 



There is an impression among many, that plaster does not 

 produce so good results in the immediate vicinity of the sea 



*Davy, Agricultural Chemistry. 



