548 AMMONIACAL GAS. 



of certain chemical agents present in them ; but other facts seemed to 

 point to some physical property belonging to most soils, in consequence 

 of which they possessed these powers. Mr. Way's experiments show 

 the great absorptive power which the soil has; and give us some 

 evidence of the mode in which this power practically operates. It 

 appears that, if strong liquid manure, or a strong solution of ammonia 

 in water, is filtered through a portion of soO, the ammonia wiU be 

 absorbed, and the liqxiid which passes through will be found to contain 

 no ammonia. It is plain, therefore, that the small quantity of carbonate 

 of ammonia which rain-water usually contains, wiU be absorbed by the 

 surface soil, and that in a very heavy shower of rain, sufficient to render 

 the soil thoroughly wet to a considerable depth, there is no fear that the 

 ammonia thus supplied to the soil will be washed away by the con- 

 tinuance of the rain. "It is also evident," says a writer in the 

 Gardeners^ Chronicle "that, when land is flooded, the ammonia 

 which the water contains will be for the most part arrested by the soil 

 over which it flows. The great fertilising effects produced in Egypt 

 by the waters of the WUe, in its periodical floods, were no doubt partly 

 due to this cause ; the benefit resulting not from the small quantity of 

 slimy mud which the water left behind, but from the saline matters 

 which it brought with it, and which were absorbed and retained by the 

 surface of the soil as the water flowed over it. Mr. "Way's experiments 

 show that a good soil (one which contains a reasonable quantity of clay, 

 which is essential to this effect) has the power of thus absorbing or 

 fixing ammonia in whatever state that substance is presented to it ; it 

 is the same whether the ammonia is in its free and uncombined form or 

 whether it is united to some acid constituting a neutral salt. In the 

 former case the ammonia is directly absorbed, and the water passes off 

 entirely deprived of it ; in the latter case the salt appears to be decom- 

 posed under the influence of this peculiar power of absorption, the acid 

 with which the ammonia was previously combined uniting to lime or 

 some other base present in the soil." 



Wherever animal matters are decaying there ammoniacal gas 

 is evolved. Throvsm into the air in the form of a carbonate, it 

 is immediately dissolved in the vapour eternally present, and 

 when that vapoiu- is precipitated as rain it is conveyed to the 

 earth and to all the foliage that intercepts it. Absorbed by the 

 leaves, sucked up by the roots, it adds intensity to the green 

 colour and vigour to all the powers of vegetation. How it acts 

 is immaterial ; that it does act, and with admirable effect, is 

 now undoubted. 



" The nitrogen of putrefied animals," says Prof. Liebig, "is 

 contained in the atmosphere as ammonia, in the state of a gas 



