282 APPENDIX TO PART I. 



of lime, but should apply quicklime to the spots over which 

 the manure has been scattered. 



**It is probably in part by setting at liberty the volatile 

 alkali imprisoned in the soil, that quicklime acts so bene- 

 ficially in agriculture, and in particular, that it improves 

 soil containing a free acid, such as peat earth ; for, inde- 

 pendently of its use in neutralizing a substance, which 

 checks vegetation by its antiseptic properties, quicklime 

 may also disengage a portion of ammonia combined with 

 this acid, and thus afford to the plant a more abundant 

 supply of the nitrogen, which it requires. 



** Chloride of calcium, common salt, sulphuric and mu- 

 riatic acids, phosphate of lime, and other salts, may, it 

 would seem, on the principles laid down, be substituted, 

 when gypsum cannot be obtained. 



**The chlorides, indeed, like certain oxides, (such as 

 water and carbonic acid,) seem to be decomposed by the 

 plant under the influence of light, for chlorine is exhaled 

 by vegetables near the sea, as oxygen is in other situations. 

 Hence, if muriate of ammonia should result from the 

 action of common salt upon the carbonate of ammonia 

 present in rain, it may undergo decomposition when ab- 

 sorbed by the plant, and contribute in consequence to sup- 

 ply it with nitrogen. 



*'The above considerations may suggest to us the utility 

 in agriculture of ammoniacal compounds of all kinds, as 

 substitutes for animal manure. 



''Sal ammoniac is probably too expensive an article to 

 be employed ; but sulphate of ammonia may be had of the 

 wholesale chemist at a price considerably more reasonable, 

 namely, at 221. per ton ; and the ammoniacal liquor, which 

 is afforded in abundance by our gas manufactories, through 

 the distillation of coal, is a still cheaper commodity. 



"The latter consists principally of carbonate of ammo- 

 nia, mixed with a certain proportion of the hydro-sulphuret, 

 and, until its use in agriculture was discovered, much of it 

 was allowed to run waste into the Thames, where its nox- 

 ious qualities destroyed the fish, and rendered the water 

 unpalatable and disgusting. 



" Its efficacy as a manure is vouched for by many who 

 have made trial of it upon their land,* and although the 

 hydro-sulphuret of ammonia in a concentrated form would 

 doubtless be fatal to vegetation, yet in a proper state of 



" * See a communication by Mr. Paynter, on Gas-water as a Manure, 

 Eng. Agricult, Journ, No. 1, p. 4." 



