HORTICULTURAL SOCIETY OF LONDON. 



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acid, under diflFerent conditions, and he found that those exposed 

 to the fumes of dilute muriatic acid throve and grew luxuriantly, 

 and that even those which had become sickly from the action of 

 mercurial salts, recovered their full vigour when brought under 

 the influence of muriatic acid vapour. When plants are watered 

 with an acid solution, the acid will to a considerable extent, if not 

 entirely, be neutralised by the bases it meets with in the soil j it will 

 combine with the aicalies, earths, or metallic oxides present in 

 the soil, according to the most simple chemical rules, combining 

 with those substances for which it has the most powerful affi- 

 nity. Hence, when plants are watered with muriatic acid, it is 

 plain that the solution must contain muriates of potash, soda, 

 lime, ammonia, &c., and the acid may be valuable as a means 

 of facilitating the absorption of these substances ; but this is 

 mere speculation, because in the present state of our knowledge 

 of the office performed by saline and earthy matters absorbed by 

 plants, it is almost useless to apply ordinary chemical laws to 

 explain the phenomena observed. The fact, however, that mu- 

 riates and similar salts, in which bases are combined with strong 

 acids should be directly absorbed by growing plants and produce 

 good effects, is rather evidence against the view of those, who 

 believe that bases can only assist in the growth of plants when 

 combined with weak acids, such as the carbonic ; and that the 

 presence of strong acids, such as the sulphuric in the organs of 

 plants must immediately prove destructive to them. Bearing 

 however in mind the fact that plants absorb saline substances 

 gradually and in very small quantities, it is easy to understand, 

 that decompositions of a complicated nature, may take place in 

 their organs. 



In experiments on the action of saline manures on plants, there 

 are two thmgs to be considered, viz. the action which they may 

 have on any substance present in the soil, and the state of mecha- 

 nical division in which they are applied ; on the latter circum- 

 stance much of their action will often depend, as it will influence 

 their solubility and absorption by the roots of plants, to a great 

 extent ; thus sulphate of lime may be formed in a soil contain- 

 ing lime, by the addition of dilute sulphuric acid, and the gyp- 

 sum thus formed will be diflFused throughout the soil, and pre- 

 sented to plants in a far more soluble state, than could possibly 

 be effected by artificial means. Some salts, such as the soluble 

 compounds of lime, are very liable to be decomposed by sub- 

 stances present in the soil. As an illustration of this I may- 

 mention the MURIATE OF LIME, or chloridc of calcium. A num- 

 ber of plants of the common Heartsease were watered with a 

 solution of this salt, and after growing for some time were exa- 



