ON THE THKORY AND PRACTICAL USE OF LIME. 159 



Art. XXXVL— on THE THEORY AND PRACTICAL USE 

 OF LIME. 



By Mr. J. Toavers. 



About tlie time that Liebig's first work appeared, I, witli 

 others, only endeavoured to show that, in order to decompose 

 siirphis or crude veg-etable matter, and hberate its elements, 

 lime must not onh' attract the moisture, or free water of the 

 lierbag-e, but must disturb the chemical affinities of the 

 elements which compose its tissue, so as to liberate the 

 hydrogen and oxygen, causing' them to re-combine as water, 

 and to deposit the carbon in the form of black charcoal ; in a 

 w^ord, that it must produce chemical combustion — without 

 ig-nition indeed, but nevertheless true in its results. 



But while the theory, so far as it went, may be certain, 

 we must premise that the lime so to act must be pure and 

 unslaked, or in that very condition wherein we find it when 

 it absorbs and combines with water, in the act of slaking* ; 

 otherwise it can never burn and consume the veg'etable 

 matters, even if applied to the extent of from four to eig'ht 

 hundred bushels per acre. Independently, therefore, of its 

 mere destructive power, |)ure lime, that is to say, lime free 

 from carbonic acid, whether fresh from the kiln, or slaked by 

 air or water (i. e., in the condition of hydrate), must and 

 does exert a chemical action peculiarly specific, and of vast 

 importance to the agriculturist ; and this I shall endeavour 

 to render experimentalh' evident, after quoting- one leading* 

 passage from the paper of Dr. Daubeny. It reads thus — 



" Its effect in rendering the org-anic matters more soluble, 

 or rather, as I should prefer to represent it, in promoting* 

 their decomposition so as to render them better adapted for 

 supplying' both carbon and nitrog-en to g-rowing' plants, has 

 been already sufficiently explained by Professor Johnston 

 and by others. Yet when we recollect that quick-lime, 

 mixed with pounded granite, speedily liberates the contained 

 alk-ali, and that many of the clays and claystones which 

 compose the bulk of several rock formations in secondary 

 and tertiary districts are derived from granitic rocks, we 

 cannot doubt that the action of quick-lime upon the latter 

 will be of analogous description." 



These qualities of lime, that is to say, its solvent power, 



