260 



Both of which ingredients are highly fertilizing. Whether 

 the insoluble matter mentioned by Mr. Lucas, in the Chalk 

 and Mountain Limestone, consists of the same ingredients 

 and in the same proportion, I am not aware, but it 

 is more probable that it is so than otherwise. The 

 red oxide of iron, existing in the Knottingley and Weldon 

 stone, being in the state of a Peroxide, would also tend 

 to fertilize. I may here remark that the term Magnesian, 

 as applied to all the Limestone coming to the surface 

 between Castleford and Knottingley, appears to me to be 

 a misnomer ; as there are two separate and distinct strata 

 in that district, divided by a seam, some yards in thickness, 

 of red clay, interlaid with beds of gypsum. The upper 

 stratum is thinly laminated, and contains only a trace of 

 carbonate of magnesia, while the lower is in thick beds 

 or blocks, and contains from 30 to 40 per cent, of that 

 substance. In the geological maps I therefore conceive 

 that these two strata ought to be more distinctively marked. 



But to revert to the more immediate object of this 

 paper — " The uses of Lime in Agriculture." The cele- 

 brated chemist, Sprengel, says, " A soil is often neither 

 too heavy nor too light, neither too wet nor too dry, neither 

 too fine nor too coarse : lies neither too high nor too 

 low, — is situate in a propitious climate, — is found to consist 

 of a well-proportioned mixture of clayey and sandy par- 

 ticles, — contains an average quantity of vegetable matter, 

 and has the benefit of a warm aspect and favouring slope : 

 it has all the advantages, in short, which physical condition 

 of climate can give it, and yet it is unproductive — and why ? 

 Because, answers chemical analysis, it is destitute of certain 

 mineral constituents which plants require for their daily 

 food." One of the most important of these mineral con- 

 stituents is Lime. No commonly cultivated vegetable that 

 has yet been analyzed, has been found entirely devoid of 



I 



