261 



this ingredient ; and we may therefore, I think, reasonably 

 conclude that it is an essential, in order to produce a 

 properly developed plant ; in fact, that it is one of the 

 substances which constitute its necessary food, and help 

 to build up its frame. To insist upon growing plants, 

 into whose structure Lime largely enters, upon land devoid 

 of that esssential, is something similar to the conduct of 

 the mother that I lately heard of, who, when her child 

 was about forming its teeth, in order to give it strength, 

 fed it entirely upon arrow root, supposing that diet to be 

 the most nourishing. Now arrow root contains only the 

 elements of fat, and not of bone and muscle. It affords 

 no phosphoric acid and Lime. The child therefore con- 

 tinued ricketty, and could form neither bone nor teeth. 

 Immediately that the diet was changed, and food containing 

 those necessary ingredients was administered, the desired 

 result took place, and the child soon became strong and 

 healthy. 



According to Professor Johnston, a common four-years 

 rotation of crops, that is — Turnips — Barley — Clover and 

 Wheat — extracts from the land, and consequently there 

 requires to be supplied, during the four years, 288 pounds 

 of pure Quick Lime, or about 524 pounds of the Carbonate 

 — the turnips and the clover, or the two green crops, 

 needing at least 9-lOths of the whole. Viewing Lime, 

 then, as one of the essential constituents of plants, we 

 must acknowledge the necessity of its presence in the soil, 

 even if its being food for the crop, only, were taken into 

 account, without considering its other uses, which I shall 

 shortly touch upon. Hence we also see how essential is 

 its artificial introduction into the soil, where it does not 

 already naturally exist in sufficient quantity. Sir Humphrey 

 Davy, in his Agricultural Chemistry, enumerates many 

 fertile soils, of which he gives the analysis, and in none, 



