IGO ON THE THEORY AND 



and tliat of liberating- potash from rocks and clays, are very 

 imj^ortant ; but they have little or no reference to the one 

 which appears to be still more extraordinary. 



Some years since, the theory of humus was broached ; and 

 for a time the cultivators of the ground were taught to con- 

 sider it the all-in-all, the pabulum of nutrition, '' the chief 

 nonrisher in life's feast 5" or, in other and more homely 

 terms, '^ the cooked food of plants." Soon, however, the 

 zeal of its partizans was checked, and then it appeared that 

 humus was a slowly formed product of vegetable decay, and 

 that, so far from being a wholesome food, its predominance 

 became a medium of barrenness and destruction. Peat bogs, 

 flow-mosses, and, indeed, all submerged masses of vegetable 

 matter, abound with humus ; and these, so long- as they 

 remain in their natural condition, are worthless, and unpro- 

 ductive of good cerial or garden crops. Lime, duly applied 

 in tillage, is the grand chemical remedy ; it exerts a specific 

 action not at all connected with an}' solvent power, and this 

 has been clearly and unequivocally explained by Mr. Row- 

 landson of Liverpool. He has entered into a minute chemical 

 detail of facts, and has shown, b}' irresistible evidence, that 

 his theory of the remedial action of quick-lime is correct. 

 Mr. Ruffin, of the United States, had paved the way for 

 new researches into the agency of calcareous manures, and 

 his able articles were copied into the pages of the British 

 Farmer-' s Ilagazine of 1835. 



Since the appearance of Rowlandson's article, I entered 

 into several interesting- experiments, a detail of which will 

 substantiate the view taken by that gentleman of the che- 

 mical action of lime. 



There are two or three substances which fairly represent 

 humus. The first is, the dark-coloured mass that remains 

 after long-protracted fermentation of the dung mixen, and 

 long after it has attained the state of Avhat is termed " spit- 

 dung." The second, the dark brown remains of the bottom 

 of a very old wood pile. The third, completely reduced 

 leaf-mould, or that peculiar modification of moor-soil which 

 is occasionally found in some heath commons. All these 

 substances can be procured for experiment, and will furnish 

 proof of the singular agency which lime must exert upon 

 vegetable remains when reduced to the condition of 

 humus. 



If to a solution of caustic potash, soda, and particularly of 

 ammonia, a portion of either of the afore-named matters be 



