150 ON THE RATIONALE OF CERTAIN MANURES 



Turnips, for example, g-o a very far way for tlieir food ; and 

 if they exhaust all the manure that is immediately around 

 them, how will they get that which is necessary still to 

 sustain and to comjilete their growth?'" 



Professor Johnston. — Children must he nourished and at- 

 tended to as children ; at first they must he helped to their 

 food, hut in course of time, if properly cared for, they will 

 help themselves, gather flesh, bone, and muscle, and become 

 strong- men. Just so with plants. At first they must be 

 helped to food by placing- it near them ; as they g-et strong 

 they Avill put forth their feelers and take food from a greater 

 distance, and thus nourish and sustain themselves, growing 

 to maturity. My theory implies, that while food is to be 

 placed immediately within the reach of the suckling, there 

 must also be sufficient in its locality generally to supply it 

 with increased nourishment to give it strength ; and this 

 theory practical men have abundantly demonstrated as 

 sound. 



Agricultural Gazette, Sept. 19, 1846. 



Art. XXXV.— on THE RATIONALE OF CERTAIN MANURES 

 EMPLOYED IN AGRICULTURE. 



By Pkofessor Daubeny, of Oxford. 



To afford a rational explanation of the mode in which the 

 substances applied by the farmer to his land cause it to yield 

 more abundant cro})s, cannot be regarded by him as a super- 

 fluous undertaking, more especially when it is recollected 

 that an entire exemption from theory implies a state of mind 

 almost incompatible with the earnest prosecution of any line 

 of pursuit, that the practical farmer is in his own way often 

 the most inveterate of theorists, and that, even if a correct 

 theory did not assist, an erroneous one would be sure to mis- 

 lead us. The proper province, therefore, of the man of 

 science, who attempts to apply his theoretical knowledge to 

 the advancement of agriculture, seems to me to be that of 

 endeavoTU'ing to extract from the statements of practical 

 farmers the ground-work of some rational theory with 

 respect to the uses of the various substances which long ex- 

 perience has led men to employ in the imi)rovement of the 

 soil; thus enabling us to apply them, not, as at present, at 



