of Science to Agriculture. 145 



of those solid ingredients contained in his crops, of which the 

 soil possesses only a limited quantity ; as likewise the weight of 

 the same which was present in the manure that had been added 

 to them. 



But as an actual analysis of his crops, though by far the most 

 accurate method of attaining such knowledge, would involve a 

 degree of labour and science which few agriculturists could afford, 

 it seems desirable that tables should be drawn up of the ingre- 

 dients existing in all our ordinary crops, compiled from the best 

 authorities that can be obtained. A specimen of such a table, 

 which I have myself constructed for this purpose, stands now in 

 the room under the title of " Agricultural Constants ;" * and on 

 inspecting it you will immediately understand that it would be 

 easy for the farmer to establish a system of scientific bookkeeping, 

 by entering on the debtor side the materials that had been ab- 

 stracted from the soil by his crops, and on the creditor side that 

 restored to it by his manure : thus enabling him to ascertain 

 whether his plan of farming has a tendency to enrich or to im- 

 poverish his land. From this table it will appear that if an 

 average crop of — 



Wheat be reckoned at 30 bushels, weighing 18001b 



will have abstracted from the soil 

 Barley, 36 bushels = 1 ,900 lbs. 

 Oats,' 30 do. 1,200 



Potatoes, 6 tons 13,000 



Turnips, 30 do. 33,000 



C'--'{2::dX'"'"Td"'l= 2i at 1 ton per load 



Beans, 24 bushels, ' 1,200 lbs. 



Let us next illustrate this method of bookkeeping by reference 

 to the Table now in the room, in which I have quoted the results 

 given by Mr. Morton in his interesting work on soils, with re- 

 spect to the system of husbandry pursued by him on Lord Ducie's 

 example-farm at Tortworth. It will there be seen that, adopting 

 his statements, there would have been abstracted per acre from 

 the soil in six years — 



* See Table II., on the Constituents ofcertam crops, a title which I have 

 adopted in preference to that given in the text, as the proportions of the 

 ingredients are by no means cojistant, varying, within certain limits not yet 

 defined, according to circumstances. 

 , VOL. HI. ^ L 



