AGRICULTURAL CHEMISTRY AND GEOLOGY. 



181 



stood that the cost includes rates, taxes, interest, scarifying, reaping in short, all the opera- 

 tions from digging to harvest. 



The parish in which Mr. Smith resides contains two hundred wheat-growing acres ; he 

 calculates that fifty laborers would have dug these in two months and eight days, so that, 

 beginning the last week in September, all would be finished by the first week in December, 

 leaving five months for the occurrence of casualties and their reparation before the crop has 

 grown. His system, after the first plowing, it will be seen, is based entirely on spade- 

 husbandry; he is of opinion, that it is applicable to thousands of acres "of hitherto imprac- 

 ticable and unremunerating clay." 



Schleiden and Smith agree in their faith in nature's unassisted fertilizing powers, if not in 

 their mode of clearing the way for the exercise of those powers. The system of the latter 

 combines fatlow without loss, for the yield is double ; nature is left to drop the ammonia, and 

 the time is given for its combination with mineral matters in the soil. The atmosphere con- 

 tains all the organic elements of wheat, and if the ground be kept stirred, uncrusted, and 

 loosened to a suitable depth, they will find their way in ; and nitrogen even, as late experi- 

 ments demonstrate, will be absorbed. As for inorganic constituents, Mr. Smith believes that 

 they always exist in sufficient abundance, if sought for by frequent digging. 



Capillary Attraction of the Soil. 



FROM numerous observations which have been made at different times on the peculiar ap- 

 pearance of the surface >t - . .luring the warm summer months, and the fact 

 that they, when covered with boards, stones, or other materials, so as to prevent them from 

 supporting vegetation, become, in a comparatively short time, much more productive than 

 the adjacent uncovered soil, led to the belief that the soil possessed some power within 

 itself, aside from the roots of plants, of elevating soluble materials from deep sources to the 

 surface. 



To throw some light upon the subject, in May, 1852, I sunk three boxes into the soil 

 one, forty inches deep ; another, twenty-eight inches deep ; and a third, fourteen inches deep. 

 All three of the boxes were sixteen inches square. I then placed in the bottom of each box 

 three pounds of sulphate of magnesia. The soil to be placed in the boxes above the sul- 

 phate of magnesia, was then thoroughly mixed, so as to be uniform throughout; the boxes 

 were then filled with it. This was done on the li-"ith <>f May, 1852. After the boxes were 

 filled, a sample of soil was taken from each box, and the percentage of magnesia which it 

 contained accurately determined. On the 28th of June, another sample of surface soil was 

 taken from each box, and the percentage of magnesia carefully obtained as before. The re- 

 sult in each case pointed out clearly a marked increase of magnesia. 



On the 17th of July, a sample of the surface soil was taken for a third time from each box, 

 and carefully examined for the magnesia. Its percentage was found to be very perceptibly 

 greater than on the 28th of the preceding month. On the loth of the months of August and 

 September following, similar examinations severally were made, with the same evident gra- 

 dual increase of the magnesia in the surface soil. 



The following are the results as obtained : 



Before the middle of October, when it was intended to make another observation, the fall 

 rains and frosts had commenced ; on this account the observations were discontinued. The 

 elevation of the magnesia, as shown in the above experiments, depends upon capillary attrac- 



