346 



an abstract, and without such the discussion that succeeds would not 

 be sufficiently intelligible to be useful. It may be interesting to 

 state that measurements have shown that the average mass of soil 

 interpenetrated by the roots of each cotton plant in Alabama is 

 about 5 cubic feet ; within this bulk of soil a sufficient amount of 

 inorganic constituents for the plant must be found naturally, or be 

 artificially transferred to it. 



Professor Mallet compares his results with the analyses of Indian 

 soils made by Dr. Forbes Watson, pointing out both similarities and 

 differences. 



In concluding his analyses of the soils and subsoils, the author 

 gives also one of the so-called " Rotten Limestone," and of the 

 " Bored Rock," both calcareous rocks of a very friable character that 

 underlie the Cane Brake soils. He concludes his elaborate research 

 with some general deductions from his examination of Alabama cotton 

 soils, and with an appendix, in which he describes the mechanical or 

 agricultural methods employed in that State in the treatment of the 

 same. These are given as follows in the words of the paper. 



General Deductions from the examination of Alabama Cotton-soil. 



In order to draw any useful conclusions from experiments such as 

 the above, upon a soil, the plant to be cultivated must be noticed, as 

 well as some of the modes in which it is affected by climate. 



A few remarks upon the cotton plant and its climatal peculiarities 

 must therefore be made here in anticipation of a future part of the 

 paper. 



Annual cotton, as cultivated in America, is a plant which attains 

 its principal growth in about four months, although it continues to 

 develope seed and fibre for a much longer period. 



The extent to which its roots penetrate the soil has been noticed 

 above, and from this some imperfect idea may be formed of the power 

 which it possesses of drawing upon the earth for nourishment, although 

 no measure is thereby obtained, I think, of the capacity of the earth 

 to yield nourishment*, as is shown by the experiments upon capilla- 

 rity and saline absorption. Nor, indeed, do we even obtain any cer- 



* On the assumption of Liebig that mineral food is taken up only by direct 

 contact with the roots the surface exposed by the latter does become a measure 

 of the capacity of any particular soil to yield such nourishment. 



