14 OF THE ASSIMILATION OF CARBON. 



to 2^ per cent, cellular tissue. Sugar contains 42'4 

 per cent. ; cellular tissue, 47 per cent, of carbon. 



20,000 Ibs. of beet-root, therefore, if they con- 

 tained 9 per cent, of sugar, and 2 per cent, of 

 cellular tissue, would yield 936 Ibs. Hessian of 

 carbon, of which 756 Ibs. Hessian would be due 

 to the sugar, and 180 Ibs. Hessian to the cellular 

 tissue ; the carbon of the leaves and small roots 

 not being included in the calculation. 



One hundred parts of straw *, dried in air, con- 

 tain 38 per cent, of carbon; therefore 1780 Ibs. of 

 straw contain 676 Ibs. Hessian of carbon. One 

 hundred parts of corn contain 43 parts of carbon ; 

 800 Ibs. must therefore contain 344 Ibs. Hessian; 

 in all, 1020 Ibs. Hessian of carbon. 



40,000 square feet of wood and meadow land 

 produce, consequently, 1007 Ibs. of carbon; while 

 the same extent of arable land yields in beet-root, 

 without leaves, 936 Ibs. ; or in corn, 1020 Ibs. 



It must be concluded from these incontestable 

 facts, that equal surfaces of cultivated land of an 

 average fertility produce equal quantities of car- 

 bon ; yet, how unlike have been the different 

 conditions of the growth of the plants from which 

 this has been deduced ! 



Let us now inquire whence the grass in a meadow, 



* Straw analysed in the same manner, and dried at 100 C., gave 

 46-37 p. c. of carbon, 5'G8 p. c. of hydrogen, 43*93 p. c. of oxygen, and 

 4-02 p. c. of ashes. Straw dried in the air at 100 C. lost 18 p. c. of 

 water. Dr. Will. 



