Guano as compared ivith Manure. 339 



Organic matter remaining in combination with the 



insoluble residue, and determined by ignition, . 04-145 



Whole amount of organic matter foimd in the soil, as 

 extracted by water, acids and alkalies, and also 

 determined by ignition from the final residue, . 11-373 



Whole amount of organic matter determined in an- 

 other equal portion of the same soil by ignition, . 10-970 



Difference, 00-403 



Insoluble silicates and earthy residue, . . . 78-842 



One hundred parts of the insoluble residue gave by 

 washing and separation, 45 parts siliceous sand, 

 and 55 clayey matter. 



Total per centage, of the whole analysis, . , 98 -2844 



Another soil examined was from the " Ree Ree Bottom," 

 a tract of land occasionally overflowed by the Scioto River. 

 It has been cultivated fifty-one years ; forty-five crops of 

 corn and two or three of wheat have been taken off from it ; 

 it has also been a few years in grass or clover. It has scarce- 

 ly diminished fertility, and now with the most ordinary cul- 

 ture yields on an average, one year with another, eighty 

 bushels of corn to the acre. 



The analysis of this soil gave : — 

 Water, hygroscopic and combined, . . 3-500 



Resinous and waxy matters extracted by alco- 

 hol and ether, ..... -036 



Constituents soluble in pure water : — 



Extract of earth, alkaline chlorids, &c. . '032 



Organic matter — crenic acid, j . . -010 



Iron, lime and silica, . . . . -012 



Total water extract, .... -054 



Total per centage of the same, . . 0-190 



Constituents soluble in dilute acid : — 



Iron, alumina and manganese, . - . 2-760 



Organic matter combined with the above, 0-860 



Silica, 0-560 



Lime 0.390 



