45 



3. — There appears, however, to be some non-biological slow 

 decomposition also, since the decomposition in unmanured soil 

 poor in micro-organisms is much slower than in manured soils, 

 and altogether different in character. 



Autoclax'ing the soil at 130'' for 20 minutes destroys the cause 

 or causes of the decom)X)sition altogether, but the action proceeds, 

 although mu(^h more slowly, than in untreated soil, in the presence 

 of a considerable amount of toluene and mercuric chloride. 



Partial sterilisation by treatment with toluene which was 

 evaporated before the addition of phenol increases the rate of de- 

 composition, but steaming does not. 



The decomposition takes place even in soil air-dried to 2A% 

 moisture, but it is extremely slow compared with the rate in 

 normal soil. 



When successive doses of phenol are applied to the same soil, 

 each dose is decomposed at a higher rate than the preceding one. 

 This is entirely in ac(X)rdance with a decomposition mainly bio- 

 log-ical in chararMcr. The same effec^t has been observed in the case 

 of ?i/ -ere so I. 



The treatment of the soil with sulphuric acid (50% by volume) 

 either before or after the addition of phenol greatly augments the 

 instantaneous loss, which may amount to 90";^ in case of phenol 

 This loss is not affected bv autoclnving. 



CONDITIONS DETf'RMININCi ENVIRONMENTAL 

 I ACTORS IN THE SOIL. 



NX HI. B. A. Kkhx. "A Note on the Capillary Rise of 

 ll'atci' in Soils. " journal of Agriculturnl Scien<T, 

 1919. Vol. IX. pp. 396-399. 



A simple formula for the theoretical maximum rise in an- ideal 

 soil, composed of closely packed and uniform spherical grains, 

 may be obtained from a ( onsideration of the triangular pores 



existing in such a soil. The formula reduces to h=^ where 



r 

 h^^^ height of rise and r radius of spherical grain. The capillary 

 rises gi\en in the following table are calculated on the assumption 

 that a soil is made up entirely of one given soil fraction, and not of 

 a mixture of fractions, and the particles are t;iken as closely 

 packed spheres : — 



