74 



THE SPIRIT OF THE SOIL 



In each case the precipitate first formed from the 

 brown liquid was found to be Humic acid, and it was 

 not unless the reaction was continued that Humin 

 made its appearance. The experiment seemed to 

 suggest that Humic acid might be an intermediate 

 product between Carbohydrate and Humin. On 

 testing the hypothesis it was found that on boiling 

 the Humic acid from Laevulose with a 7*5 per cent, 

 solution of Hydrochloric acid for four hours, 98 per 

 cent, of it became Humin, while on treating Humic 

 acid derived from peat in the same way 3*5 per cent, 

 of it became Humin. 



The result, while confirming the possibility of 

 Humic acid being a transition stage between Carbo- 

 hydrate and Humin, was a curious one, and suggested 

 a reason for the great variations between the ana- 

 lytical results obtained by different chemists with 

 peat. Further, while the Humic acid from the 

 sugars and that from peat were almost identical in 

 appearance, solubility and behaviour to alkalis, 

 they showed striking differences in composition. 

 Neglecting decimals, the analyses of the two acids 

 gave * 



The authors responsible for the analysis given in 

 this table concluded that there must be structural 

 * Robertson, Irvine, and Dobson. 



