18 REPORT OF THE AGRICULTURAL RESEARCH 



and it is very probable that if artificial manures are ever 

 used in India generally, it will pay to use superphosphate 

 on some of these lands. Of potash there is an abundance, 

 whilst of organic nitrogenous matter there is the same defi- 

 ciency that is so common to Indian soils. Respecting their 

 physical condition they are generally good. 



A question was incidentally raised as to whether the 

 lands under the Lower Swat River Canal had deteriorated 

 at all. So far as one can tell from these samples, 

 and they were taken from widely separated places, there 

 was nothing to indicate that any depreciation has occurred, 

 and in fact generally these were richer and better than 

 those from the other area. 



The Percolation Test for soils. — Some years ago 

 I devised a method for testing the permeability of soils to 

 water. Its immediate object was then the differentiation 

 of certain usar soils of the United Provinces. 



During the past year a long series of tests with it have 

 been applied to good agricultural soils in order to ascer- 

 tain its more general applicability. The test appears to 

 make a sharp differentiation between soils which are 

 physically good or bad respectively. The information 

 which has been gathered on the subject will be submitted 

 for publication shortly. 



V. — Saltpetre. 



The experiments on improvements in the saltpetre 

 refining process advanced a stage this year. A filter press 

 was obtained from Europe which has shown itself able to 

 deal with the mud very expeditiously. The pumps sup- 

 plied with the press were, however, defective and another 

 mode of applying the liquid to the press will now be tried 



In the meantime the solubility relations of the chief 

 salts which are present have been worked out by Babu 

 Jatindra Nath Mukerjee and myself and published as 

 Memoirs of the Department of Agriculture in India. 

 Chemical Series, Vol. Ill, No. 7. 



