140 DR. N. H. J. MILLER ON THE AMOUNTS OF [May I903, 



since, without entirely accepting the opinion that insoluble humus 

 possesses no manurial value, there is no doubt that the much more 

 stable products — hydrocarbons, etc. — obtained from humus and from 

 vegetable matter generally, under the combined influence of heat 

 and steam, are quite useless to crops. 



Prom this point of view, it seems very desirable that the organic 

 matter present in the deposits which form the basis of many soils 

 should receive far more attention than has hitherto been given to 

 them ; and the chief object in recording these results, few and in- 

 complete as they are, is to call attention to a line of investigation 

 which possesses both geological and economic interest. 



Discussion. 



The President referred to the results worked out by the Author 

 as affording another illustration of the bearing of geological facts 

 and phenomena upon agriculture. Pew analyses of rock-formations 

 from deep borings had yet been published, and it was desirable, 

 both from the geological and the economic points of view, that such 

 analyses should be multiplied, and compared with analyses of the 

 same material when occurring at or near the surface, both before 

 and after it had supported vegetation. 



Prof. H. E. Armstrong said that he feared he could add little to 

 the paper, which dealt with a very difficult and intricate question. 

 He would like to know what the Author implied by his distinction 

 between humous and bituminous constituents. Carbon and nitrogen, 

 where present, must have an organic origin. Perhaps the Author 

 intended to distinguish as between the presence of those elements 

 in a form available for the nutrition of plants, and their presence in 

 a form not thus available. Hitherto it had been the practice to 

 look upon the subsoil as agriculturally of small importance, but the 

 speaker suggested that it was desirable to make experiments in 

 which the top soil would be got rid of altogether. We ought to 

 be informed as to the amounts of potash and phosphoric acid : the 

 organic constituents, as they stood, were of small value. The 

 paper was a valuable beginning, but it did not carry one very far 

 towards the solution of the problem which it attacked. 



Mr. Whitaker considered that the Author deserved thanks for 

 giving the results of his work, so far as they went, without waiting 

 for several years till he had completed it. One or two specimens of 

 London Clay were not a sufficient criterion, as its constitution 

 differed widely in various localities, and the same would hold in 

 other cases. He pointed out that the subsoil was made use of 

 in former times, instancing the practice of ' marling ' with Boulder- 

 Clay and with Chalk. It should be borne in mind that the Author's 

 results applied to clays from deep borings, where the influence of 

 atmospheric agencies was unfelt. 



Mr. Hudleston said that, as a ' distressed agriculturist ' farming 

 600 acres of land, he was anxious to learn how the fertility of the 

 soil might be increased, but he had not gathered much in that 



