No. 6. DEPARTMENT OF AGRICULTURE. 471 



Since the passage of this Act, no instance of such declaration has 

 in any cavse come to my attention. Furthermore, a careful micro- 

 scopic examination of thousands of samples has failed to show their 

 presence. Yet these low grade materials continue to go by the train- 

 load to the fertilizer factories and doubtless do not stay there, but 

 come out in some condition in the fertilizer output. 



These facts are admitted in a general way by fertilizer manufac- 

 turers. They explain that these raw materials, with the possible ex- 

 ception of peat, are, while employed in the make-up of the fertilizer, 

 not introduced as leather, hair, etc., but are, in the course of manu- 

 facture, changed into other substances whose nitrogen is available; 

 that by such use the general cost of fertilizer nitrogen is held down 

 far below the point to which it would rise if the manufacturer were 

 limited to high-grade sources of supply ; and that the buyer is not 

 injured because he really gets, as the result of the process employed, 

 a highly available fertilizer. 



I have yet to be convinced that the buyer is not somewhat injured 

 because of the price he is asked to pay for this nitrogen in mixed 

 fertilizers, even though the truth be admitted that the manufacturer 

 has been at some expense in its treatment and has, by its general 

 use, somewhat held down the prices of high-grade materials. 



At this time, however, I desire to confine attention to the question 

 whether the process or processes used, do really change the nature 

 of these low-grade materials so as to increase considerably their 

 availability. 



The process is simple and consists either in disolving the hair, 

 leather, garbage tankage, etc., in the sulphuric acid later to be used 

 in dissolving the phosphate rock that forms the major part of the 

 fertilizer; or, in other factories, in putting the ground rock and 

 leather, hair, etc., together into the mixer and then adding the acid. 

 The product is a dark, spongy material called ''base goods," because 

 it is not sold directly as a fertilizer, but forms the base or principal 

 part of various mixtures with high-grade nitrogenous materials, ni- 

 trate of soda, sulphate of ammonia, potash salts, usually with some 

 ground limestone to act as a dryer or neutralizer of the excess acid, 

 and sometimes with raw, ground peat to serve as a conditioner; 

 that is, as an improver of the drilling quality of the mixture, when- 

 ever that seems advantageous. 



To determine whether such treatment fully destroys the hair, 

 leather, etc., upon which it acts, and whether the products are really 

 much more available to plant, I have made a careful study of the 

 effects of the treatment upon a large number of substances, with 

 the aid of my assistants in the Dei>artinent of Experimental Agri- 

 cultural Chemistry of the Experiment Station. The full description 

 of the experiment and of its results will appear in the forthcoming 

 report of the Station, but I have considered the question dealt with 

 of such present imj^oitance as to warrant my placing before you at 

 this time the conclusicms thus far reached. 



The list of materials studied included sole leather scrap, soft 

 leather frf)in glove factories, ])ulverized steamed leather, cleaned 

 cattle hnir sue)) as ])lasterers use. rotted hair, impure wool waste, 

 fine horn meal, impure hoof scrap, peat meal and garbage tankage, 

 together with a sample of ''base goods" from a large fertilizer fac- 



