1882.] COMMERCIAL FERTILIZERS. 81 



pound of the solid matter of the animals which does not pass into 

 trade. Tn New Haven and possibly in other cities in the state, the 

 largest slaughtering establishments have apparatus for converting 

 offal into a fertilizer which will bear transportation and storing 

 for a time. The blood when drawn from the animals flows into a 

 tank where it is cooled. All the albumen is coagulated by cook- 

 ing and sinks to the bottom, and the " soup " is thrown away. 

 The solid residue of the blood, together with all the waste parts of 

 the viscera are then put into a cylinder having a revolving shaft 

 with arms, which are hollow and filled with steam. 



The mass in this way is thoroughly mixed and dried till it 

 contains not far from 1 per cent, of water. 



The odor though unpleasant is not at all powerful, and if the 

 material contains not more than 1 per cent, of water it will keep 

 well. Some farmers the past year have got small lots direct from 

 the driers, and, obtained in this way, it is one of the cheapest 

 sources of supply. 



Another way of preparing the blood is to dry it at a much 

 higher temperature in kilns. The product is black, not red like 

 the st-eam-dried; it is much dryer, and of course richer in nitro- 

 gen. It has no disagreeable smell and will keep without decom- 

 posing indefinitely in a moderately dry place. The market prices 

 of these two kinds of blood are scarcely different, though it 

 would seem as if the quality of the kiln-dried blood as a fertilizer 

 might be somewhat injured if the heat was allowed to become too 

 intense. 



Tankage is another name given to a class of goods which con- 

 tain no blood, but flesh and viscera, together with considerable 

 bone. About the mode of preparation, I have not been able to 

 learn. Some samples appear to contain a good deal of hair or 

 wool which has very little fertihzing value. 



I have no time to do more than briefly call attention to two 

 articles which are being introduced into our retail market as con- 

 stituents of commercial fertilizers, and which are of very inferior 

 value in comparison with those already mentioned. 



One of these is wool dust or shoddy, from the woolen factories, 

 which is rich in nitrogen and convenient to use as a drier with pasty 

 superphosphates. Like hair and horn shavings, it is rich in nitro- 

 gen, and when it can be bought at a reasonable figure and applied 

 in sufficient quantity is a good thing; but it is not a fair thing to 

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