THE UTILIZATION OF LEATHER WASTE. 
| 
afterwards dried and powdered. A more drastic method is described 
by Feldmann in a French specification, and is applicable to old boots 
and the like. These are treated with steam under pressure until 
reduced to a paste. This is mixed with lime and dried to a powder, 
containing 9 per cent. of nitrogen. 
Very often the leather is mixed with other manurial substance to 
form what is termed a “mixed” manure. One idea on these lines has 
been patented by Leblanc. The leather is dissolved in H,SO, of a 
gravity of 1.563 by heating under pressure. This pasty mass is mixed 
with mineral phosphate and dried. Such a method as this has two 
objects: the leather is rendered soluble, and, in addition, the mineral 
phosphate is also made more suitable for use as a manure. Finally, by 
a process of destructive distillation it has been shown by Lamb that 
almost a theoretical yield of ammonia can ‘be obtained, and the residual 
“char,” or carbon, purified and used for decolorising purposes. In 
a paper published in the J.S.C.I. for 1917 on the utilization of con- 
demned army boots, it was shown that, as the result of a number of tests, 
35 per cent. of crude charcoal is obtained, which on purification with 
acid and alkali gives 25 per cent. (on the original leather) of pure 
charcoal. This product compared well with bone char as regards 
decolorizing power. : ; 
Before concluding, mention should have been made of the property 
possessed by Rochelle salt of dechroming chrome-tanned leather, first 
pointed out by Procter and Wilson. In a paper published on the 
subject it was proved that this salt would completely dechrome, and 
from the residue could be made a satisfactory glue. At the same time 
the chrome could also be recovered from the solution. Rochelle salt 
is a dear chemical, but, as pointed out by the authors, can be completely 
recovered and used again. ee 
The British Department of Scientific and Industrial Research has 
approved of the formation of a Research Association for the silk 
industry. The Secretary of the Association is Mr. A. B. Ball, The Silk 
_ Association of Great Britain and Ireland, Kingsway House, Kingsway, 
London, W.C. 2. 
Construction work for the Tokyo Scientific Laboratory, started some 
time ago under the auspices of the Science Association at an estimated 
cost of £300,000, is making speedy progress, and the latest news is that 
already the Physical Department.has been completed. ~ With the 
completion of this construction, the country will have one of the most 
perfect scientific laboratories in the Orient. . 
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