SCIENCE, AND INDUSTRY. 
practically all of the oil and leave nearly pure water behind. Stuffing 
consists in treating the hides with greases, such as a mixture of cod oil 
and tallow, which are often added hot to the dry leather. The object in 
applying oils to leather is to prevent brittleness, to increase strength, and 
to impart other properties desirable for certain types of leather, such 
as waterproofness, &. There is much room for experiment in the, 
making of suitable emulsions. 
DYEING. 
Another important process is the dyeing of leather. A pack of 
skins which has been kept together through every process may emerge» 
from thé colour drum with some skins light in colour and others dark. 
Any one skin will be uniform in colour, but one skin may be much 
darker than another. The writer has found that slight differences in 
the amounts of acid carried by chrome-tanned skins cause them to take ~ 
different amounts of dye from the same bath, but difference in acidity 
of different skins scarcely furnishes the full explanation. 
Universitry Cuemists Suoutp Dryerop Tueroriszs. 
The research work which the industry needs is of two very distinct 
kinds, the one pertaining to the discovery of facts and of reasons for 
certain processes, and the other the correlation of those facts and 
application of them to actual leather manufacture. The former requires 
an extraordinarily broad knowledge, of general chemistry and great 
skill in dealing with specific problems in many different fields of 
chemistry. For example, in studying the mechanism of bating,’ the 
investigator should have a knowledge of both bacteriological and enzyme 
actions; he should be familiar with the action of electrolytes upon 
proteins and with the work of H. R. Proctor, of Leeds, and others upon 
the swelling of proteins in certain solutions by absorption of water, 
and he should be skilled in preparing and staining cross-sections of the 
hide for microscopic examination. 
At the end of his investigation he might be able to say with certainty 
that bating has two and only two important functions: the counteraction 
of the swelling caused by the limes, and the removal of elastin fibres 
from the papillary layer. Such a statement properly substantiated 
would do much to elevate a now uncertain process to a scientific basis. 
In the study of chrome tanning the investigator must have some very. 
refined apparatus, particularly a good hydrogen electrode, and he must 
have a very thorough knowledge of physical chemistry. He might be 
able to settle definitely the molecular mechanism of tanning and show 
exactly what essential réles are played by the salts and acids present. 
For the purpose of solving problems of this kind the university is vastly 
better prepared than the tannery. / 
Onemists Famrrar with Tannery Pracrice Suoutp Appiy 
THEORIES. ‘ 
But when it comes to correlating such facts as the university chemist 
might discover and applying them to actual leather manufacture, a 
tannery is necessary as well as a chemist thoroughly familiar with its 
practical workings, and this of course the university could scarcely be 
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