WEARING QUALITIES OF SHOE LEATHERS. 
23 
vestigation. Disregarding the possibility of misfitting, it would seem 
that a full double sole and double shank of heavy lent tier ia respons- 
ible for the wasteful excessive toe wear. A shoe with such a sole bends 
but little and the weight of the body is concentrated at the extreme 
end of the sole, instead of being distributed over a greater area at the 
ball. Even when a double sole is used on the ball of the foot, the 
shank should not be doubled, thus saving leather in making the shoe, 
lengthening its period of service, and reducing the cost of repair. 
Serviceability of various tannages. — The average wear resistance of 
the sole leathers, classified according to the predominating tanning 
material, is practically the same for all three types. The average 
wear per 9 irons is as follows: Oak bark tannages, 78 days; hemlock 
bark tannages, 79 days; and chestnut wood extract tannages, 80 
days. Belting leather shows a slightly higher wear resistance, 
the average wear per 9 irons being 85.5 days. Waxed chrom< - 
tanned leather, with 102 days wear, was next in order, while un- 
waxed chrome-tanned leather, with an average of 126 days wear, was 
best of all. Fiber soles, with an average of 122 days wear, were a good 
second, except for the physical failures already discussed. The 
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4//V WAXED CMtfOA 
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Fig. 2.— Summary of wear data on soles. 
long wear of the unwaxed chrome-tanned leather soles is striking. 
The results (Fig. 2) indicate that such leather may be exceptionally 
serviceable in dry sections of the country. 
Loaded leathers. — Under the conditions of these tests, loading with 
glucose and epsom salts does not materially affect the serviceability 
of leather. It simply adds to the cost. These findings, however, 
might have been quite different had the shoes been worn where the 
climate was wet. 
Rolled leathers. — Approximately 16 per cent greater wear (or the 
rolled than for the unrolled leathers was shown. 
Well-oiled leathers. — The results on leather oiled in various ways 
are not satisfactory, because the differences in oil contents o( the 
lots were not sufficiently great. The indications are that the sole 
leathers of normal oil contents wear about S per cent longer than do 
the well-oiled leathers. This indication needs further confirmation 
before it can be accepted as final. 
