* * H.

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SPIRIT OF DISCOVERY.

_Tanning_.


The tanner steeps the skin at first in a weak infusion of bark, until it
has acquired a nutmeg brown colour, and then he gradually increases the
strength of the steeping liquors, and after a time he draws the skin
out, and finds that it is converted into leather. A thick piece of hide
requires ten, twelve, or fourteen months, to be converted into good
leather; and when you consider the length of time consumed in the
process, and the great capital necessarily employed, you cannot feel
surprised that various plans should have been proposed to lessen both.
It was proposed to tan with warm instead of cold liquors; and although
the tan appeared to promote the skins in a shorter time, the quality of
the leather was so much injured, that it was soon given up. Then it was
tried to force the tan through the pores of the skin, by employing great
pressure; but this was not found to answer. But you may ask why the
tanner does not put the skins at once into a strong liquor? The reason
is, that the exterior surface of the skin would soon become tanned, and
the central part would remain untanned, which, in a short time, would
begin to rot and decay, and the leather so treated would soon fall to