view of determining the causes of the decay of bindings. The Sub-Committee find that this is caused by both mechanical and by chemical influences. Of the latter some are due to the mistakes of the leather manufacturer and the bookbinder, others to the want of ventilation, and to improper heating and lighting of libraries. In some cases inferior leathers are finished (by methods in themselves injurious) so as to imitate the better class leathers, and of course, where these are used, durability cannot be expected. But in the main, the injury for which the manufacturer and the bookbinder are responsible must be attributed rather to ignorance of the effect of the means employed to give the leather the outward qualities required for binding, than to the intentional production of an inferior article....
“We are of opinion that no special skin can be condemned in its original condition, although goat, seal, pig, and calf are probably superior in strength of texture to sheep. Sheepskins are, however, equally resistant to chemical agencies, and being naturally soft and flexible, are extremely suitable for use for purposes where they are not much exposed to mechanical wear.
“Fresh market skins, dry skins, or wet salted skins are much to be preferred to those known as ‘drysalted,’ since the crystallization of the salt which takes place in the drysalting process, tends to weaken the structural fibre of the pelt. No tainted or putrefied skins, even if only slightly affected, are suitable for the manufacture of bookbinding leather, both for the same reason, and because the weakness of grain so produced leads to uneven dyeing.
“In the soaking of skins we would strongly condemn the use of old putrid soaks, or the addition of salt to the soaks to assist in the softening, as both methods weaken the skin. ... Violent mechanical treatment such as ‘stocking’ is injurious....
“The liming should be done in mellow, weak limes. Old limes smelling strongly of ammonia, and containing large quantities of bacteriological products, must be avoided....
“Special care should be taken with regard to the beamhouse work after unhairing and fleshing, as, by excessive or unsound puering and drenching of the skins, their whole
natural strength is frequently destroyed.... Great damage is frequently caused by the use of foul puers or foul bates, in which putrefaction has taken place.
“Pure sumach is the tannage we would most strongly recommend for high class bookbinding....
“The tannage of bookbinding leathers must be a mellow one, and must not be carried too far, as we have found in many cases the cause of decay in tanned leather has been the fact that the leather was overloaded with tannin. Tanning has throughout a hardening effect on the leather fibre, which, if pushed too far, ends in brittleness and loss of tenacity....