Specification of William Edward Newton : preserving skins.

  • William Edward Newton
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: Specification of William Edward Newton : preserving skins. Source: Wellcome Collection.

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    Newtons Improvements in the Treatment and Preservation of Skins. found that if skins be steeped in liquid hydrocarbons previously to being sub¬ mitted to the action of the chemical ingredients used in the ordinary operations of tanning or dressing, the action of the chemical agents on the skins has been much facilitated, and the tanning or dressing operations consequently con- 5 siderably shortened; the quality of the product is also much improved. This result having been obtained, proved the powerful tanning action of this pre¬ serving process, and the advantage attending its employment for the purpose of tanning and dressing skins; this result therefore led to experiments as to whether the various hydrocarbons which are distilled under one hundred and eighty-five 10 degrees centigrade, known in commerce under the name of light oils, and also tar itself, either raw or rectified, might act in the manner of heavy oils in the above-mentioned processes. The results of the experiments fully confirmed what had been supposed ; it was observed, that in whatever manner the hydrocarbons wrere employed, whether heavy oils, light oils, raw or rectified 15 tar, and whether put into the vats together with the tanning liquor, or whether the skins be steeped therein before the unhairing process, or after being scraped and washed, and before being put into the tubs or vats, the action of the hydrocarbon always produced considerable advantages other processes hitherto known, and in which no hydrocarbon was employed. An explanation of the 20 various reactions produced by these hydrocarbons upon the skin itself, and during the process to which it is submitted, will shew that the result with them all must be the same. These hydrocarbons coagulate the albumen (that is to say) curdle the blood, and consequently retain in the pores of the skin a reddish viscous liquid, which is a deperdition of gelatine, of which 25 leather is usually deprived. As the blood which has been retained in the skin is only partially decomposed under the action of the lime in the depilatory operation, the fibrin remains, which during the process becomes tanned like the fibre of the skin, and thus produces an additional yield by increasing the weight, as, in fact, practice has always proved. The hydrocarbons have also 30 the property of combining with the lime and forming an insoluble compound; if, therefore, a skin with the hair on be impregnated therewith when put into the unhairing or depilatory vessel, the lime will only act upon the roots of the hair and not upon the tissue of the skin, which it has the disadvantage of corroding; it follows that the skin will be supple, and as it will when 35 washed contain no more lime, it will when put into the tan pit be tanned more quickly than if it had not been submitted to the action of the hydrocarbons. These matters have also the important property of precipitating the tannin from its solutions, and of combining with it, therefore if a skin be impregnated with the hydrocarbon and immersed in tan liquor, the tanning operation will
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