that if public business had not drawn away the attention of Seguin from his 

 investigations, he might have succeeded in effecting a complete revolution 

 in the art of tanning. As it is, he has numerous followers, many of whom, 

 in England and elsewhere, have patented and used variations of his process; 

 but the essential objection to this mode of operating still attaches to all of 

 them, namely, that the combination of tannin with the gelatine and fibrine 

 upon the surfaces of the skins, takes place so rapidly, that the superficial 

 layer of leather thus formed prevents the passage ot the liquor into the 

 interior of the hide, and consequently its perfect tanning. 



By Seguin's method the hide was first washed and thoroughly 

 cleaned, then the hair was removed by means of lime. x*\fter clean- 

 ing, calf and other light skins were put directly in tan vats contain- 

 ing a solution of bark, water, and one five-hundredths part of 

 sulphuric acid. Where others had stratified their vats with 

 alternate layers of bark and hides, Seguin employed an immersion 

 technique. By having a series of connecting receptacles, the acid 

 tan juice was recirculated through an entire range of vats. If, 

 in the case of sole leather, raising or swelling was deemed necessary, 

 Seguin, as had Macbride, recommended baths of sulphuric acid 

 and water. This removed the hair in 48 hours where previously 

 months had been required. For the lighter variety of hides, 

 raising usually was not required. By his process Seguin could 

 produce finished leather in three or four days.'"^ At a time when 

 French armies were in dire need of leather for shoes, boots, and 

 saddles, this accelerated technique won Seguin the praises of his 

 government.''* But in the speed of the reaction quality was sacri- 

 ficed, because only a superficial layer of leather was formed during 

 the short time that the hides were in the tan vats. 



Sir Humphry Davy, in a series of lectures begun in 1802 on the 

 "Chemistry of the Arts,"^'^ not only defined chemically the transi- 

 tion of raw hide to leather, but also revealed the cardinal principle 

 in the economics of tanning: to make a profit, tanners had to give 

 hides the greatest possible weight in the shortest possible time."'' 

 Davy viewed tanning as an extremely simple chemical process 

 "of great importance to society" with the proper procedures already 

 (1802) reduced to scientific principles; but, alas, "the improvements, 

 resulting from new investigations have not been uniformly adopted 

 by manufacturers." This was not because of miscalculation or 



53 Morfit, pp. 243-248. 



^* McCloy, French Inventions of the Eighteenth Century, pp. 82, 82 (fn. 33). 

 55 Collected Works of Sir Humphry Davy, edit. John Davy, vol. 2, pp. 416-420. 

 5'' Clow, The Chemical Industries, p. 496. 



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