It is this lime-water which is now to be used in making your ooze, instead of 

 plain common water; and this is all the difference between the old and the new 

 method of tanning. . . . Every thing that relates to the cleaning, liming, 

 fleshing, &:c. is to be conducted precisely as in the old or common method 

 of tanning; and the goods are to be worked in the handlers for the requisite 

 time, and then laid away in the vatts, with layers and headings of bark, just 

 as you now practice. 



For sole leather, Macbride recommended altering the process of 

 steeping or raising which swelled the pores of the hide. Previously 

 this had been done by immersion in sour liquors of rye or other 

 grain or milk of lime. To improve the steeping process, Macbride 

 suggested that tanners "imitate the bleachers of linen who make 

 use of a sour prepared by diluting the strong spirit of vitriol 

 (H2SO4) . . . with a sufficient quantity of plain water" in the 

 strength of one wine pint of acid to fifty gallons of water. '^" The 

 hides remained in the sour until sufficiently raised, and then were 

 put "directly into the ooze." Tanning continued as usual after 

 this step, which hastened penetration of the hide by the ooze. 

 Macbride wrote further of his new method: 



Though it is possible to tan small parcels of leather . . . by the use of lime- 

 water ooze, in a fourth part of the time which is required, if only common 

 ooze be made use of; yet the business of a large tan-yard cannot be carried 

 on with so much expedition; but even in large works, and in the common 

 course of business, sole-leather can be completely tanned and finished, in, 

 from eleven to fifteen months, according to the different weights and thick- 

 ness of the hides. Butts in, from eight to twelve months and calf-skins in 

 from six to twelve weeks; in general, the tanner may save at least one third 

 of the time that has hitherto been required.^' 



A contribution equally as significant as Macbride's was made 

 in 1794 by Armand Seguin who succeeded not only in speeding but 

 also explaining "the combination of tannin with the gelatin and 

 fibrine of skins." He speeded the tanning process by placing the 

 hides in tannin of "a liquid and concentrated form." Seguin, the 

 friend and colleague of Lavoisier, made "known the distinction 

 between gallic acid and tannin, and the property which the latter 

 possesses of combining with various animal substances, especially 

 gelatins, forming with it the unalterable basis of leather."'"^" 



Seguin's method of proceeding was described in detail by 

 Julia de Fontenelle and Malepeyre in their volume on The Arts of 

 Tanning, Currying and Leather Dressing. Campbell Morfit edited 



50 Ibid., pp. 125, 126. 

 " Ibid., pp. 127, 128. 

 *2 Morfit, pp. 211, 243. See also McKie, Jtitoine Lavoisier (New York, 1952), p. 146. 



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