thick, heavy hides, of which the strongest and most durable kind of soal- 

 leather is made, require to have their pores more thoroughly opened before 

 the ooze can sufficiently penetrate them. For this purpose, . . . they 

 are thrown into a sour liquor, generally brewed from rye, in order that 

 the effervesence which necessarily ensues may open the pores. 



The tanners term this operation raising, as the leather is considerably 

 swelled, in consequence of the conflict between the acid and alcali. This 

 is an English invention; for it appears from M. de la Lande, who was em- 

 ployed by the Royal Academy of Sciences to write on the art of tanning, 

 that the foreign tanners know nothing of this branch of the business: indeed, 

 their whole process, according to his account, is slovenly, and even more 

 tedious than our common method, and must make but very indifferent 

 leather. 



When the raising is accomplished, the leather is put into the handlers, 

 and worked in them for the requisite time; then laid away in the vatts, 

 and there left to macerate until the tanning is found to be completely fin- 

 ished which, for the heaviest kind of leather, such as this of which I am 

 now speaking, requires from first to last full two years. At least, the tanners 

 of this country cannot make soal-leather in less time; what they are able to 

 perform in England, I am not so thoroughly acquainted with. 



It is this tediousness of the process which enhances the value ot leather; 

 and the returns being so slow, the trade of tanning never can be carried on 

 to advantage, but by persons possessed of a large capital; therefore, one 

 sure way of increasing the number of tanners, and of course of bringing 

 down the price of their manufacture, is to shorten the process; and if at 

 the same time we can improve the quality of the leather, and save some- 

 what in the expence of tanning materials, the public will be essentially 

 benefited in respect to one of the necessary articles of life. 



All this, I will venture to say, can be done by pursuing the method which 

 is laid down in the inclosed paper, and which may be introduced into any 

 common tanyard. 



With respect to time it is possible, in the way that I have found out, to 

 finish leather in a fourth part of what is required in the ordinary process; 

 for I have repeatedly had calf-skins tanned in a fortnight or four weeks, 

 which in the common way would not be done in less than from two to four 

 months. 



I shall not pretend, however, to affirm, that that business can be carried 

 on in the large way with such expedition; because a great deal of this abridg- 

 ment of time was probably owing to frequent handling and working of the 

 leather; but I am confident, and know it from four years experience, that in 

 the ordinary course of business, and in a common tan-yard, the tanner may 

 have at least four months out of twelve, produce better leather, and find 

 his bark go much farther than in the old way of tanning. 



What was Macbride's new process? For butts and calt skins it 

 was simply "that Hme-water extracts the virtues of oaiv bark 

 more completely than plain water." ^^ 



« Macbride, vol. 68, p. 120. 



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