essay because it not only outlines clearly the old, slow process 

 common wherever leather was tanned, but also, in feeling, it 

 conveys the retarded technical state of the leather industry in a 

 country whose textile mills and foundries were the envv of the 

 world. In presenting his findings to the Royal Society in 1778 

 Macbride wrote r"*^ 



The tanners prepare their bark by gently drying it on a kiln, and grinding 

 it into a very coarse powder. They then either use it in the way of infusion, 

 which is called ooze, or they strew the dry powder between the layers of 

 hides and skins, when these are laid away in the tan-pits. 



The ooze is made of macerating the bark in common water, in a particular 

 set of holes or pits, which, to distinguish them from the other hole in the tan- 

 yard, are termed letches. 



The first operation of the tanner is to cleanse his hides from all extraneous 

 filth and remove any remains of flesh or fat which may have been left behind 

 by the butcher. 



The hair is next to be taken off, and this is accomplished, either by steeping 

 the hides for a short time in a mixture of lime and water, which is termed 

 liming; or by rolling them up close, and piling them in heaps, where they 

 quickly begin to heat and putrify. The hair being loosened, is scraped off, 

 and the tanner proceeds to the operation called fleshing which consists in a 

 further scraping with a particular kind of knife contrived for the purpose 



The raw leather is then put into an alcaline ley [bate], in order to discharge 

 the oil, and render its pores more capable of imbibing the ooze. The tanners 

 of this country generally make their ley of pigeon's dung ... or potash. 



The oil being sufficiently discharged, the leather is ready for the ooze, and 

 at first, is thrown into smaller holes, which are termed handlers; because 

 the hides and skins, during this part of the process, are taken up, from time 

 to time, and allowed to drain; they continue to work the leather in these 

 handlers, every now and then stirring it up with a utensil called a plunger, 

 which is nothing more than a pole with a knob at the end of it, until they 

 think proper to lay it away in the vatts. In these holes, which are the largest 

 in the tanyard, the leather is spread out smooth, whereas they toss into the 

 handlers at random, and between each layer of leather they sprinkle on some 

 powdered bark, until the pit is filled by the leather and bark thus laid in 

 stratum super stratum: ooze is then poured on, to fill up the interstices; and 

 the whole crowned with a sprinkling of bark, which the tanners call a heading. 



In this manner the leather is allowed to macerate, until the tanner sees 

 that it is completely penetrated by the ooze: when this is accomplished 

 (which he knows by cutting out a bit of the thickest part of the hide) the 

 manufacture is finished, so far as relates to tanning, since nothing now 

 remains but to dry the goods thoroughly, by hanging them up in airy lofts 

 built for that purpose. Such in general is the process for tanning calf skins 

 and those of lighter sorts of hides which are called butts; but the large, 



'"'Macbride, "Instructions to Tanners," Philosophical Transactions of the Royal Society (1778), 

 vol. 68. The paper was delivered by Sir John Pringle in 1778, and the essay appeared subsequently 



in the Repertory of Arts and Manufactures (1795), vol. 2, pp. 341-354, 382-388. 



24 



