WATER-PROOF. 



running water, a fufficient time to extraft all the foluble 

 animal matter or lymph ; it will be eafy to determine when 

 that is done, by putting a piece of the hide into water, and 

 heating the water gradually ; if no fcum is formed upon the 

 furface, it is a proof that no lymph remains. 



2dly, Place the hides (after they have been wafhed and 

 cleaned) in a cauldron, fimilar in conftruclion tothofe in 

 which common fait is made ; fill the cauldron with water, 

 which is to be heated to 167 degrees of Fahrenheit, and no 

 more : after the hides have been one hour expofed to this 

 degree of heat, take them out. . 



3dly, Stretch them upon the horfe, and proceed to take 

 off the hair in the ufual manner. 



4thly, Put them again into the cauldron ( which fhould be 

 fo contrived that it may receive as much water from a cock 

 on one fide as is let out from a cock on the other fide), and 

 fo keep up in this cauldron a conftant current of water, of 

 the heat of 60 degrees. 



5thly, Let the hides remain in this cauldron till the water 

 no longer contains any animal jelly ; which may be eafily 

 known by evaporating a fmall quantity of it. 



6thly, Take the hides out of the water and place them 

 upon the horfe, that the cellular and mufcular membrane 

 may be taken off. 



7thly, Wa(h the hides again in running water, then put 

 them again into the cauldron, or one fimilar to it, which is to 

 be filled with filtered tan-liquor. This liquor is to have the 

 fame degree of heat that the water had in the former opera- 

 tion ; the (kins to remain in it till they are completely tan- 

 ned, taking care to put frefh tan-liquor in the place of that 

 which (hall appear to have loft its energy by the combina- 

 tion of its aftringent principle with the hides ; this may be 

 readily known by dropping in a few drops of a folution 

 of green vitriol. 



The author ftates, that leather made according to this 

 fyftcm would be more free than any other from the animal 

 jelly, which is not combined with the tan, and confequently 

 would be lefs fufceptible of moifture. The fibrous part of 

 the ficin being more ftrongly afted upon by the tan-liquor 

 when heated, would become more firm and more diffi- 

 cult to be penetrated by water ; it would be increafed in 

 ftrength and compaftnefs, without lofing any part of its 

 fupplenefs. 



That excellent Swedilh leather fo fuperior to all other, of 

 which boots, breeches, and great-coats are made, is capable 

 of refilling the moft violent rains. This leather is prepared 

 in Jutland with hot water. 



In the common way the tanner contents himfelf, before 

 he delivers the leather to the (hoe-maker, with beating thofe 

 parts which are foft, or which have a very irregular furface, 

 upon a fmooth log of wood with a mallet. The more care- 

 ful tanners beat all their hides ; and this praftice is general 

 in England. 



Befides the ftrong fole -leather already mentioned, leather 

 of a different kind is ufed in a great variety of arts and ma- 

 nufaftures. It is made of (Icins of cows and oxen, but more 

 generally of calves'-fiiins ; it ferves to make the foles of 

 pumps, or women's (hoes ; for belts, harneffes, covering 

 trunks, &c. or the inner foles of men's (hoe?, ar.d the upper- 

 leathers ; in (hort, any kind of work in which the thickeft 

 and ftrongeft leather is not required. All this fort of leather 

 is curried, becaufe leather as it comes out of the pits is by no 

 means fit for the various ufes for which it is intended : it is 

 rough, of an unequal thicknefs, and unmanageable. Th« 

 objeft of the currier's art is to fupple it, and to give it an 

 nniform compaftnefs and denfity ; this objeft he fulfils by the 

 following operations : 



I ft. He triads the (kins, that is, after having foaked them 

 till they are foftened, he kneads them with his feet, to make 

 the water penetrate every part equally. 



2dly, He works them with the pummel ; this is done by 

 applying to the (Icins a fquare tool made of hard wood, about 

 a foot long and five inches broad ; it is furrowed longitu- 

 dinally, and convex at the bottom and flat at top ; it is fixed 

 to the workman's hand by a leather ftrap fo that it cannot 

 flip. This tool by being worked forcibly along both fides 

 of the (kin, firft upon the fide of the epidermis, and then 

 on that of the flcfh, forms the grain of the leather, and gives 

 it fupplenefs. 



3dly, He then works the flvin with an iron inftrument with 

 a blunt edge ; with this he (crapes very ftrongly thofe parts 

 which are too thick, thofe in which there is left any flelli, or 

 any tan, and thofe in which there are hollows ; driving as it 

 were to prefs the luperfluities of the thick parts into thofe 

 which are too thin, and thus to give to every part of the (l{in 

 an equal thicknefs and an uniform denfity. 



4tlily, He pares the flcin with a paring-knife ; this paring- 

 knife is circular : the workman cuts away thofe thick and 

 projefting parts which the operation juft defcribed was 

 not able to remove ; fo that this lall operation may be 

 confidered as completing the objeft of the preceding 

 one. 



After the four operations above-mentioned, the leather is 

 fupple and fmooth, and of an equal thicknefs and denfity in 

 all its parts : it is now in a ft ate capsble of being em- 

 ployed by the workmen who make ufe of it. But the 

 very operations which give it thefe valuable properties ap- 

 pear to injure its compaftnefs. The leather by being 

 beat, ftretched, and (craped, muft neceffarily become more 

 fpongy, and confequently more permeable to water. To 

 remedy this inconvenience, the currier impregnates it with 

 fat or oil. 



To drefs leather with fat, it muft firil be made perfeftly 

 dry. The pores of the leather are then dilated, by paffing 

 it over a clear ftrong fire, and it is rubbed over with a kind 

 of woollen mop dipped in melted fat, pretty hot. The fat 

 thus applied to each fide of the leather penetrates into its 

 fubftance, lodges within its pores, and adhering there fills 

 them up fo as to preclude the entrance of any moifture ; 

 (hould the leather be wet when the fat is applied, it will 

 remain upon the furface, and not penetrate into the fub- 1 

 ftance. 



The manner of dreffing leather with oil is the reverfe ofl 

 this, and is founded upon tlie property which water poffeffesl 

 of fweUing thofe fupple and elailic capillary tube? into which 

 it infinuates itfelf ; alfo that of its not being mifcible withJ 

 oil, and upon that of its evaporating much more fpeedilj 

 than oil. 



The currier therefore foaks thofe (l<ins in water which he I 

 means to drefs with oil, and while they are yet wet, heJ 

 fpreads over them with a wool m.op any kind of fi(h oil. As 

 the water evaporates, the oil takes its place ; and confequently 

 the more the flcins were fwelled with water, the more tho- 

 roughly they become impregnated with oil. 



M. St. Real found the cow-leather dreffed with fat imfc 

 bibes more water than the calf-(]<in dreffod with oil ; but hd 

 attributes this difference to the manner in which the currier 

 applies the fat. He rubs the leather with a kind of mop,| 

 dipped into melted fat moderately warm, it feems impoffiblfel 

 that, by this manner of applying it, the fat can penetrate! 

 into the interior parts of the leather ; the air contained inf 

 its pores oppofes an invincible obftacle to the penetration ofl 

 it. On the contrary, there is no air in the pores of the wetl 

 leather upon which the oil is applied, and the permanentl 



fluidityj 



