TANNING. 205 



washed in water, are put into lime pits, as before 

 mentioned, where they are taken up and put down 

 every third or fourth day, for a fortnight or three 

 weeks, in order to destroy the epidermis of the 

 skin. The hair is then scraped off, and the excres- 

 cences being removed, they are put into a pit of 

 water impregnated with pigeon dung, called a 

 grainer, forming an alcaline ley, which in a week 

 or ten days soaking out the lime, grease, and sa- 

 ponaceous matter (during which period they are 

 several times scraped over with a crooked knife, to 

 work out the dirt and filth), softens the skins, and 

 prepares them for the reception of the ooze. They 

 are then put into a pit of weak ooze, in the same 

 manner as the hides, and being frequently handled, 

 are by degrees removed into a stronger, and still 

 stronger liquor, for a month or six weeks, when 

 they are put into a very strong ooze, with fresh 

 bark ground very fine, and at the end of two or 

 three months, according to their substances, are 

 sufficiently tanned : when they are taken out, 

 hung on poles, dried, and are fit for sale. These 

 skins are afterwards dressed and blacked by the 

 curriers, and are used for the upper leathers of 

 shoes, boots, &c. 



The lighter sort of hides, called dressing hides, 

 as well as horse hides, are managed nearly in the 

 same manner as skins ; and are used for coach- 

 work, harness work, &c. &c. 



As the method of tanning above described, and 

 all others in general use, are extremely tedious and 

 expensive in their operation, various schemes at 

 different times have been suggested to shorten the 

 process, and lessen the expense. 



Much hght has been thrown by modern che- 

 mists upon the theory of tanning, and considerable 



