348 THE POPULAR SCIENCE MONTHLY. 



stated that these laws were passed in consideration " of the dam- 

 age or injury which many sustained by the ill-curing of leather, 

 and by the shoemakers in making it up into shoes and boots." 

 Thus left to shift for itself, the industry steadily though slowly 

 progressed with the country until I860, when new inventions and 

 improvements in processes, and energetic men at the head of it, 

 gave it a decided impetus which has constantly gained in force 

 since. 



As has been said, the fundamental processes of tanning have 

 changed very little since the early days. The hides, as they came 



Fig. 8. Union Splitting Machine. 



to the tanner, were first washed, and then, in order to remove the 

 hair, soaked in vats of water and lime or ashes. After having 

 been thus unhaired, they were put over a beam and scraped until 

 every remnant of flesh had been removed. After another wash- 

 ing they were " laid away " that is, packed in vats in alternate 

 layers of ground hemlock or oak bark. The object of this was to 

 bring about the desired union of the gelatin and tannin. The 

 operation, however, was a slow one, and oftentimes many months 

 were required to complete it. But study, of course, has been 

 since given to the details of these various steps, which has re- 

 sulted in a marked saving of time. In the preliminary process 

 of depilation there are two methods which are now commonly 

 followed by American tanners. The first is known as the " liming," 

 which is used largely in the preparation of upper leather ; and the 

 second, known as "sweating," which is used for sole leather. In 

 the " liming " process the hides are soaked in a solution of lime 

 and water, as indicated above, until the hair-bulbs are loosened. 

 In sweating there are two methods also : the warm sweat, with 

 the temperature of the pit at 100 ; and the cold sweat, with it at 

 50 or 60. The former method is in general use in southern 

 Europe, while the latter is not only American in origin, but is the 



