188 [Assembly 



stronger liquor. The excess of tanning in the strong, seizing upon 

 the dissolved gelatine in the weak liquor, will combine with it, and 

 be precipitated in flakes, of a dark curdled appearance, to the bot- 

 tom. At the Prattsville tannery, the greatest strength of liquor used 

 for handling, as indicated by Pike's barkometer, is 16°; of that em- 

 ployed in laying away, the greatest strength varies from 30° to 45°. 



After the leather has been thoroughly tanned and rinsed, or scrub- 

 bed by a brush-machine or broom, it will tend very much to improve 

 its color and pliability to stack it up in piles, and allow it to sweat 

 until it becomes a little slippery from a kind of mucus that collects 

 upon its surface. A little oil added at this stage of the process, or 

 just before rolling, is found to be very useful. 



Great caution is necessary in the admission of air in drying, when 

 first hung up to dry. No more air than is sufficient to keep the sides 

 from moulding should be allowed. Too much air, or, in other words, 

 if dried too rapidly in a current of air, will injure the color, giving 

 a darker Lue, and rendering the leather harsh and brittle. To insure 

 that the thick parts or butts, shall roll smooth and even with the 

 rest of ♦he piece, it is necessary that the leather should be partially 

 dried before wetting down for rolling, and that when wet down, it 

 should lay long enough for every side to become equally damp 

 throughout. 



The following table, condensed from the tanning records of 

 200,000 hides, exhibits the time required to tan the various descrip- 

 tion of hides at my establishment, during a period of four years. It 

 will be seen that the same description of hides require different 

 times in different years. This is owing mainly to a difference in 

 the temperature and weather of the several seasons, and the quantity 

 of sides and strength of liquor in the vats, and partly to the differ- 

 ent conditions and qualities of different lots of the same description 

 of hides: 



No. of Time of 

 sides. tanning. 



Months. Bayi. 



1841— San Juan, 7,500 4 20 



Orinoco, 3,500 5 15 



" 1,900 6 -. 



" 9,000 6 10 



Laguira, 22,000 7 15 



Orinoco, 6,500 5 15 



1 



