CHEMICAL SCIEXCE. 251 



been to turn out the leather with little injury to the gelatine, of which it i3 

 largely composed. But their efforts have generally been fruitless. One of 

 the best improvements, in this direction, was a patent granted for the use of 

 potash in combination with lime and salt. In this process the potash robbed 

 the skin of some of its gelatine, and formed soap. The quality of the leather 

 thus produced, though better than that which the old mode permits, is still de- 

 fective. Mr. Wattles claims to have discovered an improvement. The appli- 

 cation of a special soap bath, while it cleanses out the lime, softens the skin 

 and opens its pores for the reception of the tannin liquor, without in any way 

 impairing the gelatine. The combination of soap with the tannin liquor 

 also has an important effect in mollifying the latter, whereby green hides may 

 be introduced without any danger of becoming hard. Indeed, the soap, by 

 neutralizing undue acidity aud opening the pores, causes the liquor to pene- 

 trate the skin, and unite quickly and thoroughly with the gelatine ; the result 

 being the production of a firm, pliable and superior quality of leather. 



Enos's Improved Process. The following is an extract from the specification 

 of a patent granted toRoswell Enos, July, 1855, for tanning leather. 



No new substances are employed, those which the patentee uses having 

 been long known to tanners ; ho only employs them hi a different manner 

 from that which has been practiced heretofore : 



" The hair is first removed from the hides in any usual manner, and the hides 

 thoroughly cleansed in either pure water or in a solution of salt and water. 

 A batch of fifty sides are then placed in a liquor composed by steeping forty 

 pounds of Sicily sumac, or one hundred and fifty pounds of unground native 

 sumac, in two hundred and fifty gallons of water, and adding twenty-five 

 pounds of salt thereto. The sides remain hi said liquor from twelve to twenty- 

 four hours the length of time depending upon the temperature of the said 

 liquor and the condition of the sides. About blood heat is the best tempera- 

 ture for the aforesaid liquor. After the sides have remained the aforesaid 

 length of time in the salted infusion of sumac, the liquor is strengthened by 

 adding thereto somewhere about two hundred gallons of strong oak or hem- 

 lock liquor, and fifteen pounds of salt, and the sides allowed to remain in 

 this strengthened liquor for the space of from twelve to twenty-four hours. 

 The sides should then be withdrawn, and placed in about the same quantity 

 of a strong cold oak or hemlock liquor, containing twenty pounds of salt in 

 solution, and allowed to remain in it for five or six days. They are then with- 

 drawn and placed in the same quantity and quality of liquor save that it 

 should be of about blood-warm temperature, are allowed to remain therein 

 five or six days, which latter operation should be repeated for six or seven 

 times, when the side will generally be found to be completely tanned. While 

 passing through each stage of this said tanning process the sides should be 

 repeatedly handled, as all tanners are fully aware/' 



This is a description of the process. Practical tanners will perceive that 

 neither acids nor alkalies are used for raising the hides, but that the salt sumac 

 liquor is employed for the preparatory, and the common tan liquor for the 

 finishing process. The inventor, an experienced tanner, says: "The salt 

 sumac liquor enters at once into the pores to the very heart of the sides, and 



