tke characteristic Properties of Tanni/i. J 3 



a few of them, yet T shall relate some experiments which I 

 have lately made on the peels of walnuts. 



It is well known that when these are kept in small heaps 

 for a short time, they become soft, and .break down into a 

 black mass, which affords a brownish-black liquor. Ou 

 these I therefore made the following experiments : 



1. About one ounce of walnut peels, which were become 

 soft and black, was digested in water. 



A dark brown liquor was thus formed, and, being filtrated, 

 was examined by a solution of isinglass, but not any appa- 

 rent effect was produced. 



2. On an equal quantity of the walnut peels, in the same 

 soft black state, a small portion of nitric acid was poured, 

 and after being digested for about five hours, the whole was 

 evaporated to dryness. The residuum was of a brownish 

 orange colour, and yielded a similar coloured solution to 

 water when digested with it. This was filtrated, and upon 

 the addition of solution of isinglass became turbid, and 

 deposited a tough precipitate, which was aiot dissolved by 

 boiling water. 



3. Another portion of the walnut peels was moderately 

 roasted, and was then digested in water ; the brown solu- 

 tion was filtrated, and formed a slight precipitate with 

 gelatine. 



4. On the residuum of the last experiment, a small quan- 

 tity of" nitric acid was poured, some water was then added, 

 the whole was digested during about five hours, and until it 

 became perfectly dry. 



Water fornied with this a brown liquor, which yielded 

 a very abundant precipitate by the addition of dissolved 

 isinglass. 



Upon these experiments we may remark, that the solution 

 ill the first instance cpntained carbon in a state approaching 

 to (oal, for when treated with nitric acid in the second ex- 

 periment, a portion (although small) was produced of the 

 Bamc tanning substance which is formed from the different 

 kinds of coal by nitric acid. 



The third experiment appears to show, that a small quan- 

 tity 



