the characteristic Properties of Tamiin, ■■ ,67 



pcration became black, leaving a considerable portion of a 

 blackish substance upon the fiker, which was added to that 

 which had been collected by the tirst filtration. The whole 

 was washed with cold vv\-rer, which passed colourless. 

 Boiling water was then poured upon the filter, by which. 

 a considerable portion was rapidlv dissolved, and a brown- 

 ish-black solution was formed, wliich copiously precipitaied 

 gelatine. 



The residuum on the filler was then dried, and beino- col- 

 Iccted was digested in alcohol, which dissolved the greater 

 part. 



The solution in alcohol was filtrated, but (apparently by 

 the effect of air) a considerable deposit was formed on the 

 filter, which was again dissolved by alcohol. Water ren- 

 dered the solution turbid, and a black light flaky substance, 

 which weighed 41 grains, remained upon the filter. The 

 filtrated liquor was then evaporated, and left a grayish-black 

 substance, which weighed 30 grains. This last substancp 

 was highly inflammable, and when burned emitted a very 

 peculiar ouour, resembling partly that of fat and partly that 

 ofasphaltum. It easily melted, and also immediately dis- 

 solved in cold alcohol, from which, like the resinous sub- 

 stances, it was precipitated by water. ^^ 



The black light flaky residuum, wdiich weighed 4J grains, 

 was found to consist partly of the substance above men- 

 tioned and partly of coal, but the proportion of this last was 

 not ascertained. 



Coagulated albumen and prepared muscular fibre were also 

 sepai-ately exjKised to the action of sulj^huric acid in the 

 manner above described, but did not afford any substance 

 <jy which gelatine could be precipitated, coal being the only 

 product which remained. 



Almost cvQry one of the bodies which have been employed 

 in these experi.inen* , seem to be in some measure different 

 in respect to the progressive effects produced upon them by 

 .sulphvfic acid j and all other circumstances being similar, 

 there appears to be a certain period of the process when the 

 production of the tanning substance has arrived at it-^ maxi- 

 mum, after which, a gradual diminution of it lykes placc^ 



K 2 and 



