on the constituent Parts of astringent Vegetables . 261 
to evaporation ; and, in this process, the infusion of the oak 
bark furnished 17 grains of solid matter; that of the Leicester 
willow about i 6 ± grains; and that of the Spanish chesnut nearly 
an equal quantity. 
The tannin given by these solid matters was, in that from the 
oak bark infusion, 14 grains; in that from the willow bark 
infusion 14^- grains; and in that from the Spanish chesnut bark 
infusion 13 grains. 
The residual substances of the infusions of the Spanish chesnut 
bark, and of the oak bark, slightly reddened litmus-paper, and 
precipitated the solutions of tin of a fawn colour, and those of 
iron black. The residual matter of the infusion of the willow 
bark, did not perceptibly change the colour of litmus ; but it 
precipitated the salts of iron of an olive colour, and rendered 
turbid the solution of nitrate of alumine. 
The solid matters produced by the evaporation of the infu- 
sions, gave, by incineration, only a very small quantity of ashes, 
which could not have been more than yy- of their original 
weights. These ashes chiefly consisted of calcareous earth and 
alkali ; and the quantity was greatest from the infusion of 
chesnut bark. 
The infusions were acted on by the acids, and the pure alkalis, 
in a manner very similar to the infusion of galls. With the so - 
lutions of carbonated alkalis, they gave dense fawn-coloured 
precipitates. They were copiously precipitated by the solutions of 
lime, of strontia, and of barytes; and, by lime-water in excess, 
the infusions of oak and of chesnut bark seemed to be deprived 
of the whole of the vegetable matter they held in solution. 
By being boiled for sometime with alumine, lime, and mag- 
nesia, they became almost colourless, and lost their power of 
