72 Experiments and Observations on the 



by incineration, a considerable portion of carbonate of pot- 

 ash, and a small quantity of carbonate of Inne. 



The fluid remaining after the separation of the precipi- 

 tate was of a dark brown colour, and became green at tlie 

 surrace when it was exposed to the air. It gave no preci- 

 pitate to solution of gelatme, and afforded only an olive- 

 coloured precipitate with the salts of iron, 



W hen muriatic acid was poured into the clear fluid, a 

 violent effervescence wa^ produced ; the fluid became tur- 

 bid ; a precipitate was deposited j and the residual liquor 

 acted upon gelatine and the salts of iron in a nianner si- 

 iriilar to the primitive infusion. 



M. Dcyeux, in di§tillmg the precipitate from infusion 

 of galls by carbonate of potash, obtained crystals of galliq 

 acid. In following his process, I had similar results f and 

 .a fluid came over which reddened litmus paper, and pre- 

 cipitated the salts of iron black, but did not act upon gela- 

 tine. 



When the precipitate by carbonate of pn.tash was acted 

 .upon by warm water, applied in large quantities, a consi- 

 derable portion of it was dissolved; but a part remained 

 which could not in any way be made to enter into solution, 

 and its properties, were vcfv difierent from those of the en- 

 tire precipitate. It was not at all afiected by alcohol : it 

 was acted on by muriatic acid, and partially dissolved ; and 

 the solution precipitated gelatine and tlie salts of iron. It 

 afforded, by incineration, a consid(;rable portion of lime, 

 but no alkali. 



In comparing these facts it \vould seem, that the preci- 

 pitate from infusion of galls consists partly of tannin and 

 gallic acid united to a small quantity of alkali, and partly 

 of these vegetable matters combined with calcareous earth ; 

 and it will appear probable, when the iacts hereafter detailej 

 are examined, that both the potash and the lime are con- 

 tained in these compounds in a state of union w^th carbonii? 

 acid. 



The solutions of carbonate of soda and of carbonate of 

 amtiionk'\, both precipitated the infusion of galls in a man- 

 ner similar to ihe carbonate of potash ; and each of the pre-; 

 cipltafe.?, when acted on by boiling water, left a small quan- 

 tity pt insoluble matter, which seemed to consist chiefly of 

 tannin and carbonate of lime. 



The eiuirc: precipitate by carbonate of soda produced, 

 when incinerated, carbonate of soda and carbonate of liinc. 

 The precipitate by carbonate of ammonia, when exposed to 

 a heat sufficient to boil water, in a retort having a receiver 



attached 



