1 54- Intelligence and Miscellaneous Articles. 



carbon. An experiment performed with this view showed that the 

 water given off by the oxahc acid was acid, and that it contained 

 formic acid. This acid appears at first in but small quantity, be- 

 cause it is mixed with so much water, but it distills more and more 

 concentrated, and towards the end of the operation, when the oxalic 

 acid is dried, it has a very penetrating smell and a sharp taste. 

 According to the proportions found of 6 volumes of carbonic acid 

 for 5 volumes of oxide of carbon, and supposing that it is the de- 

 ficient volume of this gas, which with the assistance of water fornis 

 formic acid, it will appear that for 12 proportions of oxalic acid 

 there is formed one volume of formic acid. 



This theoretical result appeared to me to agree very well with 

 experiment ; but I did not satisfy mj'self of it by a direct mode. 

 The hydrogen was unquestionably supplied to the formic acid by 

 water, and not by the oxalic acid, for the carbonic acid and oxide 

 of carbon ought to have been produced in equal volumes ; added 

 to which, it is a necessary consequence of the well-known nature ot 

 oxalic acid, as shown by the experiments of MM. Dulong and 

 Dobereiner. I may remark, that if the decomposition is not urged 

 too strongly, nearly all the oxalic acid is destroyed ; no sensible 

 quantity being volatilized. 



The observations which I have now made, appear to me to ren- 

 der it imperiously necessary no longer to separate oxalic acid from 

 the other combinations of oxygen and carbon, — carbonic acid and 

 oxide of carbon ; it may be arranged among the acids into which the 

 radical enters in two proportions, and the name proper for it would 

 be hypocarbonic acid, analogically with the hyposulphuric, and hy- 

 posulphurous acids, &c. ; but it may perhaps be better to delay this 

 change of nomenclature.— ^H?i. de Chim. xlvi. p. 218. 



ON GALLIC AND PYROGALLTC ACID. BY M. HENRI BRACONNOT. 



According to Berzelius pure gallic acid can be obtained only by 

 sublimation ; that obtained by infusion, he conceives, alway.s con- 

 tains tannin, while M. Braconnot, on the other hand, considered 

 that procured by infusion quite pure. To determine the question 

 Braconnot prepared some by each mode, and the results of his ex- 

 periments are, that they are distinct acids ; to that prepared by infu- 

 sion he appropriates the name o? gcdlic acid, while the sublimed acid 

 he distinguishes by the term oC pi/rogallic acid. 



Some very white gallic acid, which gave no precipitate with ge- 

 latin, was exposed to a heat insufficient to obtain any sublimate; it 

 dissolved into a brown liquid which crj'stallized on cooling j it con- 

 tained, in fact, much gallic acid, with an additional brown matter 

 that gave an abundant precipitate with gelatin. 



Thirty grammes of gallic acid, previously well dried, were gra- 

 dually heated in a proper apparatus to obtain the sublimed acid ; 

 three grammes and a half were procured ; it was very white, and yet 

 the aqueous solution precipitated gelatin. The residue of this 

 sublimation, redissolved in water, gave a brown liquor, which be- 

 came 



