Intelligence and Miscellaneous Articles, 231 



consigned, made an interesting observation : having immersed a 

 piece of litmus paper into the crucible to try whether the vapour 

 was acid, he observed that the part immersed retained its colour, 

 whilst that which was even with the orifice of the crucible became 

 evidently red. The temperature was therefore higher in this place, 

 and it is to be presumed that slow combustion took place analogous 

 to that which occurs in the interesting experiments of Dobereiner. 



Anhydrous sulphurous acid presented M. Boutigny with pheno- 

 mena still more remarkable than aether ; he found that when a little 

 of this acid dropped upon a platina capsule heated almost to redness, 

 the drops were strongly agitated, became round, immoveable and 

 opalescent, and seemed even to crystallize. The small spheroid when 

 placed on the hand produced a sensation of cold. 



M. Boutigny was of opinion, that in this case the sulphurous 

 acid suffered so great a diminution of temperature that it solidified. 

 The commissioner rejects this explanation, and is satisfied with ad- 

 mitting, that the acid under these circumstances evaporating more 

 slowly than in the open air, produces nevertheless, by this slow eva- 

 poration, so considerable a degree of cold as to congeal the moist- 

 ure of the surrounding air, and to become hydrated. This explana- 

 tion is apparently confirmed by the fact, that if the small solid 

 globule be rapidly projected into a tube, and it be immediately 

 corked, the globule disappears, but leaving in the place which it 

 occupied a dew, that remains even when the tube is uncorked. 



M. Boutigny is of opinion that the phenomena described may 

 be connected with the explosions in steam-boilers, and he is still 

 occupied with the subject, and has made a great number of experi- 

 ments with different liquids, and particularly with alcohol of dif- 

 ferent degrees of strength, with aether, oil of turpentine and lemons, 

 and with alkaline and acid solutions. — Journal de Pharm., Mai, 

 1840. 



HYDROMELLONIC ACID. 



Discovered by L. Gmelin. Prepared by dissolving mellonuret of 

 potassium in boiling water, and adding to the solution hydrochloric, 

 sulphuric, or nitric acid. A dirty white gelatinous precipitate which 

 dries to a yellow powder, the hydrated hydromellonic acid. It is 

 slightly soluble in cold, more freely in hot water, has a slightly acid 

 reaction, and is not decomposed by hydrochloric and nitric acids. 



Formula C 6 N 4 + H; eq. = 94*32. Turner's Elements of Che- 

 nristry, p. 796. 



CHROMIC ACID. 

 M. J. Fritzche prepares chromic acid by the careful addition of 

 concentrated sulphuric acid to a hot concentrated solution of bi- 

 chromate of potash ; a crimson bulky precipitate is obtained, which 

 is dried first by heat, and afterwards in vacuo. This is entirely 

 chromic acid, which is to be washed to get rid of the mother water, 

 and of the sulphuric acid which adheres to it. The author could 



