286 Notices of the Labours of Continental Chemists. 



heated the white vapours disappear, the products are no 

 longer combustible, and the recipient contains an acid colour- 

 less fluid abounding in aceton. When white vapours are 

 no longer visible, oily stripes are formed in the neck of the 

 retort, indicating the formation of a new product. If the 

 yellow residue be dissolved in water it forms no crystals even 

 at O^ cent., when evaporated to the formation of a pellicle, 

 and the cokl and solidified mass then treated with aether, but 

 little citric acid remains undissolved. The aether on evapora- 

 tion leaves behind a warty granular mass — the aconitic acid. 

 Since citric acid does not form an sether on treating its alco- 

 holic solution with hydrochloric gas, the aconitic acid may 

 be thoroughly purified by dissolving it in five parts of abso- 

 lute alcohol, and passing hydrochloric gas through the solu- 

 tion. The aconitic Eether is then decomposed with a vinous 

 solution of potash, the potash salt by acetate of lead, and the 

 washed precipitate decomposed with sulphuretted hydrogen ; 

 it is then obtained as a laminar crystalline acid, which on re- 

 solution in aether and slow evaporation appears colourless 

 and verrucous-crystalline : it consists of C ^I'S*, H 3*4-l, 

 O 54-75. The silver salt was employed to determine the 

 atomic weight, which was found to be 618*1 1; the formula is, 

 therefore, C^ H- O' + H- O. The silver salt is white, not 

 quite insoluble in water; formula = C* H- O^ Ag O. Aco- 

 nate of barytes is gelatinous, when dried, amorphous. The 

 salts of potash, soda and ammonia, do not crystallize distinctly, 

 are easily soluble in water and in alcohol. Aconitic aether, 

 the preparation of which has already been described, is co- 

 lourless, of aromatic smell and bitter taste ; specific gravity 

 = 1-074 at + 14° C. ; boils at 236°, above which it decomposes 

 almost entirely into white vapours and a black fatty residue. 



Fornuda = C^H>- O* = Ae O At. 



The same aether has likewise been prepared by Dr. Mar- 

 chand in the following manner. A mixture of half a pound of 

 citric acid, three quarters of a pound of alcohol, and a quarter 

 of a pound of concentrated sulphuric acid was distilled in a 

 sand bath for about four hours, the liquid that passed over 

 beino- constandy poured back. At last only sulphuric aether 

 mixed with a little alcohol passed over, and the mass had a 

 very dark brown colour. On mixing with water a quantity 

 of coloured aether separated, which was washed with water 

 till acid reaction ceased. When decolorated by means of 

 animal charcoal, it formed a yellow fluid, very similar to the 

 usual citric aether. Its boiling point above 230°. It could 

 not be distilled without decomposition, so that it was impossi- 

 ble to take the specific gravity of its vapour. Dr. Marchand 



