78 Intelligence and MiscellaTieous Articles. 



compounds of terebic acid. Hitherto he has obtained only the com- 

 pounds which correspond to the monobasic terebates ; they are repre- 

 sented by the general formula C'^ H« 0'(C'"Hn)0 = C"H« O^ HO, 

 (C"'H")0. He has obtained the vinic, amylic and methylic com- 

 pounds, which in their general physical properties much resemble 

 others ; thus at common temperatures they are liquid, oleaginous, 

 slightly soluble in water ; they have a hot, acrid, bitter, but not an 

 acid taste ; the vinic and amylic compounds may be distilled without 

 undergoing decomposition. M. Caillot was able to determine the 

 density of the vapour of the vinic compound : it confirmed the results 

 of the elementary analyses. The methylic compound is altered 

 by distillation. 



These compounds act with bases like acids, but the salts which 

 they produce are not permanent. The terebovinate proper for ana- 

 lysis was obtained with great difficulty ; its formula is C" H^ O^, BaO, 

 C'' H^ O. With the slightest increase of temperature these vinic salts 

 reproduce the alcohol from which they are formed, and generate a 

 bibasic metaterebate, half of the vinic acid being set free. This 

 transformation may be represented by the following equation : 



2(C^^ H* 0\ BaO, C^ H^ O) + 7H0, (C" H'^ O" 2BaO) + C^ H" O^ 

 + (C"H«0«,HO,C^H^O). 



The property which terebic acid possesses of forming vinic acid, 

 seems to indicate that this acid may produce bibasic anhydrous 

 salts, of the formula C^^ H** O" 2M0 .—L' Institut , Novembre 7, 1849. 



PAKATARTARIC ACID. 



M. Kestner states that this acid was produced for some years, or 

 from 1822 to 1824 nearly. At this time the tartrates were saturated 

 with carbonate of lime, and the remainder of the tartrates were pre- 

 cipitated by chloride of calcium ; the tartrate of lime was decomposed 

 by great excess of sulphuric acid, evaporation was effected over the 

 naked fire, and the solutions of tartaric acid were decolorized by a 

 current of chlorine gas ; this operation was performed cold, and it 

 was then remarked, and more -especially in winter, that crystals of 

 parataric acid were formed which were carefully separated, because 

 they rendered the crystallization of the tartaric acid irregular when 

 they remained mixed with it. 



M. Kestner states that since the above-stated period, tartar has 

 been saturated by caustic lime, and the tartrate of lime formed is 

 decomposed by a slight excess of suljjhuric acid ; no chlorine is now 

 employed to decolorize the liquors, and no trace of parataric acid is 

 now obtained. 



It is stated by M. Kestner that he is entirely ignorant whether 

 the circumstances which he has stated have produced tlie paratartaric 

 acid : he has never been able to produce it, neither by the agency of 

 sulphuric acid, even at high temperatures and heating them for a 

 long time together, nor by the action of chlorine. Nor has he suc- 

 ceeded in extracting it directly from tartar, although the attempt has 

 been made on considerable quantities. 



