84 hiteUigence and Miscellaneous Articles. 



Forty parts of this acid having been exposed for an instant to a 

 considerable heat, ihey fused, swelled up, and left after cooling a 

 dry yellowish matter, which was transparent like guna, and weighed 

 36-5 parts. This substance when softened by heat acquired great 

 ductility, which allowed it to be drawn into threads as fine as 

 hairs. 



This change of form, which recalls the dimorphism of sulphur, 

 shows either a new molecular arrangement, or another isomerical 

 modification. In fact, the tartaric acid thus submitted to the 

 action of heat, no longer possesses its original properties; it is un- 

 crystallizable, and is merely a thick viscid mucilage, which attracts 

 moisture from the air. 



If this substance be dissolved in hot water, and carbonate of lime 

 be gradually added to saturate it, it does not form, as with com- 

 mon tartaric acid, a sandy deposit of crystallized tartrate of lime, 

 but the solution becomes gradually turbid as it cools, and deposits 

 a mucilaginous transparent insipid mass, which forms threads be- 

 tween the fingers like turpentine. This calcareous salt when dried 

 is unalterable in the air, and resembles gumarabic. When heated 

 in water or weak acetic acid, it softens, resuming its viscid and 

 adhesive properties, without being sensibly dissolved; an excess 

 of acid, however, redissolves it, especially when hot, and by evapo- 

 rating the solution to dryness, there remains a dry brittle acidulous 

 substance, which is transparent like a varnish, is unalterable by the 

 air, and which when immersed for some time in cold water seems 

 to undergo a molecular motion, which reproduces tartaric acid in 

 its original state, for then there separates a sandy deposit of com- 

 mon tartrate of lime. 



Tartaric acid modified by heat, also dissolves magnesia and yields 

 a bitter liquor, which leaves a varnished surface by evaporation. 

 Crystallized tartaric acid acts quite differently with this earth, for 

 it immediately precipitates a white powder, which is difficultly so- 

 luble in water; the same modified acid, saturated with soda, pro- 

 duces an uncrystallizable mucilaginous combination, which attracts 

 moisture from the air. 



With potash an analogous result is obtained; and if to the com- 

 pound an acid be added in excess, a very greatly divided precipitate is 

 formed, as difficultly soluble as tartar, but which has not its granular 

 appearance. When redissolved in hot water, it gives by cooling 

 white opake plates, in which rudiments of crystals are scarcely 

 discernible ; this acidulous salt when saturated with soda gives a 

 salt analogous to Rochelle salt. Although tartaric acid, when ex- 

 posed to heat, is not a very permanent isomeric substance, it 

 evinces at least a remarkable tendency to this state. — Ann. de 

 Chim. et de Phys. xlviii. 299. 



FORMATION OF CARBONATE OF LIME UNDER THE INFLUENCE 

 OF SUGAR. BY M. PELOUZE. 

 IVIr. Daniell concluded from his experiments, that when lime is 

 dissolved in an aqueous solution of sugar, the sugar i:^ decom-^ 



