606 Intellifience and Miscellaneous Articles, 



'to 



M. Fr^my has discovered the substance which, according to the 

 views generally admitted, ought to have the name of anhydrous 

 tartaric acid. He obtains it with great facility, for it is sufficient 

 to expose tartaric acid to the action of heat in a capsule. The acid 

 fuses, loses water, swells up, and leaves a spongy mass which con- 

 sists mostly of anhydrous tartaric acid ; it is so sparingly soluble in 

 water, that this fluid dissolves from it the tartaric acid, which has 

 not been completely deprived of water. 



It is well known that the composition of racemic or paratartaric 

 acid is similar to that of tartaric acid. In all destructive re- 

 actions, tartaric and racemic acids undergo similar alterations, so 

 that up to the present time nothing is known which explains the 

 differences that may exist in their rational formulae. M. Fremy sub- 

 jected paratartaric acid to the same treatment as that by which he 

 obtained anhydrous tartaric acid, hoping that some difference 

 would appear in this way between these two bodies ; none how- 

 ever occuiTcd. Paratartaric acid behaved like tartaric acid, and 

 yielded an analogous substance, which must be considered as an- 

 hydrous paratartaric acid. 



Connected with these facts, which are sufficiently remarkable on 

 account of the two acids obtained, M. Frdmy communicated two 

 others, which on account of their novelty, have strongly excited 

 the attention of those who are engaged in the development of or- 

 ganic chemistry. 



In fact it is not anhydrous tartaric acid which is directly produced 

 by the fusion of tartaric acid. Before it arrives at this condition, 

 common tartaric acid gives rise to two intermediate products, of 

 great interest as regards theory. The first is tartralic acid, the se- 

 cond the tartrelic acid of M. Fremy. The tartralic acid is repre- 

 sented by tartaric acid, which, instead of saturating two atoms of 

 base, saturates only | atoms. Tartrelic acid is represented by 

 tartaric acid, which saturates only one atom of base. So that com- 

 mencing with the most probable formula for tartaric acid* C"^ H^ 

 01°, 2H'^ O, or C'^' H'2 0'2, it will be seen that the three products 

 in question will be represented as follows, in their respective salts 

 of lead. 



C'6H« 0'«, 2PbO tartrate. 

 C16 H8 O'o, |PbO tartralate. 

 CiG H8 O'", PbO tartralate. 



M. Fr^my has thus ascertained, that in proportion as tartaric acid 

 loses water, it gives rise to bodies which combine with smaller 

 quantities of base, and which form salts with bases equivalent to the 

 proportions of water which they retain. These modifications recall 

 those which have been assigned by Professor Graham as the causes of 

 the variations which phosphoric acid and the phosphates undergo by 

 the action of heat. The author has satisfied himself that the tar- 

 tralic and tartrelic acids readily return to the state of tartaric acid. 



The reporter observes that it results from the experiments of 



* These are the formulae in the original. 



