290 M. Braconnot on Sorbic Acid. [Oct. 



admit the existence of another principle, which has a fishy odour, 

 and which he conceives to be identical with an odorous principle 

 which he has discovered in the cartilage of the Squalus peregri- 

 nus. This substance is peculiarly developed when it exists in 

 combination with ammonia or an ammoniacal salt, and the salt 

 is mixed with caustic potash. It may be doubted, whether the 

 leathery odour of the saponified oil of the Delphinus and common 

 fish oil, and the colouring principle which exists in so consider- 

 able a quantity in these oils when they have been long kept, are 

 proximate principles simply disengaged, or the result of some 

 alteration which the principles that were extracted from these oils 

 have undergone, or depend upon some other principles which 

 have hitherto escaped detection. 



Article VI. 



On the Sorbic Acid and its different Combinations. By M. Henri 



Braconnot.* 



The author had been led to conclude that malic acid, as it is 

 usually obtained, is not pure, and had attempted to obtain it 

 from the malate of zinc, a substance said by Seheele to form 

 very beautiful crystals ; but he found that the acid thus procured 

 differed essentially from the malic. He was endeavouring to 

 ascertain the exact nature of these differences, when Mr. Dono- 

 van announced his discovery of the sorbic acid. M. Braconnot 

 objects to the method adopted by Mr. Donovan, both as being 

 one by which the acid is obtained in small quantity only, and in 

 an impure state. M. Braconnot recommends the following 

 process : the fruit of the Sorbus Aucuparia is to be taken before 

 it is quite ripe, and is to be bruised in a marble mortar and 

 strongly squeezed. It must then be boiled, and carbonate of 

 lime must be gradually added until all effervescence ceases ; it 

 is then to be evaporated to the consistence of a syrup, the froth 

 being carefully removed as it continues to form. The sorbate of 

 lime is quickly precipitated in the form of a granulated salt ; the 

 supernatant fluid is to be poured off, the salt washed in cold 

 water, and dried with a linen cloth. The salt ha& a slight yellow 

 tinge, which indicates that it is not pure ; it is, therefore, to be 

 boiled for a quarter of an hour, with an equal weight of crystal- 

 lized sub-carbonate of soda diluted with water. A neutral sorbate 



* Abridged from Ann. de Chim. et Phys. vi. 239. It is probable that the expe- 

 riments of M. Braconnot and those of ML Vauquelin are to be regarded as equally 

 original, and that they mu9t have been performed about the same time. M. Bra- 

 connot's paper was read to the Royal Society of Sciences at Nancy, in November, 

 1817 ; and M. Vanquelin's paper wa? published in the number of the Ann. de 

 Chimie et de Physique for the following month. 





