18 VINEGAR, CIDER, AND FRriT-WIXES. 



Plutarch state that Hannibal dissolved the rocks impeding his 

 march across the Alps by ordering his soldiers to pour vinegar 

 upon them. 



Although there can be no doubt that vinegar was in very 

 general use at an early period, there was until very recently no 

 definite knowledge as to the cause of its production and the mode 

 of its formation. The alchemist Gerber, who lived in the eighth 

 <>entury, was the first to make known the process of increasing 

 the strength of wine-vinegar by distillation, and Albucases 

 (about 1100) stated the fact that vinegar to be colorless has to be 

 distilled over a moderate fire. Basil ins Valentinus, a monk and 

 celebrated alchemist of the 15th century, knew that by the slow 

 distillation of vinegar, first a weak product, and then a stronger 

 one is obtained, and he was probably also acquainted with the 

 process of obtaining strong acetic acid by distilling copper 

 acetate (verdigris). In fact for a long time this was the only 

 mode of preparing acetic acid, the product of the further rectifi- 

 cation of the liquid being termed radical vinegar, spiritm Veneris, 

 Venus'* vinegar, spiritm aeruninis, etc. 



Stahl and Westendorf were the first to prepare the acid in a 

 pure state, and Lauranguais, in 1 759, discovered the property of 

 very strong acetic acid to crystallize at a low temperature. 

 Loewitz, however, in 1793, was the first to obtain it as a pure 

 hydrate (glacial acetic acid). 



The formation of an acid body in the dry distillation of wood 

 was already known in the 17th century. However, it was for a 

 long time not recognized as acetic acid, but considered as a special 

 acid (pyroligneous acid). Fourcroy and Vauquelin, in 1800, 

 were the first to recognize this acid as acetic acid, and Thenard, 

 in 1802, demonstrated the presence of acetic acid among the pro- 

 ducts formed in the dry distillation of animal substances. 



Berzelius, in 1814, determined the exact chemical constitution 

 of acetic acid, and Saussnre, in the same year, that of alcohol. 

 Dr. J. Davy observed that spongy platinum, in contact with 

 vapor of alcohol, l>ecame incandescent and generated acetic acid. 

 Dobereiner further studied the nature of the acid, and proved 

 that the alcohol was oxidized at the expense of the' atmospheric 

 air, producing acetic acid and water, and that no carbonic acid 



