Volume 2

A system of chemistry of inorganic bodies / By Thomas Thomson.

  • Thomson, Thomas, 1773-1852.
Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: A system of chemistry of inorganic bodies / By Thomas Thomson. Source: Wellcome Collection.

    69/968 (page 51)
    This conclusion was considered as hasty, as he did not attempt to account for the very striking difference in the taste and smell of these acids, as he had neither repeated nor refuted the expe- -riments of Berthollet, on which the opinion of the difference between these two acids was founded. ‘The conclusion of Adet was opposed, in 1798, by Chaptal, who published aset of expe- riments on the same subject.* This philosopher endeavoured to demonstrate, as Berthollet had done before him, that acetic and acetous acids, even when of the same strength, possess dif- ferent properties, and have different effects on other bodies. From the effect of sulphuric acid upon each, and from the quan- tity of charcoal which remains in the retort when equal quan- tities of each saturated with potash are distilled, he concluded that acetous acid contains a smaller proportion of carbon than acetic acid. And this he considered as the cause of the differ- ence in their properties. ) In 1800, a new set of experiments on the same subject was published by Mr. Dabit of Nantes.t+ This chemist endeavoured to prove that acetic acid contains a greater proportion of oxygen and sulphuric acid, the product was acetic acid; but when he substituted muriatic acid for sulphuric, he obtained acetous acid: but when to this last mixture a little black oxide of manganese was added, he assures us that he obtained acetic acid. And in none of these cases was there any carbonic acid emitted till towards the end of the distillation. The experiments of Darracgq at last finally settled this anaes -by demonstrating that acetous and acetic acids differ merely in concentration. ‘This able chemist repeated the experiments of -Adet, which he found perfectly accurate, and performed several new ones; all of which left no doubt that acetous and acetic acids contain precisely the same proportion of oxygen. He next tried the opinion of Chaptal respecting the proportion of carbon in each. When equal quantities of acetic and acetous acids are combined with potash or soda, the dry salts distilled leave the same quantity of charcoal, and yield the same quan- tity of other products. When reduced to the same specific gravity, the two acids form precisely the same salts with all alkaline and earthy bases.. Finally, acetous acid gradually becomes acetic acid when distilled repeatedly off dry muriate of lime; and in this case no. gaseous body whatever is evolved. * Ann. de. Chim, xxviii. 113. + Ibid. xxxviii. 66. Class I,