existing in the Nut-galls of the Oak. 405: 
what whitish, and with a slight odour analogous to that of the 
ei], as has been observed by many of my friends and pupils to 
whom I have shown it. After settling, there appeared in the 
bottoms of the bottles in which I had placed these distilled fluids 
some very small white particles, but the pieces of paper used for 
filtering them, when exposed to heat, did not yield any sensible 
odorous vapour. 
I believe that I do not deceive myself in saying, that no notice 
relative to this concrete volatile oil is to be found in Chaptal’s 
Elements of Chemistry, in Deyeux’s Memoir* on the rut- galls 
of the oak, in Fourcroy’ s System of Chemical Knowledge, 1 in the 
Chemistry. of the Encyclopédie Meéthodigue, nor in Thomson’s 
Chemistry. It is true, Bouillon Lagrange in his Faits pour 
servir a [ Histoire de [ Acide gallique, published in 1806, has 
observed, that when this acid is extracted from galls by the me- 
thod of Deyeux, that is by sublimation, it contains a small quan- 
tity of volatile oil, which he considered merely as a product of 
the sublimation ; saying, “it cannot be doubted that there is 
formed in the liquor some acetic acid, which acting on a portion 
of tannin and extractive matter, constitutes the gallic acid of 
Scheele ; but this combination becomes more intimate, and even 
varied, by the aid of caloric. We have a proof of it when we ob- 
tain this ‘acid by means of sublimation; not only the tannin is 
decomposed, but the acid remains combined with a volatile oil 
which is formed ¢.”’ In confirmation of this, I have not found 
any mention made of a volatile oil, as a constituent part of the 
nut-galls of the oak, in any work subsequent to the publication 
of this memoir ; such as, among others, Brugnatelli’s Chemistry 
and Pharmacopezia ; Klaproth and W, olff’s Chemieal Dictionary; 
the Annotations of Professor Morelli; Thenard’s Chemical Trea- 
tise, published last year in Paris; and lastly, Sir Humphry 
Davy, who has recently analysed these galls without speaking of 
any volatile oil contained in them. The latter found that 500 
grains of Aleppo nut-galls yielded 185 grs, of soluble matter, 
which was composed of tannin 130; gallic acid united with a lit- 
tle extractive matter3! ; mucilage ‘and matter rendered insoluble 
by the evaperation 12; carbonate of lime and a salive sub- 
stance 12; add to these, the ligneous part when burnt contained 
much ealcareous carbonate t. , 
Notwith- 
* Ann. de Chimie, xvii. 3. According to this author, Aleppo galls are 
composed of # mucous body, of a true extractive matter, of a pa ticular kind 
of resin, of a green colouring part, of gallic acid, and a ligneous tissue. Af 
terwards he observes that it is possible that other substances may have 
escaped his research. + Ann. de Chimie, \x. 180. ‘ 
t Thenard, Traite de Chimie, iii. 343. Note by the Translator. This oil 
keeps very well in a properly-stopped bottle, is of the consistence and co- 
Cc3 lour 
