58 



applied to the large quantities of corn which were unavoidably housed 

 in a damp state, in consequence of the unpropitious weather, during 

 the late harvest. The author considers the mustiness to be confined 

 principally to the exterior amylaceous part of the grain, and the pro- 

 cess proposed consists in pouring upon the tainted grain thrice its 

 quantity of boiling water. When cold, the water and floating grains 

 are to be poured off; the corn is to be washed with cold water, 

 drained, and carefully kiln-dried. It will be found perfectly sweet, 

 and the loss of weight is inconsiderable. 



The advantages of this process are its simplicity and cheapness ; 

 and although the author has hitherto only applied it to wheat, there 

 can, he observes, be little doubt that oats and other grain may be 

 deprived of must with equal success. 



Observations on an astringent Vegetable Substance from China. By 

 William Thomas Brande, Esq. Sec. R.S. Read December 12, 1816. 

 \Phil. Trans. 1817, p. 39.] 



The substance described in this communication was sent to Sir 

 Joseph Banks as a species of galls, used by the Chinese in dyeing 

 black. They have the appearance of irregular vesicles, of a purely 

 astringent flavour, and closely agree with those described by Du Halde 

 under the name of on poey tse, which are also employed in China as 

 the bases of many astringent medicines. 



By digestion in cold distilled water, these galls yielded a pale 

 brown infusion, of a highly astringent taste, and furnishing a copious 

 white precipitate with solution of animal jelly : 100 parts thus yielded 

 78 of soluble matter, which, when obtained by evaporation, was of a 

 brown resinous appearance ; and, though only slightly sour to the 

 taste, powerfully reddened the infusion of litmus. 



The author remarks that the perfect solubility of this part of the 

 galls in cold water, and its pale colour, indicate that the tannin it 

 contains is nearly, if not perfectly, free from extractive matter ; and, 

 by pursuing the usual processes, he succeeded in obtaining it in a con- 

 siderable state of purity. The tannin thus afforded is also soluble in 

 alcohol ; whence, if previous experiments be correct, it is analogous 

 to the tannin of catechu, but distinct from that of galls, which is 

 said to be insoluble in that menstruum. 



When all soluble substances in water were removed from the Chi- 

 nese galls, the residuum afforded to alcohol a minute portion of re- 

 sinous matter, and 23 per cent, of insoluble woody fibre then only 

 remained. 



A further examination of the aqueous infusion proved it to con- 

 tain gallic acid in considerable proportion ; and the method which 

 best succeeded in its separation, consisted in adding lime water to 

 the cold aqueous infusion of the galls, which produces a precipitate 

 composed of tan and lime, and leaves a gallate of lime in solution, 

 which, when cautiously decomposed by oxalic acid, furnishes oxalate 

 of lime and gallic acid nearly, but not perfectly, pure. The author 



