254 ON SOME N.S.W. TAN-SUBSTANCES. 



varying with the period of the year, and the variety of the tree 

 whence they where obtained, (Jour. Soc. Arts 1884). Leaves of 

 different trees (oaks) exhibit considerable diversity in their yield 

 of tannin. The tannin of the leaves is identical with the bark. 

 Oser (Chem. Centr. 1875, 517) makes reference to the fact that 

 the green leaves of the oak contain a considerable quantity of 

 quercitanic acid, so that they would prove a good material for 

 tanning purposes. 



13. Quercus tinctoria, Willd., (Cupulifera?). "Quercitron 

 leaves." " Avec le quercitrin coexiste assez souvent le tannin, 

 quelquefois l'acide gallique, matieres qui ont avec lui ce caractere 

 commun de donner une couleur brune avec les sels de fer. A cote 

 du quercitrin ou en son absence, on trouve aussi la quercetine et 

 la meline. (Bolley, Stein). Ces matieres, quercitrin, tannin, 



acide gallique &c ont une diffusion ou generalite 



d'existence tres differente ; le quercitrin est le plus repandu ; le 

 tannin 1' est beaucoup moins ; 1' acide gallique est rare." (Chatin 

 et Filhol, Comptes Rendus lvii., 39). Pendant la coloration 

 automnale des feuilles, les matieres qui colorent les sels de fer 

 disparaissent, et leur destruction a lieu dans 1' ordre suivant : 

 quercitrin, tannin, acide gallique. Cet ordre de destruction est 

 le meme que celui de leur diffusion, qui est sans doute celui de 

 leur importance physiologique." (loc. cit.) 



14. Fagus sylvatica, Linn., (Amentifera 1 ). Beech leaves. The 

 leaves were gathered in 1 England on the 26th of each month, 

 except November 7th. They yielded tannic 'acid per cent. : — 

 June, 1-164; July, 1-804; August, 2-395; September, 2*93 ; 

 October, 2-802 ; November, 3-576. (Journ. Chem. Soc, xxviii., 

 1279). Beech leaves gave 20'8 per cent, of extract to Wanklyn. 



15. Spirea tomentosa, Linn., (Rosacea?) of New England, U.S.A. 

 Called " Hardback." The leaves and young shoots are rich in 

 tannin, and once in three years the plant is mowed, cured, and 

 sold to the tanners at prices which afford a fair profit for the use 

 of the land. (Monthly Reports of Depart, of Agric, Washington, 

 1873, p. 35). 



16. Tea. — -Chinese Green (Hyson) 17*8 per cent. Chinese 

 Black (Congou) 12*88 per cent. Java Green (Hyson) 17-56 per 

 cent. Java Black (Congou) 14*8 per cent. (Mulder in Watts' 

 Diet.) Hassall gives 18*69 per cent, for green tea and 15*24 per 

 cent, for black. S. Jauke, using the copper acetate process, finds, 

 taking 18 samples of black tea, the maximum to be 9*142 per 

 cent., the minimum 6*922 per cent., and the mean 8*1. Of three 

 samples of green tea 9*94 the maximum, 8*56 the minimum, and 

 9*57 the mean. Wigner gives the percentage of tannic acid in 

 some astringent teas he examined at from 27*7 to 42*3. Hill 

 (Analyst, 1881, p. 95 - 99) gives 14*8 per cent, as the average of 

 32 samples of black and green tea. 



