ren 
324 Tanning Principle and Gallic Acid in Barks. 
who may be inclined to inyeftigate this fubject more ney 
a very accurate feale may hereafter be formed. 
In the following feale, I bave taken Sumach as the moft” 
powerful in the comparative ftatement ; leaving, however, a 
jew degrees for a /uppofed maximum of tanning principle, 
which I reckon twenty. 
SCALE OF BARKS, 
Tanning pr inciple, 
G: Mic acid, Tanning prin- (in grains,) from 
by colour.’ ciple, by by- half a pint of infus — 
: “aR 4 drometer, fion and an ounce 
Bark of ‘ of folution of gle. 
Rl 8 1829) este ty 2,1 28 | 
Oak, cut in winter 8 yy i 30 
Horfe cheftnut - 6 252 30 
Beata abr ten 2,4 31 
Willow (boughs) 8 24 31 
Pricey Ae ep aie ti TY, 330 41 
Plum-tree - - 6- 4,0 58 
Willow (trunk) - 9 ‘4,0 52 
evcaitioré =) = 6 Be 53 
Bir@l! Pye Ss) 'Sa4 4yI 54 
Cherry-tree -. + ° 8 45 59 
Sallow)< F)3. LoRg 4,0 59 
Mountain afh - 8 4,7 60 
Pooldr’) 20-9" 8 6,0 76 
Hazel. - = = 9 6,3 79 
ARey ras ao Oe Gy 6,6 82 
Spanilh cheflaut. - 10 *G.0 : g8 
Snisoth oak’ == to 9,2 104 ; 
Oak, cut in [pring 10 950 108 
Huntingdon or Lei- sh 
cefter willow .- 10 10,1 10g 
Sumach- - -~"- 34 16,2 - 158 
It is to be obferved, that the barks do not keep any re- 
fpeStive proportion in the quantity of gallic acid and tanning. 
principle contain-d in each; which is an evidence of the 
* The i: fufion of elm was fo loaded with mucilage that it was with 
@. fficuity £ I could Leparate the tanning principle, or try the fpecific gravity. 
J diflinéinefs 
