as above, the colours they produced were inferior 
to thofe with plain water, the aftringency of the 
logwood, or whatever gives it the property of 
finking black with green vitriol, was entirely 
deflroyed ; it produced not the leafl blacknefs 
with any quantity of vitriol. 
EXPERIMENT lie 
Four penny-weights, of each of the aflringents 
above-mentioned, were tritured in plain water, and 
four others in lime-water ; the meafures of water 
uled were equal to thofe left, after boiling, in the 
laft experiment; and, upon being mixed with 
martial vitriol as in the laft experiment, the 
colours produced, by this means, were fuperior to 
thofe produced by boiling. Thofe tritured in lime- 
water were judged to be the deepeft, which agrees 
with Mr. henry’s experiments ; but we muft 
again except the Logwood, which gave no colour 
by trituration, more than by boiling in lime- 
water. 
EXPERIMENT III. 
All the above mixtures, having been written 
with as inks, and expofed fix months to the air; 
thole boiled in lime-water had failed much ; thofe 
tritured in lime-water, and in plain water, had faded 
a little ; thofe boiled in plain water evidently pre- 
ferved their colour befl. 
Upon flightly rubbing the faded writings, with 
a frefh aftringent liquor, they recovered their ori- 
Vol. LX1V. " H ginal 
