54 On the Ufe of the Oxyds of Iron 
This nitric folution, having been evaporated, to carry off 
moft of the free acid, bs naps became very curdy on the ad- 
dition of lime water. 
It grew thick and white on adding fulphuric aiid yielding 
a copious precipitate of fulphate of lime. One portion of the 
fupernatant liquor upon this precipitate, on evaporation, af- 
forded an extra¢t-like matter; which readily melted, as phof- 
phoric acid does when it is mixed with a little earthy matter. 
To the other portion of this fupernatant liquor was added 
liquid cauftic ammoniac, producing a precipitate which af- 
forded no fulphate of magnefia with fulphuric acid. 
From thefe experiments it appears, that the above 96 grains 
of infoluble matter confiiled of phofphate of lime. Accord- 
ingly, the 300 grains of urinary concretions examined, ap- 
pear to contain, 
grains 
Peculiar animal oxide “ . te 175 
Phofphate of lime . A fy 96 
Ammoniac, (and moft probably phofphoric acid united - 
to the ammoniac,) water, and common mucilage of 
urine, which were not collected and weighed, by 
eftimation - - = 29 
; 300 
[To be continued. ] ; 
—— 
IX. Chemical Confiderations on the Ufe of the Oxyds of 
- Trqn in dyeing Cotton. By J. A. CHAPTAL. Fram the 
Annales de Chimie, Vol, XXVI. 
me 
. ‘I HE oxyd of iron has fuch an affinity with cotton thread, 
that, if the latter, be plunged in a faturated folution of iron in 
any acid whatever, it immediately affumes a chamoy yellow 
colour, more o7 leis dark according to the flrength of the 
liquors, 
=| 
] 
