Chemical Science. 229 
Acetic acid - 2 proportionals 50 x2=100 i = 180. bi-per- 
Peroxide of copper 1 ditto = 80 acetate. 
Aceticacid . 1 ditto = 50 2 =130 perace- 
Peroxide of copper 1 ditto = 80 tate. 
Aceticacid . 1 ditto = 50 2 =210 subper- 
Peroxide ofcopper2 ditto 80 x2 =160 acetate. 
To shew that verdigris agrees in composition with the blue 
silky crystals above analyzed, Mr. Phillips has given the fol- 
lowing analysis of French and English verdigris : 
French Verdigris. English Verdigris. 
Agetio wes: p55). 6h) hai PBB! as QOG2 
Peroxide of copper . . . 43.5 . . 44.25 
Petar PO eh! sal ah BDA: on OS GE 
Aamprand ty a Oy fede aids. Yoon nD. < eh thw O62 
100.0 100.00 
(Phillips's Annals. No. 21.) 
4. Black Enamel obtained from Platinum.—Mix a solution 
of muriate of platinum with one of neutral nitrate of mercury, 
and expose the precipitate to a heat sufficient to drive off the 
protochloride of mercury: you will obtain a black powder, 
which, applied with a flux, produces a fine black enamel. (An- 
nales de Chim. et Phys. xx. p. 198.) 
The above extract from the Annales de Chimie et Physique, 
for June 1822, is evidently derived from Mr. Cooper’s paper, 
which appeared in this Journal in the year 1817. (See Vol. III, 
p- 119.) 
5. Test for Magnesia.—In the Annales de Chimie for May 
last, it is stated, that if we spread any clear liquid upon a 
plate of glass, and then trace the word Magnesia upon the 
glass so covered, with the end of a glass rod, that word will 
appear in white characters if magnesia be present in the solu- 
tion; if not, no such appearance will result. It is, moreover, 
stated, that this method of discovering the presence of magne- 
sia originated with Dr. Wollaston, and was communicated to 
the Editors by M. Clement. 
In the same journal for July, M. Clement writes as follows 
' to the Editors: 
“ Gentlemen,—In your number for May last you have given 
a very inaccurate report of a neat experiment which Dr. Wollas- 
ton was so kind as to show me when in London. The preci- 
pitation upon the written characters only ensues when the 
magnesian solution has been previously decomposed by a mix- 
ture of phosphate and carbonate of ammonia. ‘This substance, 
re-dissolved by the excess of carbonate, is precipitated upon 
9 
a” 
