THE 



PHILOSOPHICAL MAGAZINE 



AND 



ANNALS OF PHILOSOPHY. 



[NEW SERIES.] 



MAY 1827. 



LXII On the Orange Phosphate of Lead. By the Rev. 



Wm. V. Veunon, F.B.S. Pres. I.P.S.* 

 TN a former communication which I had the honour of 

 A making to the Society, I stated as the result of some ana- 

 lytical researches into the cause of the diversity of colour ;n 

 the phosphates of lead, that I had found manganese m the 

 green phosphate, and chrome in the orange phosphate trom 

 Wanlock head; at the same time I offered some reasons tor 

 supposing that the chrome in this mineral is in the state ot 



^'^Such a"supposition, however, afforded no satisfactory solu- 

 tion of the orange colour of the phosphate; for though many 

 of the combinations of the chromic acid are yellow or red, and 

 especially its combination with lead, this is not the oase with 

 the green oxide of chrome. , . i.«. ,. t v, 1*1 



For the purpose of clearing up this difficulty, I have lately 

 resumed the inquiry, and made the experiments, of which 1 

 now propose to give the Society an account. 



Upon sixty grains of the mineral I poured nitric acid a little 

 diluted with water, which with the assistance of heat dissolved 

 the whole, except four-tenths of a grain, consisting ot sUex 

 and red oxide of iron. The colour of the solution was a 



golden yellow. . . 111 -ru^ 



Sulphuric acid was now added to precipitate the lead. 1 he 



sulphate of lead weighed 63-4. grains. The liquid after the 



separation of the lead retained its yellow colour. 



I took a third part of this liquid to examine the nature ot 



its contents, reserving the other two-thirds for the deterrama- 

 • Read to the Yorkshire Philosophical Society, March 6, 182G; and 



comniiinicatcd by the Author. r, t' ♦;^r, 



M'W Series. Vol. 1. No. 5. May 1827. 2 T tion 



