Mr. Maddrell on the Metaphosphates. 327 



The analysis was made by fusing the salt with carbonate of 

 soda, then by treating the fused mass with water, to sepai'ate 

 the peroxide of iron from the alkaline phosphate, and the 

 phosphoric acid estimated from the loss. 



Found. Atom. Reckoned. 

 Per cent. 



•850 grm. substance gave -224 Fe., 03= 26-353 Fe2 03= 26-767 



POsasloss^ 73-647 3P0g = 73-233 



100-000 100-000 

 Formula, Fca O3, 3PO5. 



Metaphosphate of Oxide of Chromium was obtained by dis- 

 solving oxide of chromium in an excess of diluted phosphoric 

 acid, evaporating, and heating up to the same temperature as 

 before. It is a beautiful green, anhydrous compound, inso- 

 luble in water and concenti'ated acids. 



The analysis was made by fusing the salt with caustic pot- 

 ash ; the fused mass was then digested in water (to separate 

 the oxide of chromium from the alkaline phosphate), filtered, 

 and the filtered solution neutralized with hydrochloric acid. 

 To the solution was added ammonia, chloride of ammonium, 

 and a salt of magnesia, to precipitate the phosphoric acid, 

 and from the precipitate, after being heated to redness, the 

 quantity of the latter was estimated. The CrgOg I was 

 obliged to estimate as loss, as I found it exceedingly difficult 

 to obtain a correct result, it being more or less oxidized by 

 the action of the caustic potash. 



Found. Atom. Reckoned. 

 Per cent. 

 •67 grm. substance gave -772 MgO,P05 = -488 P05 = 72-836 SPOj =72-731 



Crj O3 as loss = 27-164 Cr^ O3 =27-269 

 100-000 100-000 



Formula, Crg O3, 3PO5. 



Metaphosphate of Oxide of Copper was obtained on adding 

 a solution of nitrate of copper to an excess of diluted phos- 

 phoric acid, and evaporating and heating up to the same 

 temperature as before. It is a bluish-white, anhydrous 

 compound, insoluble in water and diluted acids, but soluble 

 in concentrated sulphuric acid. This salt I dissolved in con- 

 centrated sulphuric acid, diluted the solution with water, and 

 precipitated by sulphui-etted hydrogen ; the sulphuret was 

 then redissolved in hydrochloric acid, diluted with water, fil- 

 tered, and precipitated by caustic potash, and the PO5 esti- 

 mated from the loss. 



Found. Atom. Reckoned. 



1*518 grm. substance gave -542 CuO= 35-704 CuO= 35-713 



P05a8loss= 64-296 PO, = 64-287 



lOOOOU 100-OOU 



Formula, CuO, PO5. 



Metaphosphate of Barytes was obtained by decomposing 



