650 Royal Society, 



acid was deemed to be complete. The acid liquid was then saturated 

 with ammonia, some chloride of ammonium and sulphate of magnesia 

 then added, and the mixture well shaken. It was allowed to stand 

 for some time, when a precipitate of phosphate of magnesia and 

 ammonia was formed ; this was washed, dried, and ignited, and the 

 amount of phosphorus calculated from the result. These are the 

 results. 



Grms. C0\ HO. 2MgO, PO*. 



• 2405 aether gave • 3 7 84 and • 1 9 20 



•5115 „ -8047 and -4155 



•4513 „ „ „ ^302 



•4110 „ „ ,. -278 



From these results the following per-centages are calculated. 

 Required. Found. 



C«« 4311 42-91 42-89 



H'* 8-98 8-87 9-03 



P 19-16 18-92 19-10 



06 28-75 29'30 28-98 



100-00 100-00 100-00 



These results being satisfactory as regards the formula, the den- 

 sity of the vapour was then ascertained and found to be in strict 

 accordance with theory. The method of taking the vapour densities 

 of bodies liable to oxidation was described by me about twelve months 

 ago, in the Chemical Society's Quarterly Journal. It was used in 

 the following experiments. 



1st. Weight of globe filled with air at 53° F. and 30*2 in. baro- 

 meter, 188-213 grs. 



Weight of empty globe, 186-313 grs. 



Weight of globe and vapour at 521° F. and 30-3 in. barometer, 

 192-387 grs. 



Capacity of globe at 60° F., 6 00 cub. in. 



Residual hydrogen -05 cub. in. 



Capacity of globe at 521° F., 6-40 cub. in. 



Six cubic inches of air at 53° F. and 30-2 in. barometer, become 

 at 60° F. and 30 in. barometer 6-12 cub. in., and weigh 1-90 gr. 



•05 cub. in. hydrogen at 60° F. become -094 cub. in. at 521° F., 

 and weigh -002 gr. 



6-40— -094=6-306 cub. in. vapour at521°F., which at 60°F. 

 and 30 in. barometer =3-376 cub. in. 



Hence 192-387--002=192-385-186-313=6-072 grains, the 

 weight of 3-376 cub. in. vapour. 



100 cubic inches. . =179-86 grs. 

 100 cubic inches air= 31-01 grs. 



The density is therefore 5-800, from which it appears that its com- 

 bining measure is four volumes. 



Density by calculation =5-763. 



A second experiment gave 5-877. 



This substance has a highly offensive odour, it burns with a bluish ' 



