Comlinations of different Metals and Chlorine, m. 171 

 «olved in muriatic acid without effervesci^ng, and wiihout 

 Imlrdinc any res-due of brown oxide. Hence the yellow 

 oxce. Head appears to contain 7-15 r^r cent, ot oxvgen 

 AnUhis proporuon of oxygen n. the ox.de compared v^uh 



^/a! ofclHorrne in plumbane, l-^^^-"? V/h!; oTlTs 

 to be in the ratio of 7-3 to 33-8, instead of ^^a of 15 6 



the estimate of Klaproth, - «f .^^-^j'^^ f '^r^^f d bv 

 Thomson, to 33 8. Klaproth might have been mu led by 

 considering the hydrated oxide as a true xvhite ox.de free 



*Tcc?rding to M. Proust the peroxide of anVimony con- 

 tains 23 per cent, of oxygen, and the protoxide 18 . I 

 have repeated this chemist's experiments ; my results in 

 v^hich the peroxide is concerned, ape with h.s ; bu there 

 is not the same concordance in those relat.ng t« the p o- 

 toxide. The protoxide I used was either prepared by the 

 decomposition of the butter of ant.mony, or of the sulphat, 

 by a bo.ling solution of carbonat of potash. 1 h.s oxide, 

 it? its purest Slate, I have always found, as M. I'roust de- 

 scribes it, of a light fawn colour before fusion and a er 

 wards in mass of a gray colour, and ot a radiated crystall me 

 texture. 100 grains of it that had been tused were heated 

 in the state of powder with strong lest n.tr.c ac.d ma 

 platina crucible; when nitrous gas ceased to be produced, 

 the excess of nitric ac.d was expelled by a gentle heat, and 

 the oxide was heated to dull redness, the mcrease ot u eight 

 after this was equal to 10 4 grains; nitric acid was again 

 added and the process repeated, but without any alteration 

 of weight beini produced. Hence, as the peroxide contains 

 23 per cent, the protoxide seems to contain 13 per cent.; 

 which proportion of oxygen very nearly agrees wuh that ot 

 chlorine in the butter of antimony ; tor ant.mony bemg as 

 423, the former is to the btlcr as 75 to 34-6 instead of 

 33-6 I put some confidence in this estimate of the pro- 

 portion of oxvLren in the protoxide, not only on account ot 

 fts acrreeme.u'with the analysis of ihe butter ot antimony, 

 but because it was confirmed on the repetition of the ex- 



perimcnt. . t . »u ^ 'A^ 



Klaproth concludes from his experiments, that the ox.de 

 pf bismuth, prepared by means of nitric acid, contains 17'/ 

 per cent, of oxygen, and in consequence this oxide has been 

 considered distinct fr.HU that which is termed by direct cal- 

 pination of the metal, and which contains a much sma leC 

 proportion. But there is reason to believe thai this dit- 



• Jtiurml dt Physique, torn. Ir. 



ference 



