338 Dr. Macneven's Exposition of [Nov. 



Article III. 



Hxpositiojiofihe Atomic Theory of C/iemistrt/ ; and the Doctrine 

 of Definite Proportions. By William James Macneven, M.D. 

 Professor of Chemistry and Materia Medica in the College of 

 Physicians and Surgeons of the University of the State of 

 New- York. 



{Concluded from p. 293.) 



59. Silver. — According to Vauquelin, a protosulphuret of 

 silver is composed of lOU metal + 14-59 sulphur. Hence the 

 protoxide of silver must contain 7-29 oxyo;en nearly + 100 silver. 



There is but one oxide of silver known, composed, according 

 to Thomson, of 7-291 oxygen + 100 metal. Hence, by the 

 canon of Berzelius, this must be the protoxide. Therefore, as 

 7-29 : 100 :: 1 (atom ox.) : 13-71 weight of an atom of silver. 



60. Gold. — Berzelius obtained two oxides of gold, the second 

 containing three times the oxygen contained in the first. 



First oxide '. . 100 gold -{- 4-005 ox. 



The peroxide 100 + 11 -982 



Hence as the difference is 8 in this progression, oxygen cannot 

 combine with gold according to any other term above unit than 

 the first, which is, therefore, a binary, composed of one atom of 

 gold + one atom oxygen. We have, therefore, this proportion 

 to determine the weight of an atom of gold as 4-005 : 100 :: 1 : 

 24-96. 



The peroxide is a quaternary, as it consists of 1 atom gold + 

 3 atoms oxygen. 



61. Platinum. — From the experiments of Mr. Cooper, it fol- 

 lows tiiat 100 parts of platinum combine with 4-423 oxygen; 

 jhence the atom of platinum must weigh 22-625. 



62. Palladium. — Berzelius determmed the only known oxide 

 of palladium as composed of 100 palladium + 14-209 oxygen. 

 If this be a protoxide, the atom of palladium will be 7-03, for 

 14-209 : 100 :: 1 : 7-03. 



But if we suppose the sulphuret of palladium, as found by 

 Vauquelin, to consist of 100 metal + 24 sulphur, and to be a 

 protosulphuret, then the atom of palladium would be represented 

 by 8-338 for 24 -- 2 : 100 :: 1 : 8-333. 



63. Rhodium. — There are three oxides of rhodium, composed, 

 as determined by diffeient analyses, of first, 100 metal + 6-71 

 oxygen; the second, 100 metal 4- 13-42 oxygen ; the third, 100 

 metal + 20-13 oxygen. Now 6-71, 13-42, and 20-13, are to 

 each other as 1, 2, 3, and consequently the first is a protoxide, 

 and 6-71 : 100 :: 1 : 14-9, or nearly 15 weight of the atom of 

 rhodium. 



64. Iridium. — The oxides of iridium have not been determined ; 



