306 * Royal Society :— 
atomie weight is nearly 3; while for phosphorus, arsenic, anti- 
mony, and bismuth, the product thus obtamed is twice as great, 
or about 6. In this respect, however, osmium probably resem- 
bles nitrogen—the latter examined, as it necessarily is, in the 
gaseous form. 
It is to be hoped that the conducting power for heat and elec- 
tricity of compact osmium will soon be examined ; nothing is as 
yet known of these characters. 
Lastly, as regards the magnetic relations of the element : it is 
placed, with some doubt, by Faraday in the paramagnetic class ; 
the metal and its protoxide were found to act feebly in this 
sense, while pure osmic acid is said to have shown itself clearly 
diamagnetic. The strongly diamagnetic character of phospho- 
rus, antimony, and bismuth would render a re-examination of 
this point interesting. Arsenic, however, is said to be very 
feebly diamagnetic, and is placed by Faraday close to osmium 
in the list of metals examined, though on the opposite side of the 
line of magnetic neutrality or mdifference. 
Reviewing, now, the united physical and chemical characters 
of osmium, and comparing them with those of the generally re- 
cognized members of the “ arsenic group,” we are, I think, jus- 
tified in concluding that here this curious metal should be placed 
in a natural arrangement of the elements; while important di- 
stinctions seem to separate it from some, at least, of the platimum 
metals, with which it is usually associated and described. 
XLI. Proceedings of Learned Societies. 
ROYAL SOCIETY. 
(Continued from p. 235.] 
Nov. 17, 1859.—Sir Benjamin C. Brodie, Bart., Pres., in the Chair. 
ele following communications were read :— 
«« Researches on the Phosphorus-Bases.’”’—No. VI. Phospham- 
monium-Compounds. By A. W. Hofmann, LL.D., F.R.S. &e. 
In several previous communications I have shown that dibromide 
of ethylene is capable of fixing either one or two molecules of tri- 
ethylphosphine, a monatomic and a diatomic bromide being formed, 
which I have respectively represented by the formulaee— 
Monatomic bromide.- ©, H, 
C,, H,, PBr,= (C, H,)" Br,+ (C,H), P=| 6° ti Br 
Br) 
Diatomic bromide, [6G H,); " 
C,, H,, P, Br,= (C, H,)" Br, +2 ((C, Hi), rE) +3 i H : a 
and 
