Chemistry and Physics. 421 
4. On the Absorption of Gases by Carbon.—Though experi- 
ments have been frequently made to determine the volume of 
various gases which a unit volume of charcoal. absorbs, there 
seem to have been very few attempts to determine the compo- 
sition of the gas subsequently given up by the charcoal on heat- 
ing. Baxer has undertaken some experiments to ascertain the 
nature of the gas thus given up by charcoal when it has absorbed 
oxygen. The charcoal examined was that from boxwood and 
animal charcoal; but as the latter, especially after purification, 
absorbed a far larger volume of gas it was used by preference. 
Duplicate experiments were also made; the oxygen being dried 
in one series and saturated with moisture in the other. The car- 
bon was contained in a cylindrical bulb one-quarter to one-third 
of an inch in internal diameter, drawn out to the size of a quill 
at one end. By means of a Sprengel pump the whole was ex- 
hausted, the bulb being heated to a high temperature. After 
cooling, it was attached to a gas pipette, oxygen was allowed to 
enter and to remain at the normal pressure until the absorption 
was complete, the bulb meanwhile being immersed in water or in 
a freezing mixture, at pleasure. The bulb was then exhausted. 
On heating it now to 100° and exhaustion, the gas obtained from 
it could be examined. ‘The author finds: Ist, that moist oxygen 
absorbed at —15° by carbon, is not evolved free or combined at 
12°; 2d, that (a) the water- -vapor and oxygen thus absorbed, 
when kept for a week at 100°, produce carbon dioxide, the char- 
coal giving up 7 times its volume, (4) water vapor and carbon 
kept at 100° for a week produce no carbon dioxide, and (y) car- 
bon and dry oxygen at 100° for a week produce no carbon mon- 
oxide; 3d, that (a) a temperature of 450° is required to remove 
the dry oxygen retained by carbon, carbon monoxide being the 
chief product, (4) the more free from moisture the substances the 
less the oxidation, and hence (y) carbon is burned directly to 
monoxide by the absorbed and firmly retained oxygen.—2/. Ch. 
Soc., li, 249, March 1887. G. F. B. 
5. On the Valence of Bismuth.—The fact is well known that 
the organic compounds of the nitrogen group show in their triva- 
lent combinations a greater intensity in the free bonds than the 
inorganic compounds. Thus while arsenous chloride AsCl, will 
not unite with more chlorine, methyl-arsenous chloride CH, AsCl, 
forms a tetrachloride. Micuaxrris has sought to determine in 
this way the quinquivalence of bismuth. By adding bromine to 
a solution of bismuth-methyl in well-cooled petroleum- naphtha, 
no addition product was obtained. Nor was he able to add 
ethyl iodide to bismuth-methyl. But bismuth-phenyl thus 
treated gave at once triphenyl-bismuth dibromide (C,H,),Bibr, 
and chloride (C,H,),BiCl,, as permanent and well defined com- 
pounds. In these bodies we have for the first time compounds in 
which five univalent atoms or atomic groups are united to a sin- 
gle atom of bismuth; and hence they establish the quinquiva- 
lence of bismuth as certainly as they did that of an CEOny: — Ber. 
Berl. Chem. Ges., xx, 52, Jan., 1887. . F. B. 
