504 REPORT—1904. 
when treated with acids gave rise to a mixture which was found to consist chiefly 
of diphenyl and benzoin. The former is very readily produced from phenyl 
magnesium iodide, and is frequently observed among the products of its reactions. 
ee eter of benzoin has an important bearing on the constitution of nickel 
carbonyl, 
All the reactions of nickel carbonyl which have been described previously can 
be equally well explained by means of either of the two formulz 
G2 “9 CO—CO 
7 =C=0 : 
Ni G=0Q and NiC | 
which have been proposed; but benzoin could be produced in a much simpler way 
from a compound with the second formula, Its production may therefore be 
regarded as evidence in favour of this, 
The following suggestion as to the course of the reaction is to be regarded as 
purely tentative : — 
C,H, OMgI 
a 
/o—CO eK ZOMel 
Ni | + 4C,H—Mg—I > Ni | CO.H, 
CO—CO C—C/C,H, 
we \OMel 
C,f, OMel ; 
| H,O and acid 
C,H; JOH 
2C,H,—CHOH A 
C_c/oH 
ck a 00 ei NiK |\C.Hs 
+ nickel salt, C—C/C,H 
/\._ Soil 
'6**5 OH 
The product 
C,H, >C—OH 
C,H; >C—OH 
is supposed to undergo molecular transformation into benzoin, 
11. A Suggested Explanation of the Phenomena of Opalescence observed in 
the Neighbourhood of Critical States, By F. G. Donnan. 
It has been frequently observed (Guthrie, Rothmund, Friedlinder, Kono- 
walow) that a mixture of two liquids becomes opalescent before the temperature 
is reached at which definite separation into two phases occurs. Similarly, a 
mixture of two partially miscible liquids remains opalescent at temperatures beyond 
that corresponding to the disappearance of the meniscus. Apparently analogous 
phenomena have been noticed in the case of one-component liquid-vapour systems, 
especially by Wesendonck and Teichner. The latter has observed the existence 
of permanent opalescent states in the case of carbon tetrachloride at temperatures 
several degrees higher than the critical. These phenomena, so far as they 
refer to mixtures of liquids, have been studied by Konowalow, who considers that 
they are due to a partial separation into two phases, occurring round dust-nuclei 
acting as centres of disturbance. Konowalow shows that such a disturbance of 
equilibrium in the otherwise homogeneous liquid will, in the neighbourhood of the 
critical solution temperature, involve only a slight expenditure of work owing to 
. the small change of vapour-pressure with composition under these conditions, 
