ore REPORTS ON THE STATE OF SCIENCE, 
may be concluded that in neutral solvents, such as benzene and chloro- 
form, no change can occur unless some third substance or impurity is 
present ; the influence of the impurity may be greatly increased by 
raising the temperature or illuminating with ultra-violet light ; but even 
under these conditions it is probable that isomeric change is not a 
spontaneous result of the interaction of solvent and solute. 
The experimental evidence thus gives no support, but on the contrary 
is entirely opposed to the existence of the condition of intermolecular 
‘wobble’ postulated by Laar! in his theory of ‘tautomerism.’ It is, more- 
over, very doubtful whether even the special case of the process of ‘ bond- 
shifting,’ or ‘desmotropy,’? which does not involve the transference of 
a mobile hydrogen atom, and which Baly* has described as ‘ isorropesis,’ 
could occur in pure neutral solvents in the absence of a catalytic agent. 
In addition to the investigation described above, considerable attention 
has been paid during the past year to the study of the optical properties 
of dynamic isomerides, and preparations have been made for a detailed 
examination of the relationship between the absorption spectra of iso- 
dynamic compounds and the velocity with which they undergo isomeric 
change. 
The Study of Isomorphous Derivatives of Benzene-Sulphonice Acid.— 
Report of the Committee, consisting of Professors H. A. MIErRs 
(Chairman), H. EK, Armstrona (Secretary), W. P. WYNNE, and 
W. J. Pore. 
Tue task undertaken is the preparation of all the possible isomeric 
sulphonic chlorides and sulphonic bromides of the isomeric dichloro., 
the isomeric dibromo-, and of the isomeric chlorobromo-benzenes and to 
subject them to crystallographic study with the object of determining 
the extent of variation in the series of closely related compounds. 
Apart from the labour entailed in measuring such a series, which is 
very great, much difficulty arises both in devising suitable methods of 
preparing the compounds and in obtaining properly developed crystals. 
It has not been found to be possible at present to prepare one of the 
three sets of 1: 3:5 derivatives and one of the two sets of 1:2:3 
derivatives. In the case of the 1 : 4 : 2 derivatives, whereas six of the 
eight compounds crystallise with the greatest readiness, the seventh is 
obtained only with difficulty in measurable forms ; all attempts to grow 
measurable crystals of the eighth have been failures. 
It is possible that the new conceptions introduced by Barlow and 
Pope may afford a clue to such peculiar differences. The investigation 
has certainly acquired increased importance in view of their conclusions, 
and will therefore be pushed forward during the coming year. 
With the cbject of contrasting oxygen with sulphur, p-methoxy- and 
p-ethoxy-benzene-sulphonic chloride and bromide and the corresponding 
thio-compounds have been prepared and partially measured. The rela- 
tionship between the corresponding oxygen compounds and between the 
corresponding thio-compounds appears to be of a simple character, only 
one axis being affected in the passage from the methyl to the ethyl com- 
pare ; the effect of the displacement of oxygen by sulphur is less simple, 
owever. 
1 Ber., 1885, 18, 648-657. 2 Jacobson, Ber., 1888, 21, 2628. 
* Stewart and Baly, Trans, Chem. Suc., 1906, 89, 498, 
