33° 
there is far too much apathy on this question among 
men of science and the general public, yet a great 
deal is being done on scientific lines to effect greater 
efficiency in the utilisation of fuel. Probably nothing 
but economic pressure will make the public at large 
abandon the present wasteful methods which were 
indicted by Prof. Armstrong. A minor feature of 
the meeting was the number of chemical papers read 
in other sections: this is an inevitable consequence 
of the splitting up of the sections of the association 
during the last decade. The spread of chemistry is 
satisfactory, if it be regarded as a sign of the 
growing appreciation of the subject by biologists and 
others; but, on the other hand, it leads to state- 
ments being made and accepted without comment 
which would be criticised drastically by an audience 
of chemists. 
The section welcomed Prof. Feist (Kiel), Prof. 
Sérensen (Copenhagen), and Prof. Tschugaeff (St. 
Petersburg) at its meetings, and had the pleasure of 
entertaining them to dinner on the Saturday evening. 
After Prof. W. P. Wynne had delivered the presi- 
dential address on substitution, Mr. P. K. Dutt gave 
a brief account of work carried out with Prof. J. B. 
Cohen on the progressive bromination of toluene 
in which the orienting effect of the various mono- and 
di-halogen compounds has been studied; the results 
were contrasted with those obtained by chlorination. 
Dr. R. S. Morrell described his recent work on the 
saturated acids of linseed oil which he has identified 
as stearic acid and palmitic acid with a trace of oleic 
acid. The great difficulty experienced in the quantita- 
tive separation of the fatty acids was emphasised. 
In a discussion of the paper, attention was directed to 
the necessity from the biological point of view of a 
more complete study of the fatty acids. 
Dr. Tinkler made a communication on a series of 
mixtures of nitro compounds and amines which are 
coloured only in the liquid state, which he illus- 
trated experimentally. Mixtures of diphenylamine 
with certain nitro compounds give solutions which 
are coloured at one temperature but become colourless 
on cooling. Thus a mixture of diphenylamine and 
parachloronitro-benzene acquires a_ reddish-yellow 
eolour when held in the hand, and loses this colour 
when the temperature falls. The colour is considered 
due to the combination of nitro-compound and amine 
in the liquid state only. Various physico-chemical 
investigations of the fused mixtures were undertaken. 
Mr. E. Vanstone dealt with the influence of 
chemical constitution on the thermal properties of 
binary mixtures of benzoin .with other organic com- 
pounds which had been studied by the usual methods 
of thermal analysis. 
A short paper by Mr. H. Ehrhardt established the 
fact that anthranilic acid is formed by the decom- 
position or over-reduction of indigo in the bisulphite- 
zinc-lime vat. Some remarks on the influence of the 
presence of gas upon the inflammability of coal-dust 
in air by Prof. W. M. Thornton completed the day’s 
programme. 
Optical Properties. 
The morning of Friday, September 12th, was de- 
voted to a series of papers dealing with the signi- 
ficance of optical properties. The first, by Dr. R. H. 
Pickard and Mr. J. Kenyon, concerned the optical 
rotatory powers and dispersions of the members of 
some homologous series of organic compounds. 
More than one hundred opticaily active compounds 
belonging to ten such series have been synthesised. 
Although they possess simple and closely related 
constitutions, no numerical relationship between their 
rotatory powers-has yet been detected. Well-marked 
regularities are shown which are more or less common 
NO. 2298, VOL. 92] 
NATURE 
Q 
| NOVEMBER 13, I913 
to all the series. A comprehensive account of the 
present state of the knowledge of optical activity was 
given by Dr. Pickard. + 
Rotatory dispersion was the subject of Dr. Lowry’s 
paper. Formerly measurements of optical rotation 
were made with the light of one wave-length only, 
but it is necessary tomake them over a range of wave- 
lengths, especially in the case of substances which 
exhibit anomalous rotatory dispersion. The methods 
of measuring rotatory dispersion have been greatly 
simplified by Dr. Lowry, so that they present no 
difficulty. Use is made of the green and violet mer- 
cury lines, of sodium and lithium, and also of the 
red and green cadmium lines. The curve of rotatory 
dispersion for organic liquids was shown to have 
an extremely simple form. It is expressed by the 
equation 
Ke 
W=Ae? 
where K is the rotation constant and A,” the disper- 
sion constant for the substance. If a is plotted 
against A,?, the curve is a simple rectangular hyper- 
bola. If 1/a is plotted against A*, the curve becomes a 
straight line. 
Prof. L. Tschugaeff followed with a paper on 
anomalous rotatory dispersion, of which there are 
three different types. These were dealt with by the 
reader at some length. The shape of the dispersion 
curve is largely influenced by constitutive factors, the 
whole curve resulting from the superposition of 
several partial curves. The relative positions of the 
centres of activity and of the chromophor groups 
within the active molecule are of much influence, 
The influence of varying factors on the rotatory dis- 
persion of the optically active xanthates was compared 
with that of the tartrates. There is an intimate 
analogy in the origin of the anomaly in both cases. 
Prof. P. F. Frankland directed attention to another 
part of the subject, namely, the so-called Walden 
inversion. He gave an account of researches carried 
out with W. E. Garner to determine the nature of 
the action of thionyl chloride on lactic acid and ethyl 
lactate. In each case the action was very com- 
plicated, but the investigation is throwing light on 
the process of substitution in optically active com- 
pounds. 
Dr. T. S. Patterson directed attention to the rota- 
tion of active compounds as modified by temperature, 
colour of light, and solution in indifferent liquids. 
It has been found that the rotation of certain com- — 
pounds reaches a maximum at a definite temperature. 
This may indicate that one of the groups attached to 
an asymmetric carbon atom attains to a maximum 
influence. The theory is extended to afford a reason 
why anomalous dispersion should exist. The influence 
of the solvent in shifting the temperature-rotation 
curves so as to bring the parts in the neighbourhood 
of the maximum into view was demonstrated. 
Unfortunately, time did not permit of a discussion 
of the views represented. . 
Lieut.-Col. J. W. Gifford described a partially cor- 
rected fluor-quartz lens for spectrum photography of 
a very high degree of accuracy. Dr. J. Hulme made 
a brief communication on crystalline-liquid substances. 
Utilisation of Fuel. 
The subject of the proper utilisation of coal and 
fuels derived therefrom was introduced before a large 
attendance by Prof. Armstrong, who urged that coal 
was burned wastefully and wrongly, and that certain 
issues ought to be brought prominently before the 
public. He deplored the exclusion of the chemist from 
the gas industry until quite recently, and considered 
gas and coke production should be associated in every 
a 
