Aucust 27, 1914] 
in a variety of ways corresponding to the allocation of 
one particular sodium atom to either of six chlorine 
atoms; the alternative modes of partitioning lead to 
the production of molecular units of identical con- 
figuration. In many cases, however, alternative 
methods of geometrically partitioning the assemblage 
representing the crystalline structure do not yield units 
of the same configuration; thus, the assemblage re- 
presenting phloroglucinol can be geometrically parti- 
tioned in two distinct ways. Each of these gives a 
unit of the composition C,H,O,, but the configuration 
of the unit of the one partitioning corresponds to the 
chemical structure of the 1: 3: 5-trihydroxybenzene, 
,C(OH) . CH 
Se a Sc(OH) 
Nc(ou): ca” 
whilst the other exhibits the structure of the sym- 
metrical triketohexamethylene, 
CO. CH, 
HCC Sco. 
‘CO. CH,” 
A new suggestion is thus made to the effect that 
tautomerism consists in the possibility of geometrically 
partitioning the close-packed assemblage in two or 
more alternative ways, each giving molecular units of 
the same composition but of different constitutions. 
The idea that in the occurrence of tautomerism some 
component atom wanders from one position to another 
in the molecule is thus rejected; the change in con- 
stitution arises from the transference of atoms as 
between two or more molecules. As the older concep- 
tions of the mechanism of tautomerism do not provide 
a satisfactory explanation of the experimental facts, 
the suggestion now made is perhaps worthy of con- 
sideration. 
The new line of work has many bearings upon the 
subject of chemical change; thus, the assemblage 
which is assigned to acetylene (or methylacetylene) 
is convertible, by symmetrical distortion, into that 
representing benzene (or the 1: 3: 5-trimethylbenzene, 
mesitylene. Further, the great change in chemical 
behaviour which accompanies many types of chemical 
substitution is possibly connected with the manner in 
which the actual atomic volumes are affected by the 
replacement; on converting benzene, in which the 
atomic volumes of carbon and hydrogen are as 4:1, 
into bromobenzene, a considerable’ increase in mole- 
cular volume occurs. The atomic volumes of carbon 
and hydrogen still, presumably, preserve the 4:1 
ratio, and the volume appropriated by the entering 
bromine atom is approximately the same as that 
occupied by each hydrogen atom already present; the 
actual atomic volumes of carbon and hydrogen must 
thus be supposed to have increased during the pro- 
duction of bromobenzene. It can hardly be supposed 
that this fundamental volume change, even apart from 
a distortion of the aromatic ring arising from slight 
inequality of hydrogen and bromine atomic domains 
in the molecule, could occur without the exhibition 
of considerable differences in chemical properties as 
between benzene and bromobenzene. 
Whatever view may be taken as to the accuracy of 
the conclusions concerning the relation between crystal 
structure and chemical constitution which are briefly 
discussed in the present address, no critic will be dis- 
posed to doubt that wide developments in chemical 
science will result from the cultivation of crystal studv: 
it seems clear that any satisfactory theory of the solid 
state must be largely crystallographic in character. 
The chief hindrance to progress at present consists 
Hew2739, VOL. 93] 
NATURE 
685 
in the lack of chemists trained in modern crystallo- 
graphic methods; in my own country the only school 
in which chemical students were trained in crystallo- 
graphy, dissociated from mineralogy, was founded by 
Dr. Henry E. Armstrong and Sir Henry A. Miers in 
1886. After doing a vast amount of valuable educa- 
tional work this school has recently been allowed to 
become extinct. 
In a presidential address to the Mineralogical Society 
in 1888, Mr. Lazarus Fletcher remarked that ‘‘a know- 
ledge of the elements of crystallography, including the 
mechanics of crystal measurements, ought to be made 
a sine qua non for a degree in chemistry at every 
university.’ Twenty-five years later we find that no 
European university has applied this principle, and in 
consequence the chemical crystallographer has the 
greatest difficulty in making himself intelligible to his 
purely chemical colleagues. May I, in concluding, 
express the hope that the colonial universities, less 
fettered by tradition than their older sisters, may lead 
in the work of placing the subject of crystal structure 
in its legitimate position as one of the most important 
branches of modern physical chemistry ? 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE. 
GLasGow.—The Principal wishes it to be known 
that the University will do what it can to safeguard 
the academic interests of undergraduates on military 
duty. In relation to attendance on courses of instruc- 
tion, to duration of study, to periods of notice re- 
quired, etc., account will be taken of a student’s 
absence on military duty to ensure, if possible, that 
his graduation shall not be unduly delayed. 
Tue authorities of the Royal Agricultural College, 
Cirencester, wish it to be known that every endeavour 
will be made to prevent students who are undertaking 
army or other patriotic work from being thereby 
penalised as regards their courses of study. 
Tue Vice-Chancellor of the University of Liver- 
pool states that. although the Council and Senate 
have not met since the declaration of war, it may 
be assumed (1) that the University courses will 
begin on the appointed day; (2) that in due time 
everything will be done that can be done to safeguard 
the interests of members of the staff and of students 
who have offered themselves for national service 
at home or abroad. It is also announced that at 
Durham University the term will begin as usual in 
October, and that no member of the Durham Colleges 
will suffer any academic disability by reason of absence 
on any form of national service. 
Tue fifty-fifth annual report of the Cooper Union for 
the Advancement of Science and Art has been received 
from New York. The union governs and finances 
many departments of higher education, and in the 
report its director gives full particulars of the work 
done during the year ending June, 1914, and directs 
special attention to the development of the technical 
school. We notice the resignation of Prof. Robert 
Spice, after twenty-five years’ service in Cooper Union 
as professor of chemistry and head of the department 
of chemistry. Since 1900 Prof. Spice has devoted the 
whole of his time to the Cooper Union; beginning with 
some twenty students the attendance has steadily in- 
creased until now the limits of the capacity of his 
department have been reached. 
