126 
NATORE 
arrangement of the atoms in the group which is repre- 
sented by each point on tke lattice. 
We may consider certain points of more general 
interest. The structure of the diamond stands our 
with some prominence. It is interesting to find that 
the carbon atoms are arranged in the most beautifully 
symmetrical pattern, each being at the centre of a 
regular tetrahedron composed of its four nearest 
neighbours. Rings of six carbon atoms are a pre- 
dominating feature. Planes perpendicular to a cube 
diagonal—the diamond is, of course, a cubic crystal— 
are arranged in a curious way, the spacings being 
alternately large and small in the proportion of three 
to one. This leads to the extinction of the second 
order reflection from these planes. The effect can be 
readily illustrated optically by ruling a diffraction 
grating in the corresponding fashion. Zincblende has 
exactly the same structure as the diamond, but the 
alternate planes of the kind just mentioned contain 
alternately zinc atoms alone and sulphur atoms alone. 
This explains the well-known polarity of the crystal. 
Iron pyrites has a rather more complicated structure, 
which explains at once the curious disposition of the 
striations on its faces. Sulphur has eight interpene- 
trating lattices, quartz three of silicon and six of 
oxygen. In each of these two cases there is regular 
spacing of the lattices along the long axis, but not in 
other directions. 
The atoms of a crystal are not, of course, at rest; 
the extent of their movements depends on thermal 
considerations. As the temperature rises the motion 
increases. According to theory, this must tend to 
destroy the intensity of the spectra, particularly those 
of higher order. Experiment confirms the theoretical 
deduction, and gives some promise of being able to 
decide between conflicting hypotheses as to the extent 
of the thermal influence. 
angles of reflection diminish as the crystal expands 
with heat and the spacings of the planes increase. 
The method might even be applied to the measurement 
of coefficients of expansion of crystals. 
Lastly, the study of the X-ray spectra emitted by 
various substances when made the antikathodes of the 
X-ray bulb gives valuable information respecting 
atomic structure, and is most skilfully made use of 
in the investigations which are being conducted in 
the physical laboratory of the University of Man- 
chester. ; 
UNIVERSITY AND EDUCATIONAL 
INTELLIGENCE. 
Lonpon.—Prof. H. H. Jeffcott has been appointed 
by the Senate to the chair of engineering tenable at 
University College, vacated by the appointment of 
Prof. J. D. Cormack to a professorship at Glasgow. 
Prof. Jeffcott was educated at Trinity College, Dublin, 
and is now professor of engineering in the Royal Col- 
lege of Science, Dublin. ‘ 
The D.Sc. degree in physics has been granted to 
Dr. E. E. Fournier d’Albe, Royal College of Science 
and Birmingham University, for a thesis on the 
efficiency of selenium as a detector of light. 
Evidence is to be presented, on behalf of the Univer- 
sity, to the Departmental Committee of the Board of 
Education in regard to external students, without 
being restricted to the recommendations of the Royal 
Commission. j 
Mr. C. A. KinG has been appointed professor of 
mechanical engineering in the Civil Engineering Col- 
lege, Sibpur, India. 
A FREE scholarship of the value of 30l., tenable at 
the Northampton: Polytechnic Institute (London) is 
being offered to students. In view of the openings 
which the calling and craft of optics now offer, this 
NO. 2308, VOU. 93] 
It is curious to observe the 
[APRIL 2, 1914. 
‘Aitchison Memorial Scholarship,’ should prove most 
attractive to intelligent youths. The subjects of exam- 
ination include English, mathematics, and elementary 
physics. Full particlars can be had of the hon. 
treasurer, Mr. H. F. Purser, 39 Charles Street, Hatton 
Garden, London, E.C. 
A copy has been received from New York City of a 
volume entitled ‘‘A Study of Education in Vermont 
prepared by the Carnegie Foundation for the Advance- 
ment of Teaching at the request of the Vermont Edu- 
cational Commission.’’ The legislature of Vermont 
on November 19, Ig12, appointed a commission to 
report on the educational responsibilities of the State. 
On February 24, 1913, the commission invited the 
Carnegie Foundation to undertake an expert study of- 
the school system of the State, including the higher 
institutions of learning. The resulting report pro- 
vides much information and enumerates the conclu- 
sions and recommendations of the foundation. Among 
other recommendations the withdrawal of State sub- 
sidies from all higher institutions not owned and con- 
trolled by the State is suggested. Three colleges are 
now subsidised by the State of Vermont, and these 
have some 1026 students, 565 of which are provided 
by Vermont itself, while 400 Vermont students attend 
colleges in other States. There are in every thousand 
of population in Vermont three students of higher 
education. In connection with the University of Ver- 
mont, one of the institutions aided by the State, 
strong courses in the humanities and in the sciences 
are recommended, as well as the development by the 
University of the State Agricultural College. 
THE general and departmental reports for the ses- 
sion 1912-13 of the Bradford Technical College reveal 
a satisfactory growth in the usefulness of the institu- 
tion. There was an increase in the attendance over 
the previous academic year. The arrangement under 
which advanced students in dyeing from the Leeds 
University attend a course in the practical dyehouse at 
Bradford was in work during the session. A number 
of Bradford students also attended special courses of 
lectures at the Leeds University. This reciprocal 
arrangement, having proved satisfactory, is being 
continued. The head of the department of textile 
industries reports that although no large increase in 
the number of day students is to be expected, it is 
worthy of note that attendance in the department 
forms a ready entrance into the higher walks of the 
textile industries in the case of students of ability who 
lack special influence in the trade. He points out 
also that the raising of the standard of attainment 
in the industry is possibly the most important work 
of the college evening classes, and those who have 
followed this development recognise the help which 
the college has rendered to the textile trade of the 
city in this direction. The work of the materials test- 
ing laboratory of the department of engineering is 
growing at a rapid rate, and at the present time more 
than one thousand tests per annum are being made 
for the various Government and corporation depart- 
ments, and for local firms. This has the effect of 
bringing the work of the department into close touch 
with the engineering trade of the district, and a 
number of interesting problems of a practical char- 
acter are forthcoming, in the solution of the majority 
of which the students are permitted to take part. 
SOCIETIES AND ACADEMIES. 
LOnpDon. 
Royal Society, March 26.—Sir William Crookes, 
president, in the chair.—J. H. Mummery: The nature 
of the tubes in marsupial enamel and its bearing upon 
enamel development. In the present paper the author 
<a e 
