218 
NATURE 
[APRIL 22, 1915 

tunity for the determination, and the result obtained is 
here described. The photograph secured showed two 
strips of spectra of ‘the corona at the east and west 
limbs, and, as comparison spectra, three other strips 
of spectra of diffused sky light were secured sym- 
metrically on the same plate ten minutes after the 
eclipse. The resulting wave-lengths of the coronal 
line for the east and west limbs were found to be as 
follows, each wave-length being the mean of five com- 
plete series of measures entirely distinct :— 
East \ 6374-43 (Rowland) 
West A 6374-59 aS 
Diff. 
This. difference corresponds to a velocity of 3-7  kilo- 
metres, and, making a correction for the inclination 
of the slit to the solar equator, gives an equatorial 
velocity of about 3:9 kilometres per second, a value 
correct to about 25 to 30 per cent. In the eclipse ot 
1898 Prof. Campbell, using the green radiation, de- 
duced a tangential velocity of 3-1 kilometres a second 
(+2 km. nearly), the diffuse nature of the radiation 
preventing further accuracy. M. Bosler points out that 
the corona moves in the same direction as the surface 
of the sun, and appears to rotate more quickly. The 
higher levels of the chromosphere show a similar 
tendency only to a less degree. An apparent increase 
in velocity with the elevation is thus proved. 
o-16 
Tue ANNUAL OF THE BuREAU DES LonGITUDES, IgI5. 
—The very useful annual for the current year pub- 
lished by the Bureau des Longitudes is as compact as 
ever, and Contains a mine of valuable information very 
handy for reference. Besides the usual numerous 
tables useful to the astronomer, several new communi- 
cations are included. Thus M. G. Bigourdan writes 
on the subject of the constellations, and after a brief 
historical sketch gives the co-ordinates of the principal 
stars and star charts down to 50° S. latitude. Quite 
a long article, devoted to stellar spectra and their 
classification, is written by M. A. de Gramont. The 
author describes Secchi’s classification with illustra- 
tions of the type spectra, and then refers to more 
recent classifications, giving a table showing the corre- 
spondence with each other. Sir Norman Lockyer’s 
classification is dealt with in a separate section of the 
article, and is compared with the Harvard College 
Observatory classification. A very valuable article, 
covering 162 pages, is that on ‘‘ Methods of Examina- 
tion of Mirrors and Objectives,’ contributed by M. 
Bigourdan. The article is illustrated by a large num- 
ber of very useful figures, which will considerably help 
the reader. The preliminary chapter includes numer- 
ous historical references, and this is followed by 
chapters on general methods of examination, their 
application to all reflecting surfaces, the examination 
of mirrors mounted in telescopes, and, finally, a very 
complete account of the examination and testing of 
objectives, 
CHINESE REcoRDs oF EcripsEs.—In the Proceedings 
of the Tékyé Mathematico-Physical Society (January, 
1915, vol. vili., No. 1) Messrs. Kiyotugu Hirayama 
and Sinkiti Ogura discuss the interesting records of 
early Chinese eclipses. Their working list extends 
from the earliest solar eclipses to those recorded in the 
Ch‘un Ch‘iu. In the case of the latter, the calculations 
are in progress, and are expected to be soon finished. 
In the present communication the general plan of the 
calculations consists in determining the central line 
and the limiting lines for each eclipse. The eclipses 
of Shu Ching and Shih Ching are dealt with, and 
diagrams are given showing some of the limits of 
visibility. 
NOW12373, VOL.05] 

TEACHING OF ENGINEERING IN 
EVENING TECHNICAL SCHOOLS. 
HE ‘‘ Memorandum on the Teaching of Engineer- 
ing in Evening Technical Schools” (Circular 
894), recently issued by the Board of Education, is a 
very welcome manual of suggestions to teachers and 
organisers of schools which provide evening classes in 
mechanical and electrical engineering. 
This Memorandum fills nearly sixty foolscap pages, 
and is divided into nine sections. An introductory 
section points out the limitations of part-time courses 
—courses intended for students whose ordinary em- 
ployment ‘occupies the greater part of their time— 
when compared with tull-time day courses. The 
second section, after referring to the fact that some 
of the serious disadvantages which characterise part- 
time courses conducted in the evening may be avoided 
by the growing practice of holding such courses 
during the day (the junior employees being allowed 
“time off’ in order to attend them), proposes to 
classify ‘“‘a complete curriculum of evening instruc- 
tion’’ into three stages: the junior course (fourteen 
to sixteen); the senior course (sixteen to eighteen or 
nineteen), and the advanced course (eighteen or nine- 
teen to twenty, twenty-one, or twenty-two). Senior 
courses are to be of two kinds: a minor course, com- 
plete in itself, for apprentices to engineering trades; 
and a major course, incomplete unless it also includes 
an advanced course, for technical men. The third 
section of the Memorandum gives outlines of typical 
major (senior and advanced) courses in mechanical 
and electrical engineering, and of minor (senior only) 
courses in some engineering trades. After making, 
in the next section, some valuable suggestions upon 
laboratory and class instruction for adolescent evening 
students, the Memorandum proceeds, in the following 
four sections, to consider in more detail the teaching 
of the various subjects which constitute these outline 
courses. The accommodation and equipment required 
for the various classes of work already discussed are 
considered in the ninth and final section, 
The Memorandum is thus concerned with all kinds 
of evening classes intended for persons employed in 
engineering work, from the apprentice who is begin- 
ning to learn a trade to the designer or manager who 
attends a course of evening lectures delivered by a 
university professor. By concentrating attention upon 
evening classes as such, and especially upon those 
classes which are primarily intended for boys and 
young men between sixteen and twenty-two years of 
age, the Board’s inspectors have succeeded in produc- 
ing a document which cannot fail “to assist teachers 
and organisers to mark out for themselves the schemes 
of instruction best suited to the conditions of their 
classes.” But this very concentration, to which the 
Memorandum owes much of its usefulness, will dis- 
appoint education committees or directors of educa- 
tion who look to find in it some treatment of the 
wider educational and economic problems of engineer- 
ing training, such as the following :—The selection, 
on democratic lines, of the most suitable boys for each 
different type of training which should be provided for 
the different positions in engineering industry; the re- 
spective parts to be played,in the preparatory (full- 
time) training of engineers, by the elementary school 
and the junior technical school, the lower secondary 
school and the senior technical school, and the higher 
secondary school and the university or technical col- 
lege; the point at which works training should begin; 
the co-ordination of practical experience in the shops 
with instruction in classes inside the works and with 
outside schools and colleges; and, more generally, the 
effective co-operation between engineering firms and 
