342 
LETTERS TO THE EDITOR. 
(The Editor does not hold himself responsible for opinions 
expressed by his correspondents. Neither can he undertake 
to return, or to correspond with the writers of, rejected 
manuscripts intended for this or any other part of NATURE. 
No notice is taken of anonymous communications.] 
Science at Oxford and Cambridge. 
I HAVE read with great interest Prof. Perry’s article on 
“* Oxford and Science ’’ and his letter in NaTure of January 
21, and assuming as I do that his remarks apply equally 
to Cambridge, I know that he has in no way overstated his 
case. There are one or two effects of the present system 
which I feel that he has scarcely brought out sufficiently 
strongly, and on which I lay the more stress, as I consider 
that they are harmful in more ways than one. 
I well know the asphyxiating atmosphere of which he 
speaks, and I compare it to that of a septic tank the con- 
tents of which are reduced in time to the form of an 
innocuous but useless effluent. Had they been spread out 
over the country at large they would have been of value in 
raising up a fertile growth of scientific progress. 
The university professor is generally in a position to dis- 
regard the apathy of his university, and to pursue researches 
for their own sake. In the case of the enthusiastic student 
who is desirous of embarking on a career of teaching com- 
bined with research, the effects of the present system are 
far more deadly, especially if he belongs to a small college 
where the medizval atmosphere is usually most con- 
centrated. 
In the present day it is generally 
possible it is always highly inexpedient, that a man should 
devote his energies to research, pure and simple, without 
taking some part in the educational work which is being 
carried on all around him. But the man who, after taking 
a brilliant degree in arts or science, seeks to associate him- 
self with the teaching and examining work of his college 
or university, frequently finds himself baulked at every step 
by the opposition of a hostile but influential clique, although 
he is being continually urged by his friends to remain at 
the university in the hope that he may ultimately obtain that 
recognition which is freely conferred on men of less origin- 
ality. Although the dons of his college will not raise a finger 
to help him, they do everything in their power to dissuade 
him from engaging in such outside work as a man without 
teaching experience has a reasonable prospect of obtaining 
in these days of competition. When a good professorship 
falls vacant, they write testimonials belauding his original 
work, of which they know nothing, but his candidature | 
breaks down as soon as questions are asked about his teach- 
ing experience. 
[A striking contrast to this spirit is seen in the excellent 
work done by certain well organised departments, such as 
the Cavendish Laboratory and a few enlightened colleges.] 
What I have attempted to describe is not the experience 
of a single individual; from the number of-cases that have 
come before my notice I feel sure that it must be a common 
experience. 
I now pass to the other side of the question. When a 
vacancy occurs in a university college, it frequently happens 
that there is one candidate whose brilliant distinctions place 
him far above his rivals, and whose appointment would in 
all probability greatly conduce to the success and welfare 
of the department of which he would have charge. The 
electors would gladly appoint him if any definite evidence 
could be adduced as to his capability of discharging the 
duties required of him, but failing such evidence “they are 
obliged, after a long and protracted discussion, to choose 
the second candidate on their list. 
I know men who have broken through the barrier, both 
from Oxford and from Cambridge. I am glad to have such 
men as colleagues, for I know that they are doing splendid | 
work in raising up a high standard of university education | 
throughout Greater Britain. | 
| 
impossible, and if 
Our university colleges have not been afraid to establish 
scholar assistantships in departments in which the work is 
too heavy for the existing staff. Why should not the same 
procedure be adopted at Oxford and Cambridge? This | 
would often enable the colleges to give their best graduates | 
NO. 1789, VOL. 69] 
NARORE 
[FEBRUARY II, I904 
a good send-off into the world, and it would relieve the 
present teaching staffs of much burdensome routine work. 
We might even have college tutors waxing enthusiastic 
over scientific research ! G. H. Bryan. 
The Radiation from an Electron moving in an Elliptic, 
or any other Orbit. 
I HAVE been looking for a tolerably simple way of ex- 
pressing the radiation at a distance from an electron, to 
avoid the work involved in reducing the general formulz 
(Nature, November 6, 13, 1902) in special cases. The 
result is 
B=#Q S sin y, (1) 
4mr 
subject to 
R=v(t—-4). (2) 
Here understand that Q is the charge moving in the path 
defined by the vector s from the origin at the moment t,, 
and E is the electric force at the corresponding moment t 
at the point P at the end of the vector r from the origin, at 
distance R from Q, and vy is the angle between r and s. 
That is, the electric force is the tangential part of the vector 
SuQ/4rr, or the part perpendicular to r. The magnetic 
force is perpendicular to E, given by E=pvH. It is 
assumed that s/R is very small, but no assumption has 
been made about w/v, so the waves are fully dopplerised. 
The dot indicates time-differentiation at P. 
Example. Elliptic orbit. Let 
s=1(n, cos #f, +52, sin nt,). (3) 
n 
Then Q describes an ellipse in the plane x,y, axes u,/n 
and u,/n, where n/2m is the frequency. It is the spring or 
pendulum kind of elliptic motion. Describe a spherical 
surface with centre at the centre of the ellipse, and project 
s upon the surface, and insert the result in (1). Then we 
get 
Ee nQ cos 6 2 (1 COS @ COS #¢, +2, SiN p sin nt), (4) 
4nrn at 
EE® 2s sin @ cos 7¢, — 2, cos ¢ sin nt) (5) 
4mrn dt?\ ~ 
expressing the @ and @ components of E at the point 
r,9,o, if @ is measured from the s axis, and » from the 
plane s,x. 
Yet one thing more. 
nt, =n(¢ ae 
D 
which gives 
‘fee 
which is required when (4) (5) are differentiated. This 
process introduces the factor t,3, and so, at high speeds, 
converts the radiation into periodic pulses, as in the case 
of a circular orbit (NaTuRE, January 28, p. 293). Put 
u,=u,=—u in the present formule to reduce to the circular. 
The analysis to simply periodic vibrations may be done in 
a similar way. If the motion in the elliptic orbit is of the 
planetary kind, the equation (3) is replaced by a much less 
manageable one. Electrons can conceivably vibrate in both 
these ways, according as the centre of force is condensed 
positive electricity, or is the centre of diffused positive 
electricity. 
This is not the place for detailed proofs, but I can indicate 
one way of representing the matter which has some interest 
apart from the speciality of orbital motion. Given that QO 
The connection between ¢ and f, is 
sin 6 
My COS M COS wt, +2, Sin > sin nt), (6) 
= zh. -1 
a 2%, SIN } COS 77%, — 2g COS H Sin nt,)} a (GA) 
is moving anyhow, it may be shown that my general 
formula for E may be converted to 
Oe Qz 
B="<R,++4 2 (B- 3RR,+ oR, ) (8 
47 
This gives E at P, at distance R from Q, and R, is the 
unit vector R/R. The centre varies as we _ shift P, 
because Q is moving. It is always to be understood 
