100 
INA T OfeeE 
[ DECEMBER 3, 1896 
From the Sfectator, with an 
Cat and Bird Stories. 
Pp. xill + 
introduction by John St. Loe Strachey. 
279. (London: T. Fisher Unwin, 1896.) 
STORIES of animal intelligence are interesting, and they 
are of value in considering the relations between habit 
and instinct, and the question of reasoning power, when 
they can be trusted. But accurate observers are few, 
and sentiment often causes a simple fact to be buried in 
anthropomorphic imaginings, so that stories have to be 
taken cu grano, and the identity of the writer must be 
known before their scientific value can be appraised. 
We must, therefore, demur to the authors remark that 
“the bird and other stories in the present volume... 
have a distinct scientific as well as a literary value. 
They are not merely good reading, but the record of 
important facts in Natural History.” Many of the letters 
are, however, anonymous, and they have been reprinted 
without asking permission of the writers. No man of 
science would have the temerity to cite irresponsible 
anecdotes from a collection got together in this way, as 
evidence of animal intelligence. The stories are no 
doubt entertaining, but the less that is said about their 
scientific value the better will naturalists be pleased. 
The sub-title of the volume is worth preserving. It 
states that to the cat and bird stories are added “ sundry 
anecdotes of horses, donkeys, cows, apes, bears, and 
other animals, as well as of insects and reptiles.” 
Handbook of Courses open to Women in British, Con- 
tinental, and Canadian Universities. Compiled for 
the Graduate Club of Bryn Mawr College. By Isabel 
Maddison, B.Sc., Ph.D., assisted by Helen W. Thomas, 
A.B.,and EmmaS. Wines,A.M. Pp.iv+155. (New 
York : The Macmillan Company.) 
THE need of a handbook defining the position of uni- 
versities in regard to the admission of women to their 
courses, has been strongly felt ever since the movement 
for the higher education of the gentler sex began. In 
the volume before us the need is admirably supplied. 
From the book, women graduates who desire to continue 
their studies abroad, and students who wish to know 
where they can attend courses and where receive degrees, 
can derive all the information they require as to methods 
of admission, cost of living, names of professors and 
lecturers, &c. It will be to women what the invaluable 
“Minerva Jahrbuch der gelehrten Welt” is to every one 
desiring information on institutions for higher education. 
We notice that Queen’s College, London, is omitted 
(though it has a charter), while King’s College is in- 
cluded. As it is proposed to publish a new edition 
annually, the omission may be put right in the next 
issue. 
Ostwald s Klassiker der Exakten Wissenschaften, Nos. 
76-79. (Leipzig: Wilhelm Engelmann, 1896.) 
PROF. OSTWALD’S reprints of physical classics are too 
well known to need recommendation. Four volumes 
have recently been added to the series, viz. :— 
No. 76: “Theorie der doppelten Strahlenbrechung, 
abgeleitet aus den Gleichungen der Mechanik,” by F. E. 
Neumann (1832), edited by A. Wangerin. 
No. 77: “Uber die Bildung und die Eigenschaften 
der Determinanten,” by C. G. J. Jacobi (1841), edited by 
Pastackel.) 
No. 78: “Uber die Functionaldeterminanten,” by C. 
G. J. Jacobi (1841), edited by P. Stackel. 
No. 79: “Zwei hydrodynamische Abhandlungen.” 
(1) “Uber Wirbelbewegungen” (1858). (2) “ Uber dis- 
continuirliche Flussigkeitsbewegungen” (1868), by H. 
Helmholtz, edited by A. Wangerin. 
The editorial remarks are very full in each case, and 
they add to the value of a unique series of republished 
scientific papers. 
NO. 1414, VOL. 55 | 
LETTERS TO THE EDITOR. 
(The Editor does not hold himself responsible for opinions ex- 
pressed 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 ts taken of anonymous communications. | 
Production of X-Rays. 
OBSERVERS who use Wimshurst machines should remember 
that part of their difficulty in obtaining X-rays with a steady 
current and low vacuum may lie in a peculiarity of the machine 
itself, viz. that it will not work well when short-circuited. 
Machines with permanently charged armatures do not suffer 
from this defect, though certainly it does appear that a given 
quantity delivered in jerks is optically more effective than the 
same quantity delivered smoothly. But this seems to be a 
physiological rather than a physical fact, because I do not find 
it true photographically. The easiest plan to get a jerky current 
is to use what I have elsewhere called a B-circuit—attachments 
to outside of jars,—and the bulb is then, as Mr. T. C. Porter 
says, almost objectionably brilliant. OLIVER J, LopcGe. 
Responsibility in Science. 
UNDER the above heading, Mr. C. Chree wrote to protest 
against some remarks in my address to Section D of the British 
Association, which met recently at Liverpool. Having only 
just returned to England, this is my first convenient oppor- 
tunity of replying to his letter, which appeared in NATURE of 
October 15 (p. 572). 
Mr. Chree objects to the view that ‘‘ physicists as a body” 
have accepted Lord Kelvin’s and Prof. Tait’s conclusions as to 
the age of the earth. Ina matter of such great importance and 
interest, and one which has courted criticism for so long a time 
and on occasions of such exceptional prominence, it is probably 
fair to conclude that, with the great majority of physicists, 
“silence gave consent.” Furthermore, many distinguished 
physicists have expressly told me that they could find no flaw 
in the case, 
If Lord Kelvin and Prof. Tait express a strong opinion, if 
this opinion is quoted again and again, and is only criticised 
by geologists and. zoologists, no physicist saying a word, it is 
likely enough that the geologist and zoologist may come to 
entertain an exaggerated notion of the amount of support con- 
ceded to the opinion by the whole body of physicists. 
The point does not seem to me to be a very important one ; 
and I do not imagine that ‘* physicists as a body ” will be much 
aggrieved because I assumed that they agreed with Lord Kelvin 
on this point. 
Mr. Chree then proceeds to impute to me various opinions 
which I do not hold, and supports the imputation by finding, 
in my address, a ‘‘ strong flavour” of views which only exist 
in his imagination, or by asking whether I believe some opinion 
which I never expressed, and which he then goes on to demolish. 
Thus, I never said, or implied, or believed that ‘‘a solid is 
rigid in the mathematical sense,” or that ‘* electrical and thermal 
conductivity necessarily... vary together.” I understand that 
Prof. Schuster’s conclusion as to the high internal electric con- 
ductivity szgges¢s a high thermal conductivity, and no more than 
this can be got out of my address; and this, I have reason to 
believe, is an opinion shared by Prof. Schuster himself, and 
probably by the majority of physicists. 
The author also takes some pains to show that other forces 
besides the tides have influenced the rate of the earth’s rotation. 
He might have spared himself the trouble. I was not writing 
a treatise on the subject, but attempting to give an account of 
Lord Kelvin’s views, and Lord Kelvin considers the tides to 
be all-important in this respect. He considers and dismisses 
as comparatively unimportant the agencies alluded to by Mr. 
Chree. ‘ 
The evidence from the mean density of the earth was never 
put forward as conclusive, but only as suggestive. 
I can only account for the remark that I ‘‘might be well 
advised to allow for the possibility that Lord Kelvin’s speculations 
do not possess a monopoly of physical uncertainties,” on the 
hypothesis that Mr. Chree has not read my address carefully, 
or has failed to comprehend the attitude I assumed. I all along 
recognised the ‘‘ physical uncertainties’ on every side, and made 
no claim whatever to replace them by certainties. My whole 
| object was to show that no certain conclusions can be reached 
