ae 
Pye oe 
Sept. 18, 1873] 
NATURE 
399 
a 
—one from whom the mathematicians of the future may 
* derive valuable and fertile methods. 
For the advance of the exact sciences depends upon 
the discovery and development of appropriate and exact 
ideas, by means of which we may form a mental re- 
presentation of the facts, sufficiently general, on the one 
hand, to stand for any particular case, and sufficiently 
exact, on the other, to warrant the deductions we may 
draw from them by the application of mathematical 
reasoning. 
From the straight line of Euclid to the lines of force of 
Faraday this has been the character of the ideas by 
which science has been advanced, and by the free use 
of dynamical as well as geometrical ideas we may hope for 
a further advance. The use of mathematical calcula- 
tions is to compare the results of the application of 
these ideas with our measurements of the quantities con- 
cerned in our experiments. Electrical science is now in the 
stage in which such measurements and calculations are 
of the greatest importance. 
We are probably ignorant even of the name of the 
science which will be developed out of the materials we 
are now collecting, when the great philosopher next after 
Faraday makes his appearance. 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions expressed 
by his correspondents. No notice is taken of anonymous 
communications. | é 
Tyndall and Tait 
I HAVE hitherto refrained from intruding upon your space with 
reference to this deplorable Forbes’ controversy, but now that the 
occasion has come when a brief deliverance on my part seems 
called for, I trust to your courtesy, if not to your justice, to allow 
me room for it, 
In the first place I would ask permission to inform such of 
your readers as may feel an interest in the subject, that if they 
wish to form a correct opinion of the tone and logic of my re- 
joinder to Principal Forbes and his biographers, they will consult 
the rejoinder itself, as published by Longmans, and not the ex- 
tracts and inferences of Professor Tait. 
They will thus learn, among other things, that what Professor 
Tait calls “‘ plausible ,” is simply unanswerable. 
With regard to the taking up of the various points in Principal 
Forbes’s reply, item by item, that may be done some day should 
I deem it a worthy occupation. In my rejoinder I conyerged at- 
tention on the two points which Principal Forbes himself consi- 
dered the really serious ones, and having broken the neck of the 
argument in both these cases I cared little about prolonging the 
‘controversy. Nevertheless if circumstances show it to be neces- 
sary it may be prolonged. 
Professor Tait invariably writes on the hypothesis that what 
is not contradicted cannot be contradicted, and must therefore 
be accepted as true—a natural, if not inevitable, assumption on 
his part. For example, Forbes’s argument regarding the cre- 
vasses of Rendu was left unanswered by me, hence the conclu- 
sion that it was unanswerable, That argument, however, is now 
in shreds, as it might have been, had I so willed, any time during 
the last dozen years. Again, Principal Forbes makes an assere 
‘tion regarding his tutelage of Agassiz ; the assertion is left uncon- 
tradicted ; it must therefore be accepted as true, and I am unjust 
‘because I do not so accept it. Thirteen years ago, however, I was 
in possession of a diametrically opposite assertion from M. 
Agassiz. Quite as distinctly, though not so specifically, he 
writes thus within the present year. ‘* When Forbes came to 
visit me upon the glacier of the Aar, he knew not only every- 
thing that I had done, but also my plans for the future. When 
he left he positively declined to express any opinion concerning 
glacier phenomena, under the plea that he only came to gratify 
‘his curiosity, and had no intention of following up the subject, 
-as he had no desire to be involved in the controversy then raging 
regarding the former extension of glaciers.* When he showed his 
hand I did not enter into a protracted discussion, but simply 
made a statement of facts and let the matter rest. sh eneara 
When I look,” adds M. Agassiz, “on the whole transaction it 
seems incredible. There is in it no vestige either of the gentle- 
man or the honest investigator,” 
With statements of this character confronting the assertions 
of Principal Forbes, the proper course for me was to ignore as- 
sertions on both sides, and to confine myself to demonstrable 
facts. This I accordingly did. 
With regard to Mr. Tait’s criticism of my ‘‘ popular ” writings 
it has, of course, nothing to do with his defence of F orbes, but is 
the product of mere ignoble spite. Heasks me to reply to him not 
according to the letter, but according to the spirit of his attack, 
If I might use the expression I would say, ‘‘ God forbid!” for 
how could I dojso without lowering myself to some extent 
to his level. The antecedents of Mr. Tait with reference 
to me are pretty well known. When I sought to raise 
from the dust a meritorious man whose name is now a house- 
hold word in science, who has been elected by acclamation 
a member of the French Academy, and who has received the 
crowning honour of the Royal Society—when I sought to place 
Dr. Mayer in the position which he now holds, and from which 
no detraction can remove him, it was Mr. Tait who, in Good 
Words, charged me with misleading the public; who followed 
up his attack in the ‘‘ Philosophical Magazine,” and who when 
publicly hoisted by his own petard, retired to void his venom 
against me in the anonymous pages of the ‘‘ North British Re- 
view.” It is this man whose blunders and whose injustice have 
been so often reduced to nakedness, without ever once showing 
that he possessed the manhood to acknowledge a committed 
wrong, who now puts himself forward as the corrector of my 
errors and the definer of my scientific position. That position 
is happily not dependent upon him, and his opinion regarding it, 
is to me, as it will be to most others, a trifle light as air. But 
gtaver considerations than mere personal ones here arise. 
Might I venture, Mr. Editor, to express a doubt as to the 
wisdom of permitting discussions of this kind to appear in your 
invaluable journal. Having opened your columns to attack you 
are, of course, in duty bound to open them to reply, but if I 
might venture a suggestion, you would wisely use your un- 
doubted editorial rights, andconsult the interests of science, by 
putting a stop to proceedings which dishonour it. Anillustrious 
person writes to me thus :—‘‘I have just read Professor Tait’s 
letters in NATURE, and feel a recurrence of that pain which 
similar communications once inflicted on myself—pain felt, not 
on my own account, for I knew that the attacks would no more 
sully me in the opinion of those whom I loved and respected, 
than they did in my own opinion; but pain for the wounded 
honour of science and the outraged dignity of scientific contro- 
versy.” Joun TyNpDALL 
Atheneum Club, Sept. 16 
[We deeply sympathise with Professor Tyndall’s remarks on 
the injury done to scientific controversy by the introduction 
into it of personalities, and we should have made his own letter 
square with his canon if his reference to our duty in this matter, 
and his insinuation of injustice did not take the matter out of 
our hands. Prof. Tyndall forgets (1) that Prof. Tait’s letter is 
an answer to a pamphlet by Dr. Tyndall, and that space was 
asked for it as such; and not an atlack in the sense 
in which Prof. Tyndall uses the word ; (2), that if the Editor 
were to assume the power and responsibility that — Prof. 
Tyndall suggests, NaTURE might easily fall from the position of 
absolute justice and impartiality in all scientific matters which it 
now occupies and become the mere mouthpiece of a clique. 
What the Editor can do and has endeavoured to do in this 
case, is to guard the reputations of men of Science against the 
attacks of men of straw, and to see that no personalities are 
used ; and it is under strong protest that he allows to pass in 
Prof. Tyndall’s letter, for the reasons already stated, p -rsonalities, 
the equivalents of which, the Editor, in the exercis- of his “* un- 
doubted editorial rights,” struck out of Prof. Tait’s communica- 
tion. —Ep, NATURE. ] 
* This tallies with Forbes’s own account (Travels, page 38). “ Far from 
being ready to admit, as my sanguine companions wished me to do in 184r, 
that the theory of glaciers was complete, and the cause of their motion cer- 
tain, after patiently hearing all they had to say, and reserving my opinion, 
&c,” This reservation of opinion is probably the reticence referred to by 
Agassiz. 
