606 
conditions of existence.” There are some rather 
more pleasing chapters on truth and on the 
“fourth dimensional consciousness,” but one 
would have preferred these speculations without 
their quasi-scientific sprinkling. 
Continuity. The Presidential Address to the 
British Association, Birmingham, MCMXIII. 
By Sir Oliver Lodge. Printed in full and 
supplemented by explanatory Notes. Pp. 118. 
(London: J. M. Dent and Sons, Ltd.) Price 
Is. net. 
Ir will be remembered that Sir Oliver Lodge’s 
presidential address to the British Association was 
printed in full in the issue of Nature for 
September 11 last (vol. xcii., p. 33). Its republica- 
tion with twenty-four pages of explanatory notes 
should ensure renewed attention to the important 
subjects with which it dealt. 
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.] 
Aristotle’s Physics. 
I am unable to find the passage in his works, but I 
think it was Prof. Ostwald who pointed out that while 
Aristotle was much more impressed with the retard- 
ing effect on the velocity of the mass of the medium 
through which the falling mass fell, than with the 
laws of “free fall,’ Galileo ignored friction, and dis- 
covered the law of fall ina vacuum. Neither was 
right; but air at atmospheric pressure has a very 
small effect on a dense mass falling, and hence Galileo 
was able to establish his law. Had Aristotle pursued 
his line of thought, he might, with adequate experi- 
mental appliances (which he had not got) have dis- 
covered Stokes’s law. 
This forms a very good example of the necessary 
restrictions in all scientific reasoning. In all events 
the factors are too numerous to permit of absolute 
coincidence between theory and experiment; the suc- 
cessful discoverer is he who takes care to eliminate 
the less important factors; it is he who arrives at a 
law, which, though not exact in correspondence with 
fact, still enables progress to be made. Further pro- 
gress ensues, when account is taken of each disturb- 
ing factor, one by one; the initial simple law becomes 
more complicated, but a nearer approximation to 
truth is arrived at. WitiiAM Ramsay. 
19 Chester Terrace, Regent's Park, N.W. 
January 23. 
Capt. HarpcastLe’s authentic quotations from Aris- 
totle are most interesting. May I, as a teacher 
emphasise the fact that ‘‘terminal velocity” is the 
best instance of Newton’s first law of motion in actual 
operation—an instance strangely neglected by elemen- 
tary exponents. On anything moving at constant 
speed in a straight line (like a passenger in a railway 
train) the resultant force acting must be zero, and, so 
far from ‘inertia being eliminated” from such a 
body, its progress is due wholly and solely to its own 
inertia. Non-Newtonian mechanics need not be re- 
ferred to in treating so rudimentary a matter. 
Ouiver Lopce. 
Mariemont, Edgbaston, January 24. 
NO. 2309, VOL. 92] 
NATURE 
[JANUARY 29, 1914 
The Eugenics Education Society. 
WILL you allow me, throughyyour columns, to point 
out another aspect of the present methods of popu- | 
larising ‘‘eugenics”? I had recently occasion to 
criticise this popularisation, and especially the methods 
of the Eugenics Education Society. I then used the 
following words :—Sir Francis Galton was in the 
problems of race an optimist—a_ splendid ae 
but even he in the last few months of his life saw 
that the popular movement he had startéd was likely 
to outgrow its knowledge, and feared ¢ghat more evil 
than good might result from it’? (The Times, October 
tae tO3) 
“In as present number of the organ of the Eugenics 
Education Society there is some criticism of the words 
used by me. It starts as follows :—-We would, if 
possible, avoid all controversy with one who has done 
so much for our science, and who was, moreover, so 
highly trusted by its founder, Sir Francis Galton, as 
is evidenced by his will. One sentence, however, 
cannot be passed over in complete silence, namely, the 
following : ‘ But even he (Sir F. Galton) in the last 
years of his life saw that the popular movement, &c.’”” 
The italics are mine, and these words are followed 
by quotations from the letters Sir Francis wrote in 
1gog, and one from October, 1910. The controversial 
methods which can change ‘‘last months” to ‘last 
years,’ and then cite letters of 1909, are characteristic 
of that looseness of procedure which must eventually 
be fatal to any popular movement run by this society. 
It suffices to say that on my last visit to Sir Francis 
Galton at Haslemere at the end of December, 1910, 
he expressed distrust of the lines on which the society 
was being run, that he was then in doubt as to 
whether he would not do better to resign his honorary 
presidency, and that I personally declined to influence 
his judgment in any way by discussing the subject, 
because he was as able then as when he was fifteen 
years younger to decide for himself. 
When my ‘Life of Sir Francis Galton” is pub- 
lished his letters will show the exact field of work 
he proposed for the society and his appreciation of 
the dangers that might arise from its action. My 
only excuse, sir, for troubling you in this matter is 
that the organ of the Eugenics Education Society is a 
quarterly, and I have no other effective means except 
through the courtesy of your columns to correct a 
wholly erroneous statement, which the editor of that 
society’s journal has put into my mouth. 
Kart Prarson. 
Galton Laboratory, University of London, 
January 23. 
Some Hahitats of a Marine Amoeba. 
In a letter to Nature (No. 2300, vol. xcii.) I de- 
scribed a common habitat of a marine Amoeba, and 
in view of the subsequent discussion of this matter 
in letters to Nature it will be of interest to record 
some further observations bearing on that discussion. 
In the letter to Nature mentioned above it was 
shown that a marine Amoeba, which agreed in many 
of its characters with Amoeba crystalligera of Gruber, 
could be fairly constantly obtained from sponges of the 
genus Sycon, by squeezing out the contents of the gas- 
tral cavities of these animals. At the same time it was 
stated that this habitat of the Amcebz is not likely 
to be an exclusive one. When, therefore, Prof. Dendy 
suggested in Nature (No. 2301) in the following week 
that these Amcebe might be sponge germ-cells, or 
even metamorphosed collar-cells, I at once began a 
search for the Amoebze in other situations. This. 
search was successful; Amcoebez in all respects similar 
to those obtained from the sponges were found in 
