82 
NATURE 
[JANUARY 20, 1923, 

I am obliged to Dr. Harrison for remarking on 
the mistake in my letter in NATURE of December 9 
where in one place ‘“‘ Aphides ’’ was written instead 
of “ Coccide.’’ The specific name proletella, placed 
under the outline sketch in Fig. i a, was given on 
the authority of a well-known entomologist to whom 
specimens were sent for identification. Dr. Harrison 
would name this brassicz. 
With regard to the number of genera and species 
to which he refers, the present tendency seems to 
be to multiply both unnecessarily. Among the 
various Aleyrodids which I examined there appeared 
to be considerable variation, and it was possible to 
collect from the same plant specimens differing in 
size from large to small through many gradations 
and having wing spots either well marked or nearly 
evanescent. 
The difference between “ species ’’.and ‘‘ variety ”’ 
is one of degree, but specific difference may be claimed 
for races which have so diverged that a fertile mixed 
race cannot be produced from them. Whether this 
condition is satisfied in any particular case can only 
be determined by rather laborious trials, but in 
the absence of evidence of this kind it would be more 
correct, and certainly more convenient, while noting 
small differences (which may be constant in certain 
circumstances and localities) to treat them as 
varieties. “ A. MALLOcK. 
9 Baring Crescent, Exeter, 
December 21. 

Science and Armaments. 
I DEsIRE to direct the attention of readers of 
Nature to a matter which I think to be of importance. 
During the war of 1914-18 a great number of scientific 
men, other than those in the medical service, were 
engaged on work which was devoted entirely to 
military ends. 
Since the armistice there has been some tendency, 
not unnatural perhaps, to confuse this war work with 
other researches carried out directly in the service of 
science. In the Science Library, South Kensington, 
cheek by jowl with works on atomic theories or 
relativity, are found such books as one on the organisa- 
tion of the Army Signal Service, and another on 
poison gas warfare which adopts most successfully 
the language of a scientific text-book. In the publica- 
tions of certain learned societies, nominally concerned 
with purely scientific aims, are found descriptions of 
instruments and investigations of almost purely 
military interest. The collection of war material at 
the Crystal Palace is shortly to displace the priceless 
collection of historical apparatus and instruments 
from the Western Galleries of the Science Museum ; 
the instruments are to go into storage, in a place 
where they will be inaccessible to the general public, 
for an indefinite period. 
The lamentable implication seems to be that the 
development of armaments now holds a recognised 
place as one of the worthiest aims of science, but that 
is a doctrine which, I trust, is still very much open to 
question. It is more probable that we simply lack 
good taste and a proper appreciation of relative values. 
I venture to suggest that science would be best 
served by keeping these things separate. If neces- 
sary, let the Government extend a military museum 
to house such of the material from the War Museum 
as possesses real interest from the military point of 
view ; it should not be allowed to displace a single 
instrument from the historical collections. Let us 
also refrain from filling our library shelves with 
matter of the kind previously indicated. So may the 
temple of science be kept free from echoes of human 
quarrels. 
NO. 2777, VOL. 111 | 


The example of the British expedition sent, in spite 
of the war, to test the Einstein effect has often been 
quoted as an outstanding example of the wonderfully 
dispassionate internationalism of science, but it 
scarcely bears comparison with the events of a hundred 
years ago when Davy, taking Faraday as his assistant, 
travelled to Paris to lecture during the height of the 
Napoleonic wars. We have gone far since those 
days—lIn which direction ? L. C. Martin. 
Imperial College of Science, South Kensington. 

Waterspouts. 
Wir reference to the letter from Dr. Hale Car- 
penter (NATURE, September 23, p. 414) describing an 
interesting waterspout seen over Lake Victoria, a 
letter has been received in the Meteorological Office 
from Mr. H. E. Wood, of the Union Observatory, 
Johannesburg, describing the development of a cloud 
pendant seen by him on the afternoon of November 
19, 1922. The following extract from Mr. Wood’s 
letter describes the occurrence : 
“ The day was a particularly calm one, the morning 
was hot with a fairly clear sky, but early in the after- 
noon there were many cumulo-nimbus clouds in the 
sky. I noticed particularly the uniformity in the 
base-level of all the clouds. Just about 3 p.m. I 
noticed a little pendent cone under one of these 
clouds and, having seen a waterspout here once before 
(in 1910) thought this might become one and decided 
to watch it. The waterspout developed rapidly and 
I got Mrs. Wood to make a series of drawings of it. 
Unfortunately the waterspout was rather too far 
away for photography—it would have been very 
small taken with an ordinary camera and I had no 
telephotographic lens available. The interesting 
feature of the waterspout seemed to me to be the 
detail of the earth-end (as shown in Fig. I reproduced 
a 
’ 
f =F 
J 
f por 
ral 
. a 
= Soe 
é pieces —————— 
Fic. 1. 
from a sketch made at 3.15 P.M.) : there was a well- 
marked ‘“‘ core’ surrounded by a less dense sheath. 
It did not rain in the vicinity of this spout until some 
time afterward ; so that the lower part would probably 
consist of dust. Later we saw a series of waterspouts 
in the same vicinity. We estimated (when this parti- 
cular cloud became an active thunderstorm) that the 
distance of the waterspouts was about 8 miles and 
hence that the length of the column or height of the 
cloud base was about 3700 feet.”’ 
The phenomenon noted by Mr. Wood is very similar 
to that noted by Dr. Hale Carpenter, except that in 
the present case the part shown in the sketch is 
probably due mainly to dust raised by the whirl. It 
is possible, however, that the greater density of the 
central core is due to condensation of water vapour. 
D. Brunt. 
Meteorological Office, Air Ministry, 
December 23. 

I stoop watching the effects of an ordinary small 
whirlwind when a Swahili volunteered the information 
that similar phenomena were at times to be seen 
over the sea, but that, in those cases, what one saw 
was God (Muungu) drawing a whale (nyamgum) aloft. 

