JANUARY 25, 1917] 
tant, and merely announcing the results of researches 
which are too restricted or evidently unfruitful. 
These publications must be, as I have said, inter- 
national in so far as collaboration and content are 
concerned. The collaboration of neutral countries 
ought to be desired and sought, and, in the future, 
even German collaboration might be accepted, if the 
authors should wish to become acquainted with, and 
appreciated by, the scientific men of the nations of 
the Entente as well as of their own group of nations. 
Thus these publications would have the effect of taking 
away from Germany that monopoly of science at 
which it has arrived during fairly recent years with 
so much success. We would thus show it the value 
of the scientific contributions of other nations, and 
this would lower its immoderate and ridiculous pride 
which has been one of the causes of the present war. 
This, moreover, would be without taking the least 
“hostile action against German science. 
It may perhaps be permitted to the writer of this 
letter to recall how, before the war, amicable pro- 
posals were made to him from Germany—both by con- 
tributors and by other authorised representatives of 
German science—that, in the international scientific 
review which he has the honour of editing, the supple- 
ment which contains French translations of all articles 
written in German, English, or Italian, and published 
in the text in those languages, should be replaced by 
a supplement containing German translations 
of the English, French, and Italian articles. Evi- 
dently this international review seemed to them, con- 
ducted as it was, and is, by non-Germans, a kind of 
menace to their scientific hegemony, which they were 
trying to consolidate more and more. Thus, they tried 
to arrange that it should at least have a German air 
and colour to take away its dangerous look of a 
standard of revolt against German hegemony. 
The hour has come to create and develop as much 
as possible in the principal branches of science, under 
the zgis and direction of the Entente, international 
scientific publications and reviews which should be 
fitted to destroy finally a monopoly which, if it foments 
sentiments contrary to the establishment of inter- 
national relations founded on mutual esteem, consti- 
tutes a very grave danger for the progress of science. 
These suggested periodicals will thus contribute to 
re-establish on bases of independence and equality 
that equilibrium of nations which will be the greatest 
guarantee of a peace that is just, long, and to the 
benefit both of our present Allies and of our present 
enemies, EuGENIo RiGNANO 
(Editor of Scientia). 
Stability in Flight. 
In this paper on ‘‘ Forced Oscillations of a Disturbed 
Aeroplane” (Aeronautical Journal, October-December, 
1916), Dr. Brodetsky shows, on theoretical grounds, 
that among the chief conditions of safety and stability 
in windy weather are: (1) a small tail, or small ratio 
of tail/main-plane, and (2) comparatively small wings, 
or small ratio of total area/load. In. a former paper 
by Prof. Bryan and Dr. Brodetsky (ibid., April—June), 
the fact that long tails are on the whole disadvan~ 
tageousis demonstrated. All these conclusions seem to 
agree well with what we may very easily observe in 
birds. Those birds the flight of which is what one 
might call skilful, or agile—that is to say, those which 
can rapidly dodge and steer, or which do not mind 
flying in high and shifty winds—are (I should say) all 
characterised on the whole by small tails and com- 
paratively small and narrow wings. These features 
are conspicuous in many of our shore birds, sand- 
pipers and the like, and the birds are equally con- 
NO. 2465, VOL. 98] 
NATURE 
409 
spicuous for their extraordinary stability, whether 
against wind or in their own sudden and acute 
changes of course. Seagulls, solan-geese, albatrosses, 
and swallows share, more or less, in the same struc- 
tural characteristics. Powerful or long-continued 
flight is evidently quite a different thing. Thus the 
pigeon is a splendid flyer for mere distance, and even 
for speed; but it goes straight ahead, and its large 
‘tail and large rounded wings give it only a moderate 
“stability.” In like manner a multitude of little 
birds, robins and the like, which we are apt to think 
of as bad or unskilful flyers, turn out to be very good 
flyers indeed upon their migratory journeys, when all 
they have to do is to pursue an even course in high 
and relatively calm regions of the atmosphere, and 
also (as we may suppose) in carefully selected weather. 
On the other hand, the really long-tailed birds, such 
as the magpie and some of the foreign jays, trogons, 
etc., are all very poor flyers, and are for the most 
part birds of the sheltered woodlands. 
Another case in point is that of the hawks and 
falcons. The broad-winged hawks, such as the buz- 
zards and the kestrel (the latter with its long tail; 
which it uses effectively for another purpose), were 
all despised of the falconer; the kinds with long and 
narrow wings, like the merlin and the peregrine, were 
the ones he prized. 
I am curious to know what experts think of another 
matter, namely, the long, outstretched legs of such 
birds as the stork and heron. One used to be told 
that these serve as a rudder, making up for the 
insignificant size of the tail, but this explanation seems 
far from satisfactory. I imagine the long legs act 
as a very useful counterpoise to the long neck and 
bill; that they help to adjust the position, longitudin- 
ally, of the centre of gravity (which Borelli says ought 
to be directly under the articulation of the wings); 
and further, that the lengthened axis so formed, from 
beak to outstretched toes, may play the part of a sort 
of balancing pole, and contribute very materially to 
the creature’s longitudinal stability. In any case, it is 
certain that these long-legsed birds are extraordinarily 
graceful flyers, remarkable for their perfect balance 
and quiet, easy motions. 
D’Arcy W. THompson. 
An Explosion Effect. 
A RECENT explosion has, like all other similar occur- 
rences been productive of many curious results, but 
one that I have noted seems worth special mention. 
There is a row of large houses in an exposed situation, 
directly facing the centre of explosion, but about three 
miles from it, and in front of one of these houses is a 
medium-sized pond. In this row most of the houses 
have escaped, only two or three broken or cracked 
windows being noticeable among the lot, with one 
exception. That exception is the house facing the 
pond, which, so far as glass is concerned, is wrecked. 
From appearances it might have been played over with 
a machine-gun. One house near, and also facing the 
pond, has only one window damaged, but in this case 
the sashes are destroyed as well as the glass. It 
appears that nearly every window situated on a line 
crossing the pond from the explosion centre has 
suffered extra violence. I believe similar results have 
been noted before over water, but this seems a very 
striking instance. I should, perhaps, add that the glass 
destroyed was of indifferent crown quality, whereas 
the other houses appear all to have thin plate-glass ; 
but much crown glass has escaped damage in other 
positions, where heavy plate has gone to pieces, so I 
think it clear that the pond, and not the quality’ of 
the glass, was the contributory cause. ‘ 
C. Wetsorne Piper. 
