498 
NATURE 
[AprIL 14, 1923 



been born and brought up, but to which probably not 
one in a hundred, even among scientific men, has given 
two minutes’ original thought. 
The great clarification of ideas which distinguishes 
modern science, and especially physical science, 
ought not to stop short of this most vital and funda- 
mental problem which so menaces the well-being of 
the community. It is, indeed, a most fascinating 
problem for its own sake. The mathematician would 
enlarge his knowledge of the consequences of a 
mistake in sign in a field where such mistakes are of 
fearful import to whole nations, and the physicist, 
of a perpetual-motion machine fallacy underlying and 
destroying the hopes, not of a half-crazy would-be 
mechanic, but of a half-crazy would-be mechanical 
civilisation. In his well-known book, ‘“ Instincts of 
the Herd,’’ Mr. Trotter has put one obvious point 
inimitably. “It is this survival, so to say, of the 
waggoner upon the foot-plate of an express engine, 
which has made the modern history of nations a 
series of such breathless adventures and hairbreadth 
escapes.” I venture to suggest that the survival 
of the herd-instincts of the waggoner in an express 
age applies as much to those who have built the 
express as to those who try to drive it. 
The British Association naturally suggests itself 
as providing the proper platform for this proposed 
re-examination of the physical basis of our economic 
system, since it has an Economics Section which, no 
doubt, would welcome as eagerly as the public the 
introduction of an element of science into its proceed- 
ings. One needs to be only a casual observer of the 
trend of events to know that the public, thoroughly 
alarmed by the consequences of peace, and fearfully 
awaiting asphyxiation in the next war, would take an 
interest in this question that would rival that of the 
palmy days of Huxley and the Bishops. 
FREDERICK SODDY. 
WE shall all sympathise with Prof. Soddy’s desire 
that our industrial system should give a state of 
society in which the material lot of the people should 
be “‘ vastly improved ”’ by the application of science. 
We should differ from him in various degrees as to 
the extent to which this has been already secured, 
and the means which should be taken to accelerate 
the process. I gave in the article quoted some 
reasons for believing that considerable improvement 
had taken place: it seems, in fact, untrue to say that 
““we are perishing’’ under our present economic 
system. The only country which can be said to 
have come near to “ perishing’’ is Russia, which 
attempted entirely to discard the system and is now, 
after a desperate experience, painfully and slowly 
retracing her steps. The next most seriously dis- 
tressed country in the world is China, which has never 
attained to our modern industrial system. 
By all means enlist the Economics Section of the 
British Association in a discussion of the problem— 
or rather the host of problems—involved. But do not 
antagonise the Section at starting by suggesting that 
it would be a good thing to introduce “ an element 
of science into its proceedings.’’ The Section has been 
proceeding on that assumption for a good many 
years now. 1 Soe 

Tactile Vision of Insects and Arachnida. 
WitH reference to Commander Hilton Young’s 
suggestion noted on p. 409 of Nature for March 24, 
it may possibly be of interest to record the con- 
clusion at which I and my colleagues arrived, when 
engaged, two years ago, in research on the so-called 
NO. 2789, VOL. 111 | 


eyes in insects and arachnida. In all the species 
studied, including the house-fly and red ants among 
the former, the house spider (Tegenavia domestica) 
and many of the Epeire among the latter, we were 
forced to the conclusion that the organs generally 
known as eyes do not act as organs of vision. What. 
their main purpose is, was never certainly determined 
by us; but the many phenomena which were studied 
as evidence of sight could all be reduced to touch 
sensations. For example, to take perhaps the simplest 
illustration, if the hand be slowly advanced towards. 
a fly on a window-pane, the insect, if it be a vigorous 
specimen, will evade the caress. But if the hand. 
be advanced towards the fly when the insect is on 
the opposite side of the glass to the hand, it may 
often be necessary to tap severely in order to disturb 
its wanderings. ” 
Apart from air currents due to the motion of the 
hand, and possibly some convection currents due to 
the heat of the same, it is difficult to afford any. 
other satisfactory explanation of this simple pheno- 
menon, which any one can examine for himself with 
the greatest of ease. J. PAQHiras 
St. Beuno’s College, St. Asaph, 
March 24. 
The Resonance Theory of Hearing. 
THE difficulty expressed by Sir James Barrett in 
Nature of March 24, p. 396, is probably more 
apparent than real. If attention is focussed on the 
relative dimensions of the various parts of the cochlea, 
rather than their actual sizes, I think that the range 
of analysis can be explained. : 
In the short compass of a letter I cannot deal with 
a full consideration of the analytical mechanism of 
the cochlea. A variation in pressure applied to the 
fenestra ovalis, if it is to cause a movement of the 
basilar membrane, must cause movement of the 
liquids in the cochlea. The impedance due to the 
inertia of the liquid is considered by Mr. Wilkinson 
as a ‘‘load”’ on the vibrating strings. In all con- 
siderations of the action of the cochlea the influence 
of the viscosity of the liquid has been overlooked 
(see Philosophical Magazine, 1922, vol. 43, Pp. 349)- 
The friction of the liquid against the walls of the 
cochlea impedes the movement of the liquid so that 
if the diameter of the cochlea were uniform the 
resistance would be proportional to the distance from 
the fenestra ovalis. As the cochlea becomes narrower 
this is a safe assumption. If the highest audible 
note acts on the basilar membrane 5 from the com- 
mencement of the cochlea, the ratio of the impedance 
due to viscosity of this highest note to the lowest 
note might be 35,000 to 5. This is approximately 
the ratio given by Mr. Wilkinson without the pre 
tion of any difference in tension in the fibres of the 
basilar membrane. I do not wish to imply that there 
is no difference in tension, but the greater bulk of 
the spiral ligament may be merely to resist a greater 
strain, and is not necessarily an indication of a greater 
initial tension. 
If one wishes to look at this subject from the point 
of view of resonance, the effect of viscosity can be 
illustrated by narrowing the orifice of an air resonator. 
This lowers the note, just as the viscosity makes the 
note lower for the distal end of the cochlea, but the 
viscosity of a liquid will be much more important 
than the viscosity of a gas. Viscosity, however, is 
only one of the factors concerned in sound analysis. 
H; EE) Rosnaee 
London Hospital Medical College, 
Whitechapel Road, E.1, 
March 26. 

