686 
be abolished, no matter if the most exquisite birds 
become extinct. 
It is known that many trades have suffered 
severely from the advent of the motor-car. 
Whip-makers have scarcely anything to do. Harness- 
makers have also suffered, yet these trades could 
scarcely demand that motors should not be used 
because such might suffer thereby. And as the world 
becomes more thoughtful and humane, surely if birds 
are to be safe the plumassiers must go to the wall, 
and no great harm. There are other callings in 
which they must by degrees embark. 
It is very strange that men do not more definitely 
show how very much they dislike seeing ospreys and 
humming-birds in women’s hair or headgear. Men 
who are most feeling and know all about it, and 
keenly detest the cruelty that these ornaments involve, 
will sit by women at dinners and operas and not 
show in the slightest degree what they feel about 
these barbarous ornaments. After all, women only 
adorn themselves to please men, and if these had 
the courage to show how intensely they disliked, and 
were distressed, by these things, they would decidedly 
not be worn. To their intimates they could say, 
“How much more charming you would look with 
anything on your head or hat than that.” 
Of course, there is no denying the fact that woman 
is the sinner, and it seems very sad and shocking 
that all the trouble and misery brought upon birds 
with beautiful plumage is owing to the ignorance 
or cruelty of woman—cherchez la femme. Yes, alas! 
woman—and woman alone—is the sinner. She will 
not listen to the voice of her sisters who do know, 
and who so gladly would, and could, put her in the 
right way of looking at the matter. As she adorns 
herself chiefly to please men, well, let them educate 
her, with scorn and strong words if her vanity or 
stupidity leave her cold to information kindly given. 
There is no supply without demand. This holds 
good of every commodity; and let the demand once 
cease, and all the endeavours of the kind-hearted 
lovers of the beautiful to preserve birds now so ruth- 
lessly destroyed for no purpose but the adornment 
of vain and stupid women will be needless. 
There is such an abundance of lovely ornaments 
to be had. Natural or artificial flowers, exquisite 
ribbons, laces, &c., and if there must be feathers, 
then take some which require no cruelty to procure, 
and which the deft fingers of most clever workers 
can dye and trim into things of weird beauty, almost 
as pretty as the real thing, for glint and twist can 
be added to ducks’ and fowls’ feathers enough to 
satisfy a savage. These would not only save the 
birds, but their feathers, being no longer required, 
would come into ever-increasing demand, and give 
work to thousands of women who are always com- 
plaining that there is nothing much left for them 
to do. This makes so many of them force themselves 
into positions which males could occupy. Every 
woman who takes a position a man could fill prevents 
one man marrying. This is an aspect of the case 
seldom considered by women, and would be well for 
them to ponder on. One is glad of any argument to 
induce women to think and to act in such a way that 
the horrible cruelties associated with their feathered 
heads may in time be a thing of the past. There is 
no doubt if they knew the shocking cruelties per- 
petrated to obtain such an unsuitable adornment to 
any kind-hearted woman’s head, they would certainly 
not wish the real ospreys and humming-birds’ 
feathers to be procured for them. 
Of course, imitation feathers would be cheap—to 
some women an unpardonable fault. Well, when the 
adornment must be expensive, there are jewels and 
laces. \O aap 
NO. 2312, VOL. 92] 
NATURE 
[FEBRUARY 19, 1914 
Specific Heats and the Periodic Law—An Analogy from 
Sound. we 
I am much interested in Dr. H. Lewkowitsch’s 
letter on specific heats and the periodic law, which 
appeared in Nature of February 12. His suggestion, 
based on Guldberg and Wage’s “‘mass law,” of a re- 
conciliation between Sir James Dewar’s recent low- 
temperature experiments and Dulong and Péetit’s 
earlier experiments on specific heats, seems to me 
most valuable. ; ‘ : 
I am well aware that analogies are apt to be 
dangerous, especially when pushed very far. Never- 
theless, I am proposing to put forward the analogy 
from acoustics which may interest some of your 
readers. : 
The experiments on which my analogy depends are 
performed on an ordinary pianoforte, and as they may 
be repeated by anyone, I will state the directions 
thus :—Very gently strike a high note (say C in alt) 
with ‘“‘loud’’ pedal down and the finger soon removed ; 
change to soft pedal and notice how long the note is 
audible as you sit at the piano. Repeat in all par- 
ticulars with a lower note (say C, two or three octaves 
below). It will be found that the lower note persists — 
very much longer than does the higher note. Next 
repeat everything in the same way, but strike power- 
fully instead of gently. Notice the time during which 
each loud note remains loud (or audible to a friend 
in the next room). It will be found that there is 
very little difference in the duration of the two loud 
notes. yet : 
I think the analogy to be deduced is fairly obvious,” 
but I will state it nevertheless. - oe bd oa 
Very soft notes arise from wires when vibrating 
with small amplitudes; these wires correspond to 
atoms at very low temperatures, for atoms under such 
conditions vibrate also with small amplitudes. ; 
On the piano a definite amount of damping (pro- 
duced by pedal action) curtails the amplitudes of the 
compared vibrating wires in a ratio which approxi- 
mately is inversely proportional to their respective 
masses—i.e. equal damping (equal resistance to 
motion) has the smaller effect on the more massive — 
wire. The results of Sir James Dewar’s experiments 
at low temperatures are echoed pianissimo by these 
vibrating wires. j 
Louder notes correspond to higher temperatures; 
the amplitudes both of wires and of atoms are wider. 
In these circumstances of higher excitement, it is 
found on the piano that about the same amount of 
energy is wanted to reduce equally the loudness of 
light and heavy wires, while in the calorimeter it was 
shown by Dulong and Petit that about the same 
amount of energy is degraded in reducing equally the 
temperatures of light and heavy atoms. : 
: REGINALD G. DuRRANT. 
The College, Marlborough, Wilts. 
X-Rays and Metallic Crystals. 
In Nature (August 14, 1913), and later in the 
Philosophical Magazine (October, 1913), Keene gave 
an account of some inieresting experiments on the 
transmission of X-rays through rolled metal sheets. 
In connection with his investigation it may be of 
interest to record some results we have obtained in 
recent work on metallic crystals. 
Some preliminary experiments were carried out with 
annealed specimens. A lump of copper, for instance, 
was cut in two, and one of the pieces heated up to a 
high temperature and then allowed to cool gradually, . 
whilst the other piece was left untreated. Beams of 
X-rays were allowed to fall at almost grazing inci- 
dence on the two newly cut surfaces, and the reflected 
