a ee 
JANUARY 1, 1914 | 
NATURE 
501 
be published shortly in the Verhandlungen der 
deutschen physikalischen Gesellschaft, the relation 
between the wave-length and the positive charge may 
be obtained in a large number of different ways. For 
the present it may suffice to point out that it may be 
derived from a simple consideration of the dimensions 
of the quantities involved. 
The frequency y can only be supposed to depend upon 
the magnitude of the positive and negative charges 
Ne and ne, upon the mass of the moving charge m, 
upon the distance between the charges r, and, if we 
wish to introduce the quanta, upon Planck’s element 
of action, h. As Nne?, m, r, and h must be com- 
bined in such a way that the dimension of the result- 
ing quantity is that of one finds 
(NnML*T-*)eMyLe(ML?T-1)u=T-!, or 
X+Y+U=0, 3X+23+2u=0, and —2x—u=—1, whence 
y=X—I, 2=x—2, and w=1—2x. 
It is interesting to see what assumptions are neces- 
sary to produce an approximate agreement with the 
experimental data if one inserts various values for x. 
If x=0 we find vy =const. - Ls ; the constant being of 
» mr 
the order unity as Einstein pointed out. Assuming 
the characteristic X-rays to be due to the movement 
of a single electron, we must suppose r to be propor- 
tional to 1/N, where N corresponds to the number of 
free positive charges on the nucleus found by Ruther- 
ford and van den Broek. Roughly speaking, this 
would be the case if the repulsive force keeping the 
electrons away from the centre were proportional to 
1/r*, as suggested by Sir Joseph Thomson. If x=3 
find 
teresting, as it does not contain h, i.e. it may be 
p2 
nNe 
const me ms 
we a This formula is in- 
derived from the ordinary laws of mechanics. It also 
reduces to Moseley’s formula if r~ 1/N. 
If x=1 the formula is y=const. If one elec- 
tron is supposed to oscillate, r must again be assumed 
proportional to 1/N to fit the facts. If all n=N 
electrons oscillate, r must be supposed to be constant. 
In this case the formula accounts also for the second 
series of lines which Moseley’s formula fails to do. 
They may be calculated with great exactitude by 
N(N- 1)e* 
hr 
atom which has lost an electron. 
putting v=const. which corresponds to an 
WN 
If we put +=2 we find »y=const. ” as 
h 
33 Which 
is obviously identical with Moseley’s formula, if we 
suppose only one electron to oscillate. The agree- 
ment of Bohr’s constant with experimental data is 
not convincing to my mind in view of the large 
number of arbitrary assumptions in his derivation. 
All the above formule are independent of the choice 
of any special model. They are selected so that the 
expression for y is successively independent of e2, h, 
m, or r. They would seem to prove that Moseley’s 
figures need not be taken to confirm Bohr’s views on 
the constitution of the atom. The only essential 
assumption common to all of them is that N should 
correspond to the place of the element in the periodic 
table approximately as suggested by Rutherford and 
van den Broek, and it would seem therefore that this 
hypothesis only can be said to be supported by Mose- 
ley’s experiments. F. A. LinDemMann. 
Sidmouth, December 28, 1913. 
The Plumage Bill. 
Sir Harry Jounsron’s plea for the Plumage Bill 
in Nature of December 11 will, no doubt, be con- 
sidered an acceptable contribution by those who believe 
they possess the mental altitude to which he was born. 
NO, 2305, VOL. 92] 
I venture, however, to suggest that if he and his 
friends will leave their high mental estate and descend 
to the plain facts that business men must consider in 
this lower sphere, he will be obliged to admit that, . 
like the trade, the educated naturalist has much to 
‘learn. 
He admits the glaring defects of the Plumage Bill, 
but welcomes the measure as better than none. If he 
and his friends are able to conceive nothing more 
than an admittedly bad Bill, that will have no effect 
on bird-life, he is scarcely justified in his abuse of 
those who are willing, and trying to solve the problem 
of saving both the birds and the trade. 
His presumption that none but an _ educated 
naturalist knows how the skins are procured, or the 
approximate habitat of the birds, or their right name 
in English or Latin, does not raise the controversy 
to any higher plane. Was he not an educated 
naturalist who bestowed the name of Apoda upon one 
of the species of paradise bird, believing it be born 
without feet? In 1908, before the Select Committee 
of the House of Lords, did not Sir Harry Johnston’s 
friend, Mr. Buckland, declare that the destruction of 
birds of paradise was at that time so rapid that the 
species could not last more than two or three years? 
I see little more in the article which Sir Harry John- 
ston quotes from The Times of Ceylon than a con- 
firmation of the trade statements that the birds of 
paradise are collected under a system regulating their 
killing, and that the family is in no danger of exter- 
mination. The article shows the valuable commercial 
asset that Dutch New Guinea possesses, and that its 
Government is taking full advantage of it under an 
adequate system of protection. 
Mr. Buckland will be surprised to hear that there 
are so many birds left that this year’s production is 
likely to result in a trade of about 200,000 skins, but 
he will perhaps be pleased to know that I do not 
believe it. Both gentlemen should be more concerned 
in those beautiful specimens said to fetch as much as 
4ol. or more. These are undoubtedly the rare and 
disappearing species that have no trade interest, but 
are eagerly sought after for scientific purposes. Even 
though they be the last survivors of their kind and 
need some stronger measures than any existing, in 
order to prevent their utter extermination, supporters 
of the Plumage Bill have conceived nothing more 
than a measure that permits their import until none 
are left, and also prohibits the import of species that 
are plentiful. L. JosEPH. 
Plumage Committee of the Textile Trade Section 
of the London Chamber of Commerce, 
Oxford Court, Cannon Street, London, E.C. 
December 17. 
My reply to Mr. Joseph is as follows :— 
I only admit the defects of the proposed Plumage 
Bill in that it is not sufficiently drastic. But I am 
always one of those who think half a loaf is better 
than no bread, and that great restrictive or revolu- 
tionary measures of legislation are seldom carried all 
at once. I should like to see British officers and 
tourists restrained from destroying the wild mam- 
malian fauna throughout the British Dominions; 
meantime I welcome sporting licences, close times— 
any measure which may tend to prolong the existence 
of interesting wild beasts. So although I should 
prefer a more complete exclusion from this country 
of the plumage of rare and remarkable wild birds, I 
am prepared to accept Mr. Hobhouse’s Bill as an 
instalment of protective legislation. 
I continue to assert the utter ignorance of their trade 
and of the sources and correct nomenclature of their 
goods which characterise the firms trading the skins 
and plumes of wild birds. The fact that Linnaeus and 
