56 NAT ERE 
[Maxcn 28, 1912 
a concise description of each species. This in- 
cludes the local name or names (if any); its distri- 
bution in Australia; its status—whether stationary 
or migratory, comparative abundance, &c.; the 
kind of country it frequents; a short description 
of its size and plumage, and a few words as to its 
song or other notes, and its food. All the species 
are illustrated, and in the majority of cases are 
figured in colours as well as in black and white. 
The illustrations are, with few exceptions, from 
specimens in the National Museum. 
In addition to this useful and necessary, but 
somewhat dry, portion of the handbook, about a 
third of the little volume is occupied by a most 
interesting lecture on the Australian avifauna. 
Thus the book appeals to a much wider class of 
naturalists than that for which it has been mainly 
written. For the ornithologists of other countries 
will find in it an excellent introduction to, and a 
valuable account of, the birds of a very interest- 
ing part of the world. Mr. Tate in his introduc- 
tion alludes to the growth of a generation trained 
to look upon the characteristic beauties of Aus- 
tralia with an appreciation almost unknown to 
their pioneering fathers and mothers, and he 
combats the popular belief that their birds are 
songless. An index to the coloured plates and a 
general index make reference to any particular 
bird easy. 
Unity in Nature: an Analogy between Music and 
linfe) By. \C. 1B. Stromeyer 9 Pp) 3-580; 
(London and Manchester: Sherratt and 
Hughes, 1911.) Price 12s. 6d. net. 
Tuis is a readable discourse on things in general, 
from physics and astronomy to ethics and politics. 
As the title indicates, the author expounds cer- 
tain musical analogies, such as the relation be- 
tween intervals in the octave and distances in the 
solar system; but, after the first few sections, the 
matter of the book becomes more general. There 
is a good deal of amusingly-put speculation about 
the kind of world that a “flatland”’ of two dimen- 
sions would be (as sketched by Mr. Hinton), and 
this, of course, leads to fourth-dimensional space 
and what might happen there. Then, after a 
chapter on sexual ethics in which a more or less 
Schopenhauerian doctrine is taught—with much 
apt illustration, historical and geographical—we 
come to the female suffrage question, on which 
the author has vigorous opinions. If women get 
the vote, “there is every probability that female 
Members of Parliament would scon be elected; 
these would decide to elect female Prime Minis- 
ters, and as Parliament claims to be omnipotent, 
there is the prospect of having autocratic female 
rulers” (p. 507). Also on the disproportionate 
number of lawyers in Parliament Mr. Stromeyer 
has some cutting and probably justified remarks; 
and on education he enters a wise protest against 
too much classicism. The punctuation of the 
book leaves something to be desired, and on 
p. 104 “bromide” appears several times when 
“bromine” is meant; but these are small details. 
The author shows wide culture and has a pleasant 
style. 
NO. 22135) VOr. (S9)| 
LEEDS TORE ED lMORs 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents. Neither 
can. he undertake to return, or to correspond with 
the writers of, rejected manuscripts intended for 
this or any other part of Nature. No notice is 
taken of anonymous communications.] 
Prof. Bergson and the Eye of Pecten. 
I rrinp that Prof. Bergson in his Philosophies has 
been making use of a comparison between the eye of 
Pecten, the scallop, and the vertebrate eye. This 
comparison is used as the basis of some far-reaching 
conclusions, and therefore it becomes important to. 
direct the attention of readers of Nature to the fact 
that the example taken is an extremely bad one. ~ 
Prof. Bergson states that the eye of Pecten agrees in 
the most minute details with the vertebrate eye. Now 
there is no resemblance whatever either in structure 
or development between the two. The only feature 
possessed in common by both eyes is an inverted — 
retina, and this is by no means unique in the animal 
kingdom. W. J. Dakin. 
University of Liverpool, March 19. 
Mersenne’s Numbers. 
Ar various times Nature has inserted notices of 
the successive discoveries in relation to Mersenne’s 
Numbers. In the issue of August 12, 1909, Colonel 
Cunningham’s discovery that 228479 was a factor of 
2P—r1 when p=71 was announced: the other factor 
Was 10334355036337793, but whether this was a prime 
or not was left undetermined. The same result was 
discovered last January by Mr. Ramesam, of Myla- 
pore, Madras, and he subsequently resolved the 
larger factor into the product of 48544121 and 
212885833. I think these results may be of interest 
to some of your readers. 3 
W. W. Rouse Bai. 
Trinity College, Cambridge, March 23. 
The Electrolytic Transportation of the Active Deposit 
of Actinium through Pure Water. 
In the course of some detailed investigations on the 
conditions of the electrolysis of some radio-active pro- 
ducts, I have encountered in the case of actinium the 
following phenomenon. The products of the active 
deposit of actinium, though apparently not soluble in 
water under ordinary conditions, under the action of 
electric force could be driven from the anode in the 
state of ions into the water, and eventually trans- 
ported to the kathode. The experiments were as 
follows. 
The active deposit of actinium was collected on the 
surface of a platinum plate exposed during some 
hours as a negative electrode in the emanation of 
actinium. Immediately after the removal of the 
plate from the emanation, its activity was measured 
by means of an electrometer, and the beginning of 
the curve of its decay was determined. The plate 
was then immersed in pure, several times distilled 
water, and formed the anode during the electrolysis 
of the water. The kathode was also a platinum plate. 
The activity of the anode was again measured after 
the electrolysis. It could be seen that the plate was 
in certain conditions deprived by the electrolysis of a 
great part of its activity, especially in the case when 
a very great electromotive force (220 or 440 volts) was 
applied. If the current passed through the water 
during a longer time (2 or 3 min.), and the distance 
between the electrodes was not too great (1 or 2 cm.), 
a great part and often the total activity lost on the 
anode could be detected on the kathode. The activity 
of the kathode proceeded not only from actinium C 
and probably actinium D, but also the product 
