DECEMBER 24, 1903] 
NATURE 173 
siderable service. Practically all one can say to a 
traveller is that he should collect full information about 
everything, and books of this kind are valuable in 
suggesting topics for inquiry. 
Catalogue of the Lepidoptera Phalaenae in the British 
Museum. Vol. iv. Catalogue of the Noctuidz in 
the Collection of the British Museum. By Sir 
George F. Hampson, Bart. Pp. xx+689, plates 
lv.-Ixxvii., and 125 woodcuts. (London: Printed 
by Order of the Trustees.) Price 15s.; plates 16s. 
THE previous volumes of this important work appeared 
in 1898, 1900, and r1gor respectively, and we have now 
to record the publication of vol. iv., which includes the 
Agrotine, the first of the fifteen subfamilies into which 
the great family of Noctuide is divided; 1139 
Agrotinz are described in the present volume, out of 
the 10,000 to 12,000 known species of Noctuide. 
As the Agrotinz are well represented in Europe and 
North America, this volume will perhaps appeal to a 
larger number of lepidopterists than its predecessors, 
which treated of more showy, but principally tropical, 
moths. For the plates of Agrotina  trichromatic 
photography has been employed, as more suitable to 
represent the generally dull colours of the Noctuide 
than chromolithography, which is considered better 
adapted to bright coloured moths, such as Arctiade. 
Most of the leading lepidopterists of Europe and 
America have helped to make Sir George Hampson’s 
work more complete by the contribution of specimens, 
or coloured photographs of unique types, and the loan 
of co-types. 
Descriptions of the known larve of Agrotinze are 
added from various authentic sources, those of North 
American species being mostly contributed by Dr. 
Harrison G. Dyar. 
The general arrangement of the book is in all re- 
spects similar to that of previous volumes, and the 
execution of the plates is excellent, though one or two 
figures may perhaps be somewhat undercoloured—not 
a very serious point, however. 
There are small matters on which we think inform- 
ation, when attainable, might have been added, such 
as the elevations between which mountain species 
occur (which is only rarely mentioned) and the lati- 
tudes at which Arctic species have been found. 
As we may reasonably assume that the increase of 
our knowledge of moths will be still more rapid in the 
future than it has been in the past, we can hardly 
expect Sir George Hampson to complete the Noctuidze 
in less than ten or twelve volumes. At a rough esti- 
mate it is probable that out of the 1139 species described 
in vol. iv. less than 300 may have been included in 
Walker’s catalogue of 1856-1866. Rather more than 
100 species of Agrotinz have been described by Sir 
George himself, either for the first time in the present 
volume, or in previous publications. 
Proceedings of the London Mathematical Society. 
Vol. — Pp. 476. (London: Francis Hodgson, 
1903. 
A SPECIAL interest attaches to the present volume from 
the fact that it marks the retirement from the 
secretaryship of Mr. R. Tucker after thirty-five years 
of office. Mr. Tucker was elected a member of the 
Society on October 16, 1865, and two years later he 
succeeded G. C. de Morgan as secretary. Mr. Tucker 
has been responsible for the greater part of the editorial 
duties connected with the issue of the Proceedings 
from part xii. onwards, and he has succeeded in pro- 
ducing a series of English mathematical transactions 
of which he may well feel proud. 
Among the subjects treated in this volume we note 
Dr. Hobson’s presidential address on the infinite and 
NO. 1782, VOL. 69] 
the infinitesimal in mathematical analysis, and papers 
by Mr. Conway on light propagation in a uniaxial 
crystal, by Prof. A. C. Dixon on summation of series 
and expansion of functions, by Prof. Hill on power 
series, by Prof. Lamb on wave motions, by M. Picard 
on existence theorems for differential equations (in 
French), by Mr, Whittaker on harmonic analyses, by 
Mr. W. H. Young on sets of points and intervals, and 
many other papers of equal interest. 
Insist on Yourself. The only Law of Success. Pp 
45. (London: Gay and Bird, n.d.) Price rs. net. 
Tuis little book is intended to set forth concisely many 
of Emerson’s utterances on the importance and power 
of individuality. The ‘‘thoughts’’ selected are 
attractively arranged and nicely printed. 
LEAVE Sil On ne ws DOR. 
{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 “atcrr. 
No nctice is taken of anonymous communications. | 
The Unusual Sky Colours and the Atmospheric 
Circulation, 
Pror. F. A. Foret writes me concerning my letter in 
vol. Ixviii. p. 623, that although he did not himself observe 
the coloured ring around the sun prior to the first of last 
August, yet he has been informed that it was seen in 
Europe much earlier. The observers and dates quoted by 
M. Forel, arranged by localities from north to south, are 
as follows :—Director Rykatcheff, of the Central Physical 
Observatory at St. Petersburg, noted an opalescent veil 
surrounding the sun on October 5 and November 9, 1902, 
January 21, February 10, 18 and 23, March 17, April 5, 
May 29, and July 26, 1903. Dr. Busch, at Arnsberg, West- 
phalia, saw the same thing on November 19, 1902, March 
21 and 22, 1903, and Prof. Wolf, at Heidelberg, during 
January, 1903. Dr. Maurer, at Zurich, observed the ring 
also in January, on March 27 and 28, June 7, 8, 9, and at 
the end of July, 1903. Therefore, M. Forel says, very 
properly, that since the phenomenon was_ observed 
practically simultaneously in Europe and America, no 
hypothesis as to why it appeared first in the last named 
country is needed. While admitting the truth of the state- 
ment, I would remark that a faint whitish ring around the 
sun was recorded by me here as early as June 26, 1902, 
although it was not noticed again until the close of the year. 
The equally early appearance over southern England of a 
large brownish corona, which became smaller but more 
conspicuous during the summer and autumn of 1902, is de- 
scribed by Mr. T. W. Backhouse in Nature (vol. Ixvii. p. 
174). 
M. Forel pointed out in the Comptes rendus of the French 
Academy of Sciences for August 10 that in view of the 
intermittent character of the brilliant colours of the western 
sky after sunset during the preceding year, produced, he 
assumed, by the breaking up of the continuous ring of 
volcanic dust into separate cloud masses which passed 
successively over Europe, it became of interest to ascertain 
whether the present Bishop’s ring, unlike its predecessor, 
was always visible in favourable circumstances. The 
data mentioned, as subsequently sent M. Forel, proved that 
the new Bishop’s ring was visible only at irregular in- 
tervals, as he had surmised. Now, if this phenomenon, as 
well as the discontinuous sunset glows, were caused by the 
passage of isolated masses of volcanic dust, it seems 
possible, by comparisons with observations at distant 
stations, not only to trace the direction of their drift, but 
also to determine their approximate velocity. Accordingly, 
the records at Blue Hill of the occurrence of Bishop’s ring 
and of abnormal glows after sunset during the past year 
were examined, and the tendency of both phenomena to 
occur intermittently, but not necessarily simultaneously, was 
established, even though the transparency of air remained 
nearly constant. 
