636 
NATURE 
[AuGusT 22, 1912 
whole of the North Atlantic between ca. 25> and 
ca. 45° N.L. Of these the specimens from west 
of ca. 20° W. were the smallest in size, namely, 
34-6 cm. 
To make quite certain of the forms we were 
dealing with, it has been necessary to examine 
thousands of eels, not only from the continents, 
but also from all the Atlantic islands where the 
eel occurs (Iceland, Faeroes, Madeira, Canaries, 
Azores, Bermudas, and the West Indies). The 
result is also shown on Fig. 2. There are only 
two species of eel in the North Atlantic region, 
an é€astern (A. vulgaris), which has its western 
limit at the Azores, and a western (A. rostrata). 
A further result has been that the stocks are prac- 
tically unmixed, each being restricted to its own 
region. On counting the vertebrae (myomeres) in 
our larve from the Atlantic, we were now able to 
prove that only the larvee taken west of the Ber- 
mudas belonged to A. rostrata, whilst larve of 
A. vulgaris were found in large quantities as far 
Q 
west as 53° W.L.—though, as mentioned, the | 
Pere] gh, 
western limit of the adult is at the Azores, ca. 
30° W. The larvee may even occur further west. 
The question is, now, whether we can prove that 
the smaller larve (34-6 cm.) from the central part 
of the Atlantic are the product of the main stock 
of 4. vulgaris, which lives on the European con- 
tinent. It might be thought, for example, that 
the larvae found near the Azores come from the 
stock living on those islands; but, fortunately, we 
have now obtained from the Gulf Stream south of 
Newfoundiand, 53° W., such a large number of 
half-grown larve that the quantity alone seems to 
exclude the possibility that they can spring from 
the inconsiderable stocks on the Azores or other 
Atlantic islands. The distance from Europe of the 
place in the Gulf Stream where they were found, | 
is ca. 2000 miles, but there can be no doubt that | 
they traverse this distance with the currents, for 
we have found the intermediate stages on the way, 
and another species, Synaphobranchus pinnatus, 
whose full-grown larve are found in quantities 
west of Europe in company with those of the eel, 
has the same‘distribution. 
We see from the Chart and Table how the larve 
of A. vulgaris are distributed in a very charac- 
teristic manner according to age or size, over the 
whole of an enormous area, by comparison with 
which the distances in the Mediterranean seem 
small. We have not yet attained to the full solu- 
tion of the exceedingly difficult eel problem, but the | 
steady progress of the last twenty vears is full | 
of promise for the future. We cannot say exactly 
where the eel spawns, though the Sargasso Sea 
is perhaps a principal spawning region, but con- 
tinued collections and investigation of the currents 
will assuredly lead to the discovery of the eggs 
DD~ 
and earliest larve, perhaps not in deep water, as | 
Grassi imagined, but nearer to the surface. There 
is even perhaps reason to believe that the eel 
spawns in the intermediate layers and not on the 
bottom. Altogether, the whole story of the eel 
and its spawning has come to read almost like a 
romance, wherein reality has far exceeded the 
dreams of phantasy. Jous. ScHMIptT. 
NO. 2234, vor. 89] 
THE FIFTH INTERNATIONAL CONGRESS 
OF MATHEMATICIANS. 
“THE International Congress of Mathematicians, 
which meets in Cambridge on August 22, is 
the fifth of a series inaugurated at Zurich in 1897 
and continued in Paris, 1900, Heidelberg, 1904, 
and Rome, 1908. The inviting body is the Cam- 
bridge Philosophical Society, and the project of 
receiving the fifth Congress at Cambridge has 
been well supported, not only by Cambridge men, 
resident and non-resident, but also by others, in 
Oxford and in the country generally, who are 
interested in the progress of mathematics. 
The congress is organised in four sections, 
devoted respectively to analysis, geometry, 
applied mathematics, and philosophical, historical, 
and didactical questions. The Section of Applied 
Mathematics is divided into two departments, one 
dealing with mathematical physics and astronomy, 
and the other with economics and statistics. Each 
section appoints its own chairman from day to day, 
the chairman for the first day being chosen by an 
international committee from among those persons 
who, in the preparation for the congress, have 
been charged with the duty of collecting papers for 
the sections. The sections also appoint their own 
secretaries. The work of preparation has been in 
the hands of an organising committee, presided 
over by Sir George Darwin, and having as 
treasurer Sir Joseph Larmor, and as secretaries 
Prof. E. W. Hobson, of Cambridge, and Prof. 
A. E. H. Love, of Oxford: 
Owing to the great interest which is now taken 
in the study of improved methods of teaching, the 
department dealing with didactical questions has 
attracted to the congress many adherents interested 
in questions concerning the teaching of mathe- 
matics. Associated with this department is an 
international commission appointed at Rome four 
years ago to collect information in regard to the 
methods pursued in various countries, and to study 
the directions and effects of recent changes. In 
Great Britain the work of collecting this informa- 
tion has been done by an advisory committee of 
the Board of Education, and the information has 
been incorporated in a series of reports issued by 
the Board and now collected in two large volumes. 
These are intended for presentation to the con- 
gress, and similar reports have been compiled with 
the same view in Germany and the other coun- 
tries. 
In addition to the sectional meetings of the 
congress, there will be plenary sessions, at which 
lectures will be delivered, as follows :—‘‘ Boundary 
problems in one dimension,” by Prof. M. Bécher, 
of Harvard; “Définition et domaine d’existence 
des fonctions monogénes uniformes,”’ by Prof. E. 
Borel, of Paris; “ Periodicity in the solar system,” 
by Prof. E. W. Brown, of Yale; “Il significato 
della critica dei principii nello sviluppo delle 
matematiche,” by Prof. F. Enriques, of Bologna; 
“The principles of instrumental seismology,” by 
Prince B. Galitzin, of St. Petersburg; ‘‘ Geléste 
und ungeléste Probleme aus der Theorie der 
Primzahlverteilung und der Riemannschen Zeta- 
