JANUARY 10, 1907] 
NATURE 2 
power of the Cairo gas is determined, and where 
paint, oils, cement, asphalt, &c., are tested for com- 
mercial purposes. Further, the purity of the water 
supply of Cairo demands constant attention, while the 
river water and the silt which the Nile carries in 
suspension during a large portion of the year have 
to be repeatedly examined. These are matters which 
must be passed over with a bare mention, though 
doubtless the management finds the addition of such 
investigations sufficiently exacting. 
More immediately connected with the work of the 
department appear to be the hydrographic survey of 
the Nile and river gauging. For the efficient examin- 
ation of questions connected with this subject a per- 
manent gauging station has been erected at Sarras, 
thirty-three miles below Wady Halfa, and here are 
measured in various ways some of the factors that 
determine the quantity of water in the river. The 
work is hardly out of the experimental stage at pre- 
sent. A main object is to determine the most appro- 
priate kind of apparatus that will give accurate 
results with the least expenditure of labour. This 
section is very interesting, and tables are added 
showing the volume of water discharged in cubic 
metres per second, and the mean velocity per second, 
with other details. The velocity and volume both 
increase up to the end of August, when, unfortu- 
nately, observations were discontinued, though the 
time of maximum was not reached. A preliminary 
discussion of the results has shown that the volume 
of the discharge at Khartoum, when the Atbara was 
not contributing, was greater than that at Aswan by 
amounts which could not be explained by loss from 
evaporation or from use in irrigation. The cause of 
the loss is not yet decisively explained, though Captain 
Lyons makes a plausible suggestion. 
Another feature of the report is the description of 
the Helwan Observatory, which seems to be very 
fairly equipped with magnetic, meteorological, and 
seismological instruments. Of the astronomical por- 
tion, we learn that the 30-inch reflector presented to 
the Egyptian Government by Mr. R. H. Reynolds, of 
Birmingham, is in course of erection, and that all the 
heavy castings are in position. Some of the 
mechanism has been returned to England for alter- 
ation, and the completion of the erection awaits the 
return of these essential fittings. 
Of the geodetic work properly so-called, details are 
given of the second order triangulation with all neces- 
sary fulness. The standard of accuracy attained is 
not quite that of the highest order, but sufficient for 
the object for which the measurement was under- 
taken, namely, the control of the map sheets used in 
the revenue survey of the country. It is now possible 
to base a map of Egypt on a connected triangulation 
from Damietta to Wady Halfa, an extent of nine 
degrees. Of even greater importance, however, is the 
triangulation, which it is to be hoped will be ulti- 
mately carried out, whereby Egypt will contribute to 
the measurement of the arc of meridian, which in 
its entirety will extend from the Cape of Good Hope 
to the North Cape, along the thirtieth parallel of east 
longitude. For several years Sir David Gill has been 
engaged in carrying this chain of triangulation north- 
ward, and the prospect of completing a measured 
arc of some 100° of latitude cannot but be of pro- 
found interest to the astronomer, the geologist, and 
the physicist. Captain Lyons, however, is fully aware 
that the value of such a work consists very greatly 
in the maintenance of the same standard of accuracy 
throughout. The most difficult problem of geodesy, 
he tells us, is to pass from a particular platinum and 
iridium bar, on which the length of the metre is de- 
fined, to the length of a base line over a more or 
NO, 1941, VOL. 75] 
less rough land surface with as great an accuracy as 
possible. Viewed in this light, the most interesting 
portion of the report consists in the description of the 
method of the comparison of the bars and Jaederin 
wires used in Egypt. The accuracy seems quite 
satisfactory. We EP. 
INTERNATIONAL FISHERY 
INVESTIGATIONS. 
HE results of the first two or three years of 
active investigation in connection with the 
general scheme of fishery research, which is being 
carried out in the seas around north Europe under 
the auspices of the International Council for the 
Exploration of the Sea, are now being rapidly pub- 
lished in a series of reports issued in part by the 
Bureau of the International Council and in part by 
the authorities of the different countries participating 
in the international scheme. As the outcome of the 
work is being thus gradually brought to light, the 
comprehensive character of the programme becomes 
increasingly obvious. The remarkable _ scientific 
interest of the results ‘obtained from what is prob- 
ably the greatest and most serious attempt yet made 
to carry out a scientific investigation by means of 
international cooperation is placed beyond dispute, 
nor can it be doubted that the eventual practical 
benefit of these researches will be of even more 
importance and of much direct value to the fishing 
industry. 
The first report under review contains detailed 
accounts of some of the work carried out in 1902 
and 1903, whilst in the Marine Biological Journal 
Mr. James Johnstone, of the Liverpool University 
Fisheries Laboratory, gives a useful résumé of the 
results published up to the summer of 1906. The 
remaining reports deal for the most part with more 
recent publications. 
As must be by this time well known, three main 
lines of research are being developed in the inter- 
national scheme, the hydrographical, the biological, 
and the statistical The hydrographical investiga- 
tions record and endeavour to explain the constantly 
changing physical conditions under which fishes pass 
their lives; the biological investigations aim at a 
complete account of the life-history of the more 
important food-fishes, as well as a detailed knowledge 
of the various smaller marine creatures which serve 
as the food of fishes; the statistical investigations deal 
primarily with the variations in the actual quantities 
of fish removed from the different fishing-grounds and 
brought to market, and at the same time yield con- 
siderable material which is capable of supplementing 
and amplifying the knowledge of the history of the 
fishes obtained from the biological observations. 
Although the three branches of the investigation are 
for practical reasons carried out more or less in- 
dependently, the ultimate success of the work depends 
upon the judicious combination of the knowledge 
gained from each, and its application to particular 
problems of the fishing industry. 
A striking example of the success of such a combin- 
1 Reports of the British Delegates attending the Meetings of the Inter- 
national Council for the Exploration of the Sea in 1903, 1904 and 1905, and 
Reports and Correspondence relating Thereto. “Vol. ii., General Report of 
the International Council for 1902-1904 [Cd. 3033]. A Reprint of Conseil 
permanent international! pour |’Exploration de la Mer. Rapports et Procés- 
Verbaux, vol. iii. (London: Printed for H.M. Stationery Office.) 
Conseil permanent international pour !’Exploration de ]a Mer. Rapports 
et Procés-Verbavx, vols. v. and vi.; Bulletin trimestriel des Résultats 
acquis pendant les Croisiéres périodiaues et dans les Périodes intermédiaires, 
Année 1905-1006, No. 3, Janvier-Mars, 1906; Bulletin statistique des 
Péches maritimes des Pays du Nord de l'Europe, vol. i.. pour les Années 
1903 et 1904. 
Journal of the Marine Biological Association of the United Kingdom, 
vol. vii., No. 5. 
