May 13, 1915 | 
NATURE 
299 

faced horses; the other by the pony-like, broad-faced 
horses, especially the Celtic pony and the fjord horses 
of Norway. 
AN interesting summary of the ‘‘ Natural History of 
the Whale-sharlk"’ (Rhineodon typica), by Prof. E. W. 
Gudger, is given in the March number of Zoologica, 
the organ of the New York Zoological Society. Little 
is known of this fish, the largest of the sharks, and 
estimates of its length vary immensely, but it would 
seem that its maximum length is about 45 ft. Prof. 
Gudger’s summary is based upon a specimen captured 
at Miami, Florida, during June, 1912. Unfortunately, 
howeyer, he is able to write at first hand only of the 
stuffed skin of this fish, for the rest he has had to 
rely on photographs, and the account of Capt. Thomp- 
son, who harpooned it. He nevertheless brings to- 
gether some valuable notes on its coloration, habits, 
and food, compiled from various sources. 
In ‘‘Notes on the Evidences of Age Afforded by 
the Growth Rings of Oyster Shells’? (Fisheries, Ire- 
land, Scientific Investigations, 1913, ii. [1914]), Miss 
A. L. Massy gives particulars of measurements and 
of the number of surface lamella of the shells of 
more than 600 oysters of known age and of various 
ages from eighteen months to six years. Summing 
up her observations as to the relation between age 
and the number of surface lamella, or growth rings, 
Miss Massy states that an oyster of eighteen months 
or two summers appears to possess at least two rings, 
but may have as many as five; one of three summers 
has at least two rings, but may have six. A four- 
year-old oyster may have only three rings, or may 
possess seven or eight. It would have added greatly 
to the interest of the paper if these surface rings 
had been compared with the number of rings shown 
in sections of the shell. 
PUBLICATION DE CirconstTance, No. 60, of the Inter- 
national Council for the Study of the Sea is entitled 
‘A Contribution to the Biology of the Mackerel: In- 
vestigations in Swedish Waters,’ by David Nilsson. 
The subjects dealt with are the relation of length 
to weight in the mackerel, age and growth, food, 
parasites, sex and maturity, eggs and larve, and 
variation. The material examined, which was col- 
lected off the west coast of Sweden, was unfortunately 
not very large; indeed, scarcely sufficient to justify 
many of the conclusions which the author attempts 
to draw from it. On the question of age and growth 
both the scales and the otoliths have been examined, In 
the mackerel, however, the appearances seen on both 
of these are very difficult of interpretation, and the 
figures given in the paper, which are reproductions 
(perhaps not very good ones) of photographs, are 
not very convincing. The author considers that 
mackerel of 120 to 210 mm. long in August, Sep- 
tember, and October are derived from eggs spawned in 
the same year, although he shows that spawning in 
Swedish waters takes place principally in July. Much 
further research on a far more extensive scale is 
required before our knowledge of the life-history of 
the mackerel can be regarded as adequate and trust- 
worthy. 
NO, 2376, VOL. 95| 
In his report on the survey operations for the year 
1913-14 (New Zealand Department of Lands and 
Survey) Mr. E. H. Wilmot, who has recently taken up 
the duties of Surveyor-General, sets forth the worl: 
of the year and shows the steady progress which has 
been made. Work on the second-order triangulation 
seems to have been mainly preparatory for future 
field work, and to include the computation of observa- 
tions previously made. The magnetographs at the 
observatory were kept continuously in operation, and 
the discussion of the field observations of the magnetic 
survey is well advanced. The observatory also co- 
operated with the staff of Captain Scott’s Antarctic 
Expedition in pendulum observations, determination 
of times, transmission of time signals, etc., rendering 
thereby much valuable assistance to the expedition. 
An appendix treats briefly of the measurement of the 
Kaingaroa base, about 11-5 miles in length, for the 
second-order triangulation. The probable error of the 
measurements is small, but a complete discussion of 
the base and its relation to others in the network 
cannot yet be given. 
THE two sections of Science Abstracts issued April 
26 do not show any marked decrease in the number 
of scientific papers with which the publication has to 
deal in the interval between two issues. The Physics 
Section extends to forty-eight and the Engineering 
Section to forty pages. We notice in the former 
abstracts from the autumn and winter numbers of 
the Annalen der Physik, but there is nothing in the 
Engineering Section to correspond. 
THE Scientific American for April 17 describes the 
American form of the metal-spraying “pistol”? in- 
vented by a Swiss engineer, Mr. Schoop. A thin 
metal wire is fed at a suitable speed through the tube 
of a Bunsen burner into the flame, in which it is 
melted. At this point it is subjected to a rapid blast 
of air which blows it out of the mouth of the Bunsen 
in a stream of extremely fine particles. The apparatus 
is held in the hand very much like a pistol, and the 
jet may be directed on to any object which it is 
desired to cover with a thin film of the projected 
metal. The spray does not appear to damage the. 
object on which it is deposited, and brass has been 
deposited on silk without its texture being injured. 
“Tue ‘Appeal to Non-Producing Mathematicians,’” 
recently published by Mr. Paaswell in the Bulletin 
of the American Mathematical Society, and noted im 

NaTuRE, January 14, 1915 (vol. xciv., p. 541), 
has received a reply from Prof. C. N. Haskins- 
in the April number of the Bulletin (vol. xxi., 
No. 7, p. 343). It will be remembered that 
Mr. Paaswell directed attention to. certain out- 
standing mathematical problems of engineering, 
and comment was made in these columns on _his- 
omission of reference to aeroplane investigations. It 
would seem, from Prof. Haskins’s comments, that 
engineers do not find it possible to add to their quali- 
fications the training necessary to cope with such 
problems, and he suggests the desirability of mathe- 
maticians adding the necessary engineering to their 
| mathematics. Unfortunately, however, when mathe~ 
