Marcu 25, 1915] 
NATURE 93 
do 

The author’s experience and ingenuity in 
applying X-ray methods to localise the position of 
foreign bodies are so well known that when he 
comes forward with improved methods of electric 
probing, which have the distinguishing merit of 
the utmost simplicity, we may be sure they will 
find immediate and extensive application. 

GEODETIC SCIENCE. 
IN? 3 of the new series of professional papers 
of the Ordnance Survey contains some ex- 
cellent notes on the geodesy of the British Isles, 
by Colonel Close, R.E., which bring the position 
of geodetic achievement fairly up to date, and 
incidentally add some historical indications of the 
processes by means of which our position in the 
world of geodetic science has been secured. Their 
usefulness has been increased by the addition of 
a very ample bibliography of the science, and by 
simple diagrams illustrating certain special 
features affecting geodetic levelling, including the 
principal triangulation of Great Britain, the geo- 
graphical position of the West European meri- 
dional arc, and of the European longitudinal arc. 
In the section of the pamphlet dealing with stan- 
dard measurement it is interesting to observe that 
the national standard yard, which was legalised in 
1855, consists of a marked length on a bronze bar 
bearing a definite relationship to the “‘inter- 
national” metre (also a measured length on a bar), 
which was originally intended to represent one 
ten-millionth of the length of the earth’s meridional 
quadrant. 
Colonel Close’s sketch of the various operations 
undertaken to determine the figure of the earth, 
dating from Airy’s investigations of 1830 to 
Helmert’s determination of 1906, proves incident- 
ally the extraordinary value of the early investi- 
gations undertaken with inferior instruments. 
On Airy’s figure the whole of the mapping of the 
United Kingdom still depends, nor have the 
results deduced from the reduction of the prin- 
cipal triangulation affected the map values. In the 
length of 700 miles from Shanklin to the extreme 
north of the Shetlands Airy’s figure gives about 
four seconds in latitude too much, if we accept 
Helmert’s figure as the criterion. This does not 
affect the linear accuracy of the map. Three 
figures were computed by Colonel Clarke (in 1858, 
1866, and 1880 respectively) from the data fur- 
nished by the reduction of the principal triangula- 
tion. They are all in use, either in Africa or 
America. The mean value in length determined 
by Clarke of the semi-axis major of the ellipse, 
the revolution of which about its minor axis pro- 
duces the spheroid of the earth’s surface, is less 
than that of Airy and only slightly greater than 
that of Helmert. Colonel Close records his 
opinion that the probable value is somewhat 
greater than Clarke’s mean. 
Many people must have noticed the apparently 
haphazard way of recording “bench” marks by the 
Ordnance Survey to indicate altitudes determined 
by levelling. They are to be found on most un- 
NO. 2369, VOL. 95] 


substantial walls, on milestones, and even on gate- 
posts, and they must, many of them, inevitably 
be unstable. In the section of the pamphlet 
dealing with levelling, Colonel Close indicates the 
method by which, in future, such marks will be 
rendered permanent. Concrete blocks will be sunk 
on to hard rock foundations at intervals of about 
twenty-five miles all over the country; a bolt of 
bronze, with a knob of flint being embedded in 
the concrete. This section is also of interest 
as a record of the difficulties experienced in 
dealing with the adopted datum of mean 
sea-level. Indian survey investigations have 
contributed largely to the solution of this 
troublesome problem. It is in India, too, under 
Colonel Sir S. Burrard, that the most com- 
prehensive investigations have been made in the 
matter of the deflection of the level, and the 
apparent eccentricities of the force of gravity, in- 
cluding the difficult problems which beset the 
speculative subject of isostasy ; but Colonel Close’s 
references to early English methods of determining 
the value of deflection due to local topography 
are extremely interesting as a record of the first 
steps taken in the evolution of this special branch 
of geodetic science. These plain and intelligible 
notes on a highly complicated subject, being en- 
tirely free from any affectation of technical special- 
ism, should attract a much wider range of scientific 
interest than is indicated by the title of Ordnance 
Survey Professional Papers. T. H. Hovpicn. 

SCIENTIFIC FACTORS OF INDUSTRIAL 
SUCCESS. 
(pete Institute of Industry and Commerce (now 
the Institute of Industry and Science), so the 
introductory leaflet states, is a counterpart of a 
German organisation known as the Hansa Bund. 
How the Hansa Bund arose or by whom and 
when it originated we have no knowledge. It is 
a confederation of important German firms for 
promoting, encouraging, and facilitating German 
home and foreign trade. It is proposed by similar 
means, but on somewhat “superior lines,” to do 
the same for British industry, and the directors 
invite those interested in the development of our 
industries by the aid of science to enrol them- 
selves as members. A portion of the revenue of 
each year is to be devoted to scientific research 
under the supervision of our most eminent men 
of science. Accompanying this leaflet are a 
number of brochures touching on the causes and 
effects of German commercial success and on the 
remedies for British commercial decline. 
If “in the multitude of counsellors there is 
safety,” in the diversity of their opinions there 
may also arise confusion. Sir W. Ramsay con- 
ceives that the main purpose of the Institute is 
to combat German industrial methods, which are 
said to be organised on a policy of dishonesty 
and trickery. This is to be undertaken by the 
State by adopting something of their methods, or 
by endeavouring to thwart them. Mr. S. Roy 
Illingworth, in his pamphet on “The Organisation 
