
AvuGusT 5, 1915] 

here so well developed. The provision of a small- 
scale coloured map of the ‘solid’? geology marks an 
important advance on the earlier edition. Plate ii., 
which should face p. 16, is absent from the copy we 
have examined. 
Tue report of the Fernley Observatory at Southport 
for the year 1914, prepared by Mr. Joseph Baxendell, 
meteorologist to the Southport .Corporation, gives re- 
sults of considerable interest. The observations have 
been systematically continued for the last forty-three 
years, and the values give a good average for inter- 
comparison. A table is given showing the diurnal 
variation of the winds from different directions for the 
whole year, based on the observations of fifteen years 
to 1913, and a diagram shows the summer wind-direc- 
tion frequencies for the same period. The great pre- 
valence in summer of sea winds, from west and north- 
west, is well indicated, and there is a much greater 
prevalence of these winds in the day than in the night 
Detailed tables of the several meteorological elements 
are given for 1914. The warmest month was August, 
with a mean temperature of 60:6°, which, however, is 
only o-7° warmer than July, while the coldest month 
is January, with the mean temperature 39:9°. The 
temperature during the year ranged from 80° to 22°. 
The rainfall for the year was 32-02 in., and the 
wettest months were July and December, the per- 
centage of the average being respectively 159 and 165. 
The brightest month was June, with 234 hours’ sun- 
shine, whilst April and August were very nearly as 
bright. 
VOL, Xxxv., part i., 1913, of the Annals of the 
Royal Central Office of Meteorology and Geodynamics 
of Rome contains a long memoir by Prof. Palazzo 
describing magnetic observations which he took during 
June, July, and August of 1913 in the Italian colony of 
Eritrea bordering on the .Red Sea. The principal 
instruments employed were a magnetometer and dip 
circle by Dover. Observations were taken at sixteen 
stations situated between 14° 47! N. and 15° 47’ N. 
One of the stations was on an island in the Red Sea, 
the others on the mainland, mostly at considerable 
heights, in one case 2410 metres above sea-level. The 
results are summarised on p. 75. A chart at the end 
shows the stations, and includes isogonals for 1° 30! 
to 1° 50’ W., isoclinals from 11° o! to 13° o! N., and 
lines of equal horizontal intensity. The isoclinals are 
nearly parallels of latitude. On p. 89 there is a record 
of results by other observers in Eritrea. At Massaua 
(Massowah), on the Red Sea, there were in all results 
from eight observers, including Prof. Palazzo, the 
earliest going back to 1839. Conclusions are drawn 
from these as to the secular change. A summary of 
the results also appears in a short paper by Prof. 
Palazzo in the Rendiconti Accademia dei Lincei, 
January, 1915. 
Tue July number of the Journal of the Réntgen 
Society contains the paper which Mr. F. Harrison 
Glew read before the Society in April, describing a 
new mechanical effect of the a rays from radio-active 
bodies. Mr, Glew finds that if a very thin strip of 
mica has one side exposed to a rays for a week or 
two the strip is bent, the side exposed to the rays 
NO. 2388, VOL. 95] 
NATURE 

627 

becoming convex and displaying iridescent colours. 
In one experiment a strip 2 mm. by 11 mm. and 
oor mm. thick was exposed for a month to the a rays 
coming from a mica-covered capsule containing two 
milligrams of mesothorium. The strip was supported 
at one end so as to be 3 mm. above the cover of the 
capsule. It was found to have acquired a curvature equal 
to that of a circle of radius 48 mm. and required a weight 
of 460 milligrams applied to its middle point to straighten 
it. When reading his paper Mr. Glew suggested that 
the a particles arrested by the mica existed as occluded 
helium in the strip, an opinion which has since been 
verified by Mr. J. H. Gardiner, who on heating a 
strip in vacuo obtained the helium spectrum. 
Tue U.S. Department of Commerce has published 
a second edition of Circular No. 20 of the Bureau of 
Standards. The circular presents briefly, in its first 
section, the principles underlying the construction and 
operation of commercial electrical measuring instru- 
ments. This is followed by a particularly useful 
section on the performance of such instruments; the 
subjects discussed include accuracy, sensitivity, relia- 
bility, the effects of temperature change, temperature- 
coefficients, the effects of stray magnetic and electro- 
static fields, the effects of imperfect elasticity of springs 
and of friction, and the construction of scales. The 
information on the temperature-coefficients of volt- 
meters and ammeters is very useful, and methods are 
suggested for compensating for ordinary temperature 
changes. The last section contains valuable hints on 
the testing of instruments; it discusses in detail the 
application of the potentiometer to the measurement 
of voltage and current. Owing to its smaller tem- 
perature-coefficient, the Weston portable cell of the 
unsaturated type is recommended as being preferable 
to the Weston normal cell, in which saturated solution 
is used. The circular may be obtained from the Super- 
intendent of Documents, Government Printing , Office, 
Washington, D.C. 
Tue valuable reports and other publications issued 
by the British Fire Prevention Committee have fre- 
quently been referred to in these columns. The war 
emergency work accomplished by the committee 
during the past twelve months has been of a very 
extensive character, and is a remarkable example of 
what can be done entirely gratuitously by voluntary 
workers. The following are special features of the 
work dealt with by the committee during the first year 
of the war :—Fire Survey Force: At the outbrealx of 
war, the committee formed a special Fire Survey 
Force of roo surveyors to undertake at short notice 
any fire surveys required by the Government in an 
honorary capacity. Above goo establishments taken 
over for war emergency work all over the country 
were surveyed by this force, with a total of more than 
40,000 beds. Latterly re-surveys are made in cases of 
special fire risk. Fire Warnings: The warning ser- 
vice embraced the preparation and free issue of a 
large number of public “fire warnings ”’ in connection 
with the war emergency, disseminated by the com- 
mittee in the form of posters, circular letters, or as 
notices reproduced by the Press, etc. The total issue 
of posters and like publications exceeds 200,000. Fire 
