698 
the mortar is not only dependent upon efficient burn- 
ing, but also on skilful slaking and proper mixing. 
The deterioration in the quality of quick- and slaked- 
lime with keeping also receives attention. 
AnoTHER of Prof. H. B. Baker’s interesting studies 
of the properties of purified substances is described in 
a recent issue of the Chemical Society’s Journal, 
vol. ciii., p. 2060, in a paper published jointly with 
Mr. L. H. Parker. Two years ago, at a meeting of 
the Faraday Society, an experiment was shown in 
which water prepared under special conditions acted 
much more slowly than ordinary distilled water on 
sodium amalgam. It was remarkable that this differ- 
ence persisted even after a considerable amount of 
caustic soda had been formed; it was therefore not 
due to the non-conducting properties of the special 
water, and has now been traced to the ‘catalytic 
action”’ of traces of hydrogen peroxide. These are 
present in ordinary samples of water, and in water 
prepared from pure hydrogen and oxygen in presence 
of palladium, but are destroyed by distilling from 
metallic vessels and superheating the steam. One 
sample of water prepared in this way in a platinum 
apparatus had no perceptible action on sodium amal- 
gam in three hours, and liberated only o-1 c.c. in four 
hours, 0-4 c.c. in five hours, and 0-6 c.c. in six hours. 
On the other hand, the addition of one part of 
hydrogen peroxide to 100,000 parts of another sample 
of water increased the amount of hydrogen liberated 
from o to 3:8 c.c. in one hour, and 4-1 to 32-4 c.c. in 
three hours, although it did not appreciably affect 
the conductivity of the water. 
A CATALOGUE of periodicals and publications of 
literary and scientific societies, including standard sets 
and library editions, which they have on sale, has 
been published by Messrs. W. Heffer and Sons, Ltd. 
An inspection of the catalogue suggests that men of 
science and librarians have here a good opportunity 
of completing their sets of transactions and of making 
additions to their libraries at a moderate cost. 
A copy has been received from Cairo of the almanac 
for the year 1914 compiled in the Government Publica- 
tions Office for the Egyptian Government. The object 
of the almanac is to furnish information likely to be 
useful to the various Government administrations in 
their relations with each other and also to the general 
public. In the section concerned with the Ministry 
of Finance, full particulars are given in connection 
with the Survey Department; details as to schools and 
colleges are included under the heading, Ministry of 
Education; and an _ exhaustive section, entitled 
‘General Information,” supplies up-to-date facts as to 
rainfall and other meteorological data, magnetic 
values, scientific societies, weights and measures, in 
addition to other matters of importance. 
DETONATING FIREBALL OF JANUARY 19.—A consider- 
able number of records of this object have now been 
received by Mr. W. F. Denning, and it is certain that 
the fireball-descended io within a very small distance 
of the earth’s surface, if indeed it did not actually 
fall to the ground. The observations are not suffi- 
NO. 2312, VOL. 92] 
NATURE 
[FEBRUARY 19, I914 
ciently exact to indicate the precise spot where the 
meteor fell, if it came to earth, and the event might 
easily pass unnoticed if it occurred in a country place 
where no one happened to be near enough actually to 
witness it. : 
Several observers carefully timed the interval between 
the meteor’s brilliant flash and explosion and the 
sound which followed. This was half a minute near 
Oxford and one minute a little further off in the same 
part, while at several other places the times are given 
as one minute to five minutes, according to the vary- 
ing distance from the scene of the disruption. One 
minute’s interval equals a distance of about twelve 
miles, and as part of this was horizontal distance and 
not all vertical height, it is clear the fireball was only 
a very few miles high at the time of its final outburst. 
Inquiries should be instituted in the west part of 
Berkshire, near Lambourn, for it is possible evidence 
may be obtained as to the exact locality of the fall, if 
it occurred. The radiant of the meteor was south of 
Ursa Major, either at 132°+47°, or 154°+41° prob- 
ably. 
THE ToraL Sovar Eciipse or AuGusT 21 NEXT.— 
The Observatory for February publishes particulars 
of the provisional arrangements which have been made 
by the Joint Permanent Eclipse Committee with re- 
gard to the observations of the total solar eclipse of 
August 21 next. Under the auspices of the committee 
Prof. Fowler, Mr. W. E. Curtis, and Father Cortie, 
with Major Hills and Father O’Connor as volunteers, 
will be situated at or near Kiev. The first two-named, 
with Major Hills, will devote their attention to photo- 
graphing the spectrum of the chromosphere during 
the partial phases with iron arc comparisons. The 
other two will take photographs of the corona and its 
spectrum, chiefly in the region of longer wave-lengths. 
The Royal Observatory of Greenwich will be repre- 
sented by Mr. Jones and Mr. Davidson, who will 
attempt large-scale photographs of the corona, and 
its spectrum, with special reference to the ultra-violet 
region; they will be stationed at Minsk. The Solar 
Physics Observatory of Cambridge will send a party of 
three, namely, Prof. Newall, Messrs. Stratton and 
Butler, and this will be stationed at Feodosia, in the 
Crimea. Their programme will include direct photo- 
graphs of the corona on large and small scales, the 
former for studies of ‘‘arches,’” and the latter for 
extensions. |The chromospheric spectrum will be 
attacked with a concave grating without slit, for com- 
parison with the slit spectra of Prof. Fowler’s pro- 
gramme. Polariscopic observations will also be made. 
Tue Assorption oF Licut IN SPpAcE.—An ingenious 
method of trying to detect the absorption of light in 
space is that of photographing the spectra of stars 
which have similar spectra, but the stars themselves 
should be at very different distances from the earth. 
The spectrum of the more distant star should exhibit 
a greater absorption towards the violet than that of the 
nearer star, if such absorption be present in space. 
This method was proposed by Prof. Kapteyn, and a 
first attempt has been made by Mr. Walter S. Adams, 
using the Cassegrain spectrograph of the Mount Wil- 
son Solar Observatory; his results are printed in the 
current number of The Astrophysical Journal (January, 
vol. xxix., No. 1). The choice of stars was facilitated 
by the use of the ample material previously accumu- 
lated for line of sight work, and the pairs finally 
compared had spectra which were similar line for line. 
Stars of various spectrum types were employed, and 
of the twenty pairs investigated seven pairs were of 
class Ko, two from each of B8, Gs, and G6, and one 
from each of Ao, F4, F7, G8, K2, K4, and K6. While 
six pairs showed no appreciable difference between the 
