Marcu 14, 1907] 
NATURE 
469 
heated up to red glow before being placed in the furnace. 
Primary currents of 50 or roo periods and 200 volts are 
used. When keeping the furnace at its maximum tempera- 
ture of 1300° C. for ten hours a day, about 2 lb. of 
barium chloride have to be replenished every day. The 
furnace lining is said to last about a year; the iron elec- 
trodes do not last so long. Barium chloride seems, so 
far, to be the best material fer the extreme temperatures. 
For lower temperatures mixtures of barium chloride and 
potassium chloride are used. The crust of fused salt 
which adheres to the steel peels off at once when the 
steel is dropped into the cooling liquid. Local super- 
heating is not to be feared in this kind of furnace, and 
the application of fused salts is attracting much attention. 
AN interesting discussion on the advantages and dis- 
advantages of heating buildings with gas stoves of various 
types, which was held at the meeting of the Royal 
Sanitary Institute on December 12 of last year, is printed 
in the March number of the Journal of the institute. Dr. 
Rideal, in opening the discussion, considered that as soot, 
carbon monoxide, and hydrogen sulphide are never present 
in the products of the combustion of coal gas in modern 
gas stoves, and as the proportion of oxygen in the air 
of a room is little changed when the heating is effected 
by a flueless gas stove, the use of flueless stoves was 
in several cases an advantage, especially when the economy 
of the heating effect was considered. The amount of carbon 
dioxide produced was not sufficient to be deleterious, and 
instead of causing defective ventilation, stoves, 
especially those of a condensing type, seemed actually to 
remedy it. Several speakers took part in the discussion, 
many of them dissenting from the views expressed by Dr. 
Rideal. In particular, the passage of sulphur acids into 
the air when a flueless stove is used appears to present 
difficulties. 
Messrs. JOHN J. GRIFFIN AND Sons, Lrtp., yesterday 
entertained a number of visitors at their new premises in 
Kingsway. New physical and other apparatus were ex- 
hibited, and there were demonstrations of the properties 
of vessels made of silica glass; of the oil-pigment process, 
velox printing, among modern processes in photography ; 
the wireless transmission of signals, the musical arc, and 
other physical phenomena. This opportunity of seeing 
instruments and processes in operation is likely to be 
appreciated by teachers and others, and Messrs. Griffin and 
Sons, Ltd., will probably be repaid for their enterprise. 
flueless 
OUR ASTRONOMICAL COLUMN. 
Discovery or A Comet (1907a).—A telegram from the 
Kiel Centralstelle announces the discovery of a new comet 
by Prof. Giacobini at the Nice Observatory. The object 
was of the eleventh magnitude, and its position at March 
gd. 1oh. ro.gm. (M.T. Nice) was 
Gh! 
R.A.=7h. 4m. 31-4s., dec.=18° 21! oe 
The daily motion is westward at the rate of 47’, and 
northward at the rate of 57’, per day. The above posi- 
tion lies in the constellation Canis Major, about 20’ E. 
and 13° S. of Sirius. . 
Sovak ResEarcH at Meupon.—In No. 5 (1907) of the 
Comptes rendus, MM. Deslandres and d’Azambuja de- 
scribe, and give some of the preliminary results of, the 
solar researches carried out at Meudon, with several forms 
of spectrographs, during the year 1906. One of the prin- 
cipal difficulties encountered by M. Deslandres in his 
previous experiments has been to obtain a_ satisfactory 
"NO. 1950, VOL. 75] 
slit so-narrow that’the finer dark lines of the spectrum 
might be completely isolated, and this dithculty was, to 
a great extent, overcome during the recent research by 
drawing a very fine clear line on the surface of a piece 
of chemically-silvered optical glass. By having a clear 
space above and below the slit, the solar spectrum was 
simultaneously photographed on each plate, thereby 
enabling the parallelism of the slit and the line, and the 
exactitude of the setting on the line, to be tested for each 
exposure. 
Photographs taken on the centres of the fine iron lines 
at A 4045 and A 4385 are found to differ considerably from 
those taken on the degraded edges of the lines, for whilst 
the latter show simply the bright faculic areas, the former 
show a net-work of bright inequalities of very different 
form; the photograph with the setting on the centre of 
the line is supposed to represent the upper layers of the 
iron vapours. The differences between the images obtained 
with the K, and K, lines are not so marked as was 
expected, although many of the bright areas obtained with 
the latter are not to be found on the K, images. No 
relation between the K, images and the dark calcium 
flocculi of Prof. Hale’s photographs could be established, 
nor could the similarity of the former with the dark areas 
produced by photographs on the dark hydrogen lines be 
recognised. 
THE Markincs AND Rotation PEertop OF VeENUS.—Mr. 
Denning, in continuing his series of articles on the planets 
in the March number (No. 381) of the Observatory, dis- 
cusses the contradictory results which have been derived 
from observations of Venus concerning the existence of 
permanent markings on the planet’s surface, and the time 
it takes the planet to perform one rotation on its axis. 
He points out that whilst Mr. Lowell records that he has 
seen the markings when their contours have ‘‘ had the 
look of a steel engraving,’’ numerous other very careful 
observers have failed to distinguish anything which might 
be recognised as permanent. Similarly, a large number 
of observers have arrived at the conclusion that the rota- 
tion period is about 23h.-24h., whilst others, including 
Schiaparelli, have concluded that it is about equal to the 
period of the planet’s revolution in its orbit. The spectro- 
scopic results are similarly in opposition. 
Summing up the results of the discussion, Mr. Denning 
concludes that after the earnest application of observers 
during three centuries. the problems of the configurations 
and of the axial rotation remain unsolved, the difficulties 
having, as yet, proved insuperable. 
Tue ELectTRIcaL INFLUENCE OF THE SuUN.—No. 8, vol. vii. 
(February 23), of the Revue Scientifique contains an 
interesting discussion, by Dr. A. Nodon, of the electrical 
influence of the sun on the earth. 
After giving a historical account of the subject, the 
author proceeds to describe the experimental results 
obtained by M. Brunhes and by himself, from which 
follows the deduction that the sun produces, at the earth’s 
surface, a positive electrical induction of variable magni- 
tude. The amount of this induction is far greater than 
that attributable to the actino-electric action of the 
luminous radiations, whilst the interposition of clouds 
before the sun arrests the induction effect. Other possible 
causes are discussed, and it is shown that, independently 
of these, there still remains an effective induction directly 
due to the sun’s charge alone. 
In a second part of the discussion, published in No. 9 
of the same journal, Dr. Nodon considers the effect of the 
solar influence on the planets, on comets, and on the 
earth in particular, and in conclusion he urges the funda- 
mental importance of the study of solar physics on the 
grounds that a large number of meteorological phenomena 
appear to be directly connected with the solar changes. 
REcENTLY DriscoveRED ASTEROIDS.—The provisional 
elements of the orbits of twenty-five recently discovered 
asteroids are published in No. 4156 (February 21) of the 
-Astronomische Nachrichten by Herr J. Bauschinger, of 
the Astron. Rechen-Institut, Berlin. These asteroids were 
discovered between August, 1905, and April, 1906, and 
their designatory numbers range from 570 to 508. 
