232 
NATURE 
. 
[NovEMBER 23, 1916 
Slipher, the spectra in this case indicating rota- 
tion in 10h. 50m., in a direction contrary to that of 
the planets nearer the sun. Much attention was at 
one time given to the search for evidence of ab- 
sorption due to water vapour in the atmosphere 
of Mars, first by Doppler effects due to relative 
motion of the earth and planet, and alternatively 
by observations of the relative intensities of the 
atmospheric bands in Mars and the moon. AIl- 
though measurements of the plates suggested 
slight displacements, tending to prove the exist- 
ence of a Martian atmosphere, Lowell frankly con- 
fessed that he could place no reliance on this 
result. On the other hand, Mr. Very’s discussion 
of the intensities of the bands decided in favour 
of a Martian atmosphere containing water vapour, 
but this conclusion was not accepted by Campbell. 
A further notable contribution to the spectro- 
scopic study of planets was made by a beautiful 
series of photographs of the spectra of the major 
planets, showing the progressive increase of in- 
tensity of the characteristic planetary absorption 
bands in passing from Jupiter to Neptune. No 
satisfactory interpretation of these bands has yet 
been given, but the photographs provide very 
definite data for guidance in experimental research 
relating to them. 
The spectroscopic investigations of comets 
undertaken at Flagstaff have been of more 
than ordinary interest in consequence of their 
inclusion of the red part of the spectrum, of 
which but little was previously known. Much 
remains to be done in connection with the inter- 
pretation of these observations, and in order to 
facilitate this work Lowell very generously placed 
copies of the photographs at the disposal of those 
who were in a position to undertake the necessary 
experiments. One important result obtained by 
Lowell, following from simultaneous photographs 
of the forms and ‘spectra of comets, was that 
gaseous masses could in some cases be proved to 
be moving away from the head. This point de- 
serves more attention than it has received. As 
Lowell put it: ‘‘As the incompetency of light- 
pressure to repel molecules in a comet’s tail has 
been widely published, this observational proof 
that molecules in such a tail are repelled—whether 
they can be or not theoretically—is of considerable 
interest.” 
Spectroscopic investigations of the spiral nebule 
are extremely difficult and laborious on account of 
the feeble luminosity, but the Flagstaff observers 
provided themselves with well-designed instru- 
ments and boldly attempted to determine the radial 
velocity of one of these objects. In the first in- 
stance, the Andromeda nebula was found to be 
approaching the solar system with a velocity of 
300 km., per sec., and the suspicion that spirals 
as a class have much higher velocities than stars 
has since been abundantly confirmed. The nebula 
N.G.C. 4594 was, in fact, afterwards found to 
be not only receding at the immense speed of 
1100 km. per sec., but also to have a motion of 
rotation such that at a distance of 20” from the 
nucleus the velocity is 100 km. per sec. These 
NO. 2456, VoL. 98] 
results are clearly of fundamental importance, and 
would seem to favour the view that the spiral 
_nebulz are to be regarded ag stellar systems out- 
side that to which the sun belongs. ; 
Another difficult investigation undertaken at 
llagstaff was that of the constitution of the ex- 
tremely faint nebule surrounding the stars of the 
Pleiades. It was found that the characteristic 
lines of gaseous nebule were absent, and that the 
spectrum was identical with. that of the associated 
stars, leading to the conclusion that the nebula 
shines by reflected starlight. A similar conclusion 
has since been reached from an investigation of 
the nebula about p Ophiuchi. 
Those who have had the privilege of a visit to 
the Lowell Observatory cannot fail to have been 
impressed by the ample provision for a wide range 
of astronomical inquiries, and by the fine display of 
transparencies representative of the successful’ 
results which have rewarded the skill and patience 
of the observers. The inspiring enthusiasm of 
Lowell will doubtless be sadly missed in the future, 
but it is sincerely to be hoped that some means 
will be provided whereby the activity of the ob- 
servatory may be maintained. A. FOWLER. 
NOTES. 
Unper the new regulations recently made with a 
view to the control of food supplies, the Board of 
Trade issued on Monday the following Order as to the 
milling of flour:—The Milling Order, 1916, fixes for 
the United Kingdom the percentages of flour that 
must be extracted from wheat of various qualities 
according to the following schedule :—English, 76; 
Choice Bombay, 78; Australian, 78; Blue Stem, 76; 
Walla Walla, 75; No. 2 Red Western, 76; No. 2 Red 
Winter, 74; No. 2 New Hard Winter (1916), 76; 
No. 1 Northern Duluth, 75; No. 1 Northern Manitoba 
Old Crop, 76; No. 2 Northern Manitoba Old Crop, 75; 
No. 3 Northern Manitoba Old Crop, 73; Choice White 
Karachi, 75; Soft Red Karachi, 75; Rosafe, 62 Ib., 
73; Baril, 614 lb., 74; Barletta-Russo, 613 Ib., 74. 
The Order comes into force, as regards milling, on 
November 27 next; that is to say, on and after that 
date no wheat may be milled except in accordance 
with this schedule. On and after January 1, 1917, 
only flour milled in accordance with the schedule may 
be used for making bread or any other article of food. 
A subsequent Order will be issued requiring periodical 
returns of stocks of wheat received and of flour and 
offals milled and of all stocks in hand on the date of 
the Milling Order coming into operation—i.e, Novem- 
ber? 27; 
Tue statistics given in the half-yearly Review of 
the Movement of Fertilisers and Chemical Products 
just issued by the International Institute of Agricul- 
ture show very clearly the effects of the war on this 
branch of industry. Shipments of natural phosphates 
are diminishing both on account of the scarcity of 
labour and the high rates of freight. As regards 
superphosphate of lime, the small. supply of raw 
phosphates and. the ever-increasing demand for sul- 
phuric acid for munitions of war have depressed the 
output in all countries, notably in France, where the 
latest figures show a decrease of 50 per cent. on the 
production of 1913. The increase in the exports of 
Chilean nitrate, which began in the latter half of last 
year, has continued, so that the figures are now much 
