I Ss 
decrease in the resistance. 
thickness of one bar, the total resistance is the same 
FEBRUARY 5, 1914] 
another bar of identical length, shape, and size. The 
total resistance when the two bars are in contact is 
about three-quarters the resistance of one bar alone. 
As the gap is increased, there is at first a small 
With a gap equal to the 
as when the bars are in contact, and becomes equal 
to the resistance of one bar alone when the gap is 
twice the thickness of one bar. With a gap of six- 
teen times the thickness, the total resistance is only 
5 per cent. less than double the resistance of the 
single bar. It would appear from these experiments 
that the total resistance of struts, following in the 
same run of air and more than thirty times the 
thickness apart, may be assumed to be the same as 
the total resistance of the separate struts in a clear run 
of air. 
Tue Vesterling Organisation Company, Clapham 
Junction, London, S.W., manufactures a convenient 
loose-leaf book, which has certain novel characteristics. 
By the use of a patent device in the back of the 
book it opens flat at any place. Specially made rings 
render the filing of new papers, or removal of old, 
simple and quick. The book will prove of real assist- 
ance to lecturers who use copious notes, and to all 
who have to preserve loose papers in a way which 
makes ready reference easy. 
A 1914 supplement to their ‘General Apparatus 
Catalogue, 1910,”’ has been issued by Messrs. Heynes 
Mathew, Ltd., of Cape Town. The new list of appa- 
ratus affords an instructive illustration of recent pro- 
gress in South African education. The improved 
methods of teaching geography which have become 
_established in this country, for example, are being 
taken up in South African schools, and a demand for 
material for lessons in practical geography is met by 
a section in the new catalogue being devoted to this 
subject. Similarly this firm is prepared to supply 
equipment for practical work in botany and other 
branches of science. 
OUR ASTRONOMICAL COLUMN. 
PLANETARY OBSERVATIONS AT THE LOWELL OpsERvA- 
vory.—In Astronomische Nachrichten, No. 4710, a 
telegram is published from Prof. Lowell relating to 
observations on the satellites of Saturn and on 
Martian features. With regard to the former it is 
stated, “‘Tethys and Dione variable, range quarter 
magnitudes, periods coincident with revolution.” Re- 
lating to the latter, the telegram says :—‘ The full 
aperture of the 4o-in. reflector of the Lowell Observa- 
tory only now equipped for visible work shows the 
canals of Mars as fine direct geometrical lines, thus 
corroborating the work of smaller apertures. This 
should dispose of the erroneous idea that [such] 
apertures do not disclose these remarkable features.” 
Wave-LENGTHS oF CHROMOSPHERIC Lines.—It was 
known soon after the event of the total solar eclipse 
of August 30, 1905, that Prof. S. A. Mitchell, who 
was in charge of the numerous spectroscopic instru- 
ments which were employed in the United States 
Naval Observatory eclipse expedition, had secured 
some most excellent photographs of the spectrum of 
the chromosphere. It is not until now, however, that 
NO. 2310, VOL. 92] 
NATURE 
643 
the results of their reduction are published, and these 
are printed in the current number of The Astrophysical 
Journal (December 1913). The photographs discussed 
were secured with gratings, both parabolic and plane, 
and the present paper deals with the reduction of one 
photograph from each instrument for the purpose of 
giving chromospheric wave-lengths, intensities, &c., 
“with as great an accuracy as possible.’’ This com- 
munication is finely illustrated with plates showing 
different portions of the photographs, and they are 
demonstrative of the very fine adjustment of the in- 
strument during use. A very long table shows the 
wave-lengths compared with Rowland, and the heights 
of the chromospheric lines, the corresponding elements 
and intensities according to Rowland, chromosphere, 
arc, and spark. No fewer than 2841 lines are tabu- 
lated in the chromospheric spectrum, and this above 
many faint lines which were measured; no lines were 
included unless they were measured in two or more 
separate measurements. The paper is full of many 
interesting summaries of these chromospheric lines 
arranged according to elements, atomic weights, &c. 
The conclusions arrived at are important, but it is im- 
possible to repeat them all here. Some of them are as 
follows :—The ‘ flash”? spectrum is a reversal of the 
Fraunhofer spectrum. The “flash” is not an instan- 
taneous appearance, but the chromospheric lines 
appear gradually, the highest layers first, the lowest 
last. The ‘‘reversing layer,’ which contains the 
majority of the low-level lines of the chromosphere, is 
about 600 km. in height. Wave-lengths in chromo- 
spheric and solar spectra are practically identical, 
the chromospheric spectrum differing greatly from the 
solar spectrum in the intensities of the lines. The 
differences of intensity find a ready explanation in the 
heights to which the vapours ascend. The enhanced 
lines are especially prominent in the chromosphere, 
and these are said to become brighter mainly because 
at the heights to which they ascend the vapours are 
mixed with hydrogen at reduced pressure. 
Tue ANNUAL OF THE Bureau pes LoncitupEs.—The 
annual published by the Bureau des Longitudes is 
familiar to all readers of this column, and the present 
issue for 1914 will no doubt be found as useful for 
reference as its predecessors. In addition to the usual 
astronomical, physical, and chemical data embodied 
in these small pages, will be found articles of astro- 
nomical interest. “Thus M. Deslandres gives a résumé 
of solar physics, M. P. Hatt contributes a_ short 
article on the deformation of images in telescopes, 
while M. G. Bigourdan writes very fully on the day 
and its subdivisions, the hour-zones and the inter- 
national association of the hour. The seventeenth 
meeting of the International Geodetic Association is 
described by M. B. Baillaud. 
WHAT IS PSYCHO-ANALYSIS? 
ERHAPS the most important and _ startling 
scientific theory of modern times is that which 
Prof. Sigmund Freud, of Vienna, has formed to 
explain the workings of the human mind. Many 
thinkers, indeed, hail Freud as the Darwin of the 
mind, and consider that his views are destined to 
transform the science of psychology. He certainly 
has succeeded in explaining such obscure and widely 
differing phenomena as dreams, wit, the seemingly 
accidental mistakes in speaking and writing which 
people so often make, the obsessions and _ other 
symptoms found in a large class of mental diseases, 
and the spontaneous likes and dislikes which we all 
experience and find so puzzling, in terms of one single 
hypothesis. Put guite briefly, this is the hypothesis 
of ‘the unconscious mind,"’ something quite distinct 
