378 
NATURE 
[ FEBRUARY 18, 1904 
the catalogue number, the magnitude, the south polar 
distance, the C.P.D. number, and the exact precessional 
corrections for each star. 
THe CLIMATOLOGY OF 1903.—As in former years, the 
meteorologist of the Juvisy Observatory, M. J. Loisel, has 
published the detailed results of the observations made at 
that observatory during the past year in the Bulletin de la 
Société astronomique de France (February). 
The results are graphically depicted by a series of curves, 
one set of which shows and compares the rainfall, the direc- 
tion of the wind, the temperature, pressure and hygrometric 
state of the atmosphere, the number of hours of sunshine, 
the state of the sky, and the declination and phase of the 
moon for each day. A set of tables comparing each of the 
four seasons with the corresponding season for each year 
since 1886 shows that, on the whole, the winter was warm, 
the spring dry, the summer cold, and the autumn warm 
during 1903 as compared with the mean conditions. The 
curve depicting the amount of the effective insolation shows 
that during 1903 there were two maxima, one in May the 
other in July, instead of one in July as shown on the curve 
for 1902. A comparison of the total solar radiations 
observed during 1902 and 1903 gives 146,115 and 140,175 
calories respectively. 
MERIDIAN-CIRCLE OBSERVATIONS AT THE Lick OBSERV- 
Atory.—The results of the meridian-circle observations made 
at the Lick Observatory during the period August, 1896, 
to March, 1901, by Mr. Richard H. Tucker have just been 
published in one volume (Publications of the Lick Observ- 
atory, vol. vi., 1903). The results include about 11,700 
full observations, and 2700 observations in one coordinate 
only, for the determination of 4500 stars. 
The first part of the work consists of the results of the 
observations for declination of 361 latitude stars previously 
observed by Prof. Doolittle at South Bethlehem, Pa, and 
includes 107 stars from the ‘* Standard Catalogue ’’ of Lewis 
Boss. The resulting declinations are compared, where the 
stars are common to the catalogues, with those given in 
Boss’s catalogue and the Berliner Jahrbuch. 
The second part of the volume is devoted to the observ- 
ations of 21 circumpolar stars, all above declination + 82°, 
in compliance with a request of Dr. Auwers. Part iii. gives 
the results of the observations of 50 zodiacal stars, made 
during 1898 at the request of Sir David Gill to furnish 
places for his heliometer measures of the major planets. 
The volume also contains a description of the observ- 
ations, and their reduction and final results, of 3088 southern 
stars contained in the catalogue observed by Piazzi, at 
Palermo, during the period 1792 to 1813. ; 
The stars in the first and second lists of the Astrophoto- 
graphic Conference, of comparison stars for Eros, were 
observed at Lick, and the results are given and discussed 
in the fifth section of the volume. 
The observations are concluded with the results obtained 
in some miscellaneous observations made during the period 
1897 to 1901. These include 49 comparison stars for 
various purposes, 20 proper-motion stars observed for Prof. 
J. G. Porter, of Cincinnati, and several meridian-circle 
observations of Eres, Nova Persei, and two comets. 
M. BLONDLOT’S 2-RAY EXPERIMENTS.} 
N his experiments on the rapidity of propagation of the 
Rontgen rays, the French academician, M. R. Blondlot, 
discovered a new kind of rays, which he called n-rays, 
after the place Nancy, in which they were first observed.” 
These rays are said to be emitted by an Auer burner, or 
better still by a Nernst lamp of 200 watt power. Like the 
Réntgen rays, they are said to pass through aluminium 
with ease, but on the other hand to be absorbed by the 
slightest film of water, like the longer heat-waves. 
Although they are stated to be absorbed by cold platinum, 
they readily pierce red-hot platinum. 
1 Tyanslation of ** Notes in Elucidation of the Most Recent Researches 
of M. R. Blondlot on the #-Rays."" By O. Lummer. Read at the sitting 
of the German Physical Society, November 27, 1903. 
2 R. Blondlot, “* Sur de nouvelles actions produites par les rayons 7; 
généralisation des phénoménes précédemment observes” (C. R., Cxxxvii., 684, 
1903). “‘ Sur l’emmagasinement des rayons » par certains corps” (C. X., 
CNXXVI., 729, 1903). 
NO. 1790, VOL. 69] 
Blondlot has recently found that these n-rays are emitted 
by the wire of the Nernst lamp even after this has been 
extinguished fer several hours, and that, moreover, flints 
which have been exposed to the sun’s rays have a distinct 
effect in the sense of the n-rays. 
In all these observations of Blondlot the action of the 
n-rays consists in general of a brightening of a source of 
light under these rays, or rather of a darkening when the 
rays are cut off by interposing either the hand or a lead 
screen between the source of light and the source of the 
n-rays. The analysing source of light may be a smalk 
spark, a bluish flame, a phosphorescent surface, a dark 
platinum plate at dull red heat, or the surface of paper 
feebly illumined by a source of light. The dimensions of 
all these analysing sources of light are very small (the 
illumined paper, for instance, being 2 mm. by 16 mm. in 
size), and the observation is carried on in a dark room. 
Although the change in brightness is said to be con- 
siderable, neither Blondlot (C. R., cxxxvii., 167, 1903), 
Rubens (Ebenda) nor others (Phys. Zeitsch., iv., 732 and 
733, 1903) have hitherto succeeded in demonstrating 
objectively the corresponding transformation of energy. 
At the same time the phenomena observed subjectively 
by Blondlot could not be perceived by Rubens and others 
in repeating the latest experiments with slightly illuminated 
or phosphorescent surfaces. 
Without wishing, for the present, to dispute the objective 
existence of these n-rays, I should like in what follows to 
bring forward the fact that a whole set of Blondlot’s ex- 
periments may be almost exactly imitated in their effects 
without employing any source of illumination whatever, and 
that the changes in form, brightness, and colour respectively 
of the analysing luminous surface observed by Blondlot 
under a stream of rays, and the interception of a diaphragm 
(Abblendung) may be referred to processes taking place in 
the eye itself, and, in fact, to the contest between the rods 
and cones of the retina in seeing in the dark. 
It has been known for some time that the layer of rods 
and cones in the retina is the structure which is sensitive to 
light whereby this form of energy, from without, is trans- 
formed into nerve-stimulation. While, however, experiments 
on sharpness of vision have led to the assumption that the 
power of ion is due to the agency of the cones alone, 
the almost identical anatomical structure of the rods admits 
of the conclusion that they also play their part in vision. 
But on the ground of more recent physiological researches 
on vision in dim light, and the influence of the visual purple 
contained in the rods on colour-perception, we have been 
enabled to distinguish, more and more clearly, the re- 
spective modes of action of these two elements of the retina 
and to ascribe to them their different functions. A. Kénig * 
had already ascribed to the rods the colourless vision of the 
totally colour blind in every degree of brightness, the non- 
perception of colour in a very dim light of those otherwise 
able to perceive colours, and the perception of blue. J. v. 
Kries* went further, and disposed of the still existing 
difficulties and contradictions by putting forward the hypo- 
thesis that the cones form our colour-perceiving “‘ light 
apparatus’ (‘‘ Hellapparat ’’) and the rods our totally 
colour blind ‘‘dark apparatus”’ (“‘Dunkelapparat’’). Accord- 
ing to this theory of Kries the cones render vision possible . 
in a very bright light, and their stimulation by light-waves 
arouses in the brain the perception of colour, while the 
purple containing rods are totally colour blind, and only 
come into action in a very dim light, and are endowed with 
the property of considerably increasing their sensitiveness 
in the dark. These properties of the rods are called by 
Kries ‘‘ adaptability to the darkness ’’ (Dunkeladaptation). 
Before the cones perceive coloured light, the rods bring 
about in the brain the impressiqn of coiourless light. 
We know from the anatomy of the eye* that the fovea 
centralis contains cones only and no rods, and that the rest 
of the retina has rods as well as cones, the former pre- 
dominating towards the periphery, and it is also well known 
1 “ Uber den menschlichen Sehpurpur und seine Bedeutung beim Sehen 
(Sttsber. d. Berl. Akad d. Wissensch., S. 577, 1894)- 
2 Uber die Funktion der Netzhautstanchen (Zeétsch. f. Psych. u. 
Physiol. d. Sinnesorgane, ix., 81-123, 1894). 
8 R. Greef, ‘Die mikroskopische Anatomie des Sehnerven und der 
Netzhaut.’” Aus dem “‘ Handbuch der Augenheilkunde” von Graefe u- 
Samisch. 2 Aufl., I. Bd., V. Kap. (Berlin, 1901.) 
