404 
. NATURE 
[ Feb. 22, 1883 
mica-disc be introduced into the luminous ray, it enters 
into oscillation; and a small mill is set in rotation by the ray. 
This proves that real material particles, glowing masses of gas, 
‘are driven forth in the discharge from the tube. The wall on 
which the ray impinges is strongly warmed, and a thermometer 
put into the ray rises 10° to 20°. _If the ray, which to the naked 
eye seems quite continuous, be looked at through a slit in a 
rotating disc, so arranged that the slit, in different, very short 
intervals of time after each opening of the primary current of 
the induction-coil, passes before the eye, one sees in the first 
moment a small ray at the opening, then, at a later moment, 
a small cloud above the opening, and finally a larger luminous 
cloud floating at a greater distance from theopening. The light- 
ray is thus discontinuous ; and at each spark-discharge separate 
clouds of glowing gases are driven out from the tube, which are 
ever enlarging. Evenat atmospheric pressure these light-pheno- 
mena may, with careful observation, be perceived. They occur 
mostly in the air as yellow sheaths about the aureoles of the 
sparks, and with different electrodes present manifold forms : 
sheaths, swellings, whirls, and the like, In moist airthe phenomenon 
is quite absent, and in hydrogen it soon ceases. The great variety 
of the appearances have not yet been brought under one common 
standpoint.—Dr. Goldstein had observed similar phenomena to 
those just described by Dr. Hertz, and made a number of experi- 
ments regarding them. In spectral tubes he saw the yellow 
light appear at the places of passage from the thin to the wider 
parts, in cylindrical tubes, on the other hand, the yellow light 
always surrounded the red discharge-light as an envelope, which in 
the neighbourhood of the cathode gradually widened, and from 
there progressively filled the tube. If evacuation be effected 
during the discharge, one sees that the yellow light, with the air, 
is driven out of the tube. This glowing of the gas Dr. Goldstein 
connects with the long-known after-luminosity of Geissler tubes, 
which he has sometimes found to last many seconds, and even 
some minutes, after discharge. The essential thing in the case 
of phosphorescent Geissler tubes is the change between wider 
and narrower parts, because only at the places of transition does 
the after-luminosity develop that light—yellow in air, blue in 
hydrogen, and other colours in other gases. 
PARIS 
Academy of Sciences, February 12.—M. Blanchard in the 
chair.—The following papers were read :—On the difference of 
barometric pressures at two points of a given vertical, by M. 
Jamin. He shows from records of the double observatory at 
the base and at the top of the Puy de Déme, for 1880, that the 
difference of pressures varies very regularly every day and 
throughout the year, diminishing till 3 p.m., then increasing till 
sunrise, also increasing from the summer to the winter solstice. 
Kaemitz, in 1832, proved such variation with the season in 
Switzerland. Similar effects, due to temperature, duubtless 
occur everywhere. We have to conceive an atmospheric en- 
largement, a kind of air-tide, moving round with the sun, The 
resulting phenomena are complex. M. Jamin shows how the 
variations of the difference of pressures in a given vertical, with 
changes of temperature, pressure, and hygrometric state, may be 
calculated.—Researches on chromates, by M. Berthelot.—On 
the grou, ings of the animal world in primary times (second note), 
by M. Gaudry. Each of the epochs seems to have had special 
expansions, beings that began with it and ended withit. The 
irregularities met with do not favour the idea of a struggle for 
life in which the victory was to the strongest and best-endowed. 
There are many striking personalities, vois de passage (so to 
speak), giving the epochs a character of their own, so that as we 
speak of the age of Charlemagne, &c., we may say the age of 
Paradoxides, of Pterichthys, &c. But it is often the most 
specialised and perfect beings that have disappeared. Other 
types, representing the just mean, have persisted.—On the 
numbers of unequal ordinary fractions which may be expressed 
by using figures which do not exceed a given number, by Mr. 
Sylvester.—Refutation of a second critique by M. Zeuner, &c. 
(continued), by M. Hirn.—Researches on the 7é/e of inhibition 
in’a special kind of sudden death, and with regard to the loss of 
consciousness inepilepsy, by M. Brown-Séquard. The losses of 
function and activity of the brain, in certain cases, are pure 
effects of inhibition, arising from irritation more or less distant. 
—lInfluence of subterranean humidity and of capillarity of the 
soil on the vegetation of vines, by M. Barral. The fruitfulness 
of the vine on the sandy soil of Aigues-Mortes is due to abun- 
dant water in the subsoil (from 1 m. depth) rising to the roots by 
capillarity. The author describes several laboratory experiments, - 
—On treatment of the vine with sulphur in Greece, by M. 
Gennadius. This treatment (for oidium) is thought successful 
only if carried out on a day without wind, rain, or clouds, and 
with a burning sun. This fine weather must last twenty-four 
hours. It is the sulphurous vapour, and not the sulphur 
powder, that kills the spores in the air and on the vine, though 
the powder may act mechanically (and other fine powders will 
do the same) by protecting tender parts from contact with spores. — 
On germinated wheat, by M. Ballard. The gluten is profoundly 
altered ; there is more acidity and more sugar and lignin ; less 
fatty matter—On the relations that exist between covariants and 
invariants of binary forms, by M. Perrin.—On the theory and 
experiments of MM. Mercadier and Vaschy tending to establish 
the non-influence of the di-electric on electro-dynamic actions, 
by M, Lévy.—General method for strengthening telephonic 
currents, by Mr. Moser. He introduces more induced coils.— 
On chlorides of lead and of ammonia, and oxychlorides of 
lead, by M. André.—Preparation of ethers of trichloracetic acid, 
by M. Clermont,—Contribution to the study of isomerism in the 
pyridic series, by M. Gichsner de Coninck.—On the relative 
toxical power of metallic salts, by Mr. Blake. His tabulated 
data of experiments show why he cannot accept the law formu- 
lated by M. Rabuteau (that metals are more active the greater 
their atomic weight and the smaller their specific heat).—Pene- 
tration of actinic radiations into the eye of man and of vertebrate 
animals, by M. de Chardonnet. He finds that no medium of 
the eye is transparent for the ultra-solar radiations, that is, for 
waves shorter than T or U, the limits of the ultra-violet solar 
spectrum. The mitilating membrane in sparrow-hawks and 
fowls is translucid for part of the ultra-violet spectrum (up to 
O and Q). The absorbing power of the vitreous humour, 
cornea, and crystalline lens varies in different species. The 
general fluorescence corresponds to actinic absorption, but 
there are exceptions.—New researches on the production of 
monsters in the hen’s egg by the effect of late incubation, 
by M. Dareste. This takes place more slowly in winter than 
in summer. Also eggs of the same age grow old more or 
less quickly. —On the tonic and inhibitory 7é/e of the sympa- 
thetic ganglions, and their relation to vaso-motor nerves, by 
MM. Dastre and Morat.—The mode of fixation of the 
suckers of the leech studied by the graphic method, by M. 
Carlet. The movements of the animal on smoked paper were 
observed. It has been received that the oval sucker is attached 
first by the centre, then by the borders, but the author finds 
that the borders are fixed first. Detachment, too (which does 
not seem to have attracted attention), begins at the borders.— 
On a new fixed Crinoid, Democrinus parfaiti, obtained in 
dredging from the Zravailleur, by M. Perrier. This makes 
only the fifteenth species known. It is distinguished by a long 
funnel-like cup, formed of five basal pieces.—Geological and 
chemical researches on the saliferous formations of the Swiss 
Alps, and especially on that of Bex, by M. Dieulafait. These 
beds the author regards as products of evaporation of ancient 
seas. 
CONTENTS PAGE 
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LxeTTERS TO THE EprTroR:— 
Hovering of Birds.—THe Duke or ArGytt, F.R.S.; Huperr 
385 
386 
IATRY. EDENRY CREIE Seis, oy is) reece ne ike fn ni fo” eto esi mIOY) 
The Auroral Meteoric Phenomena of November 17, 1882 —Dr. 
H.. J. Hi(GRoneMAN o,f. 5 ta ie) jn le Un! ©) ce ongeD 
The Orbit of the Great Comet of 1882—E. RisToRI . « - « 388 
Aino Ethnology.—A. H. KEANE . . . . - + «© © «© @ « 389 
Auroral Experiments in Finland.—S. LemstriM . «. « s « 389 
Flamingoes and Cariamas.—JAMES CURRIE . - « « + « « «= 389 
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Tue Procress oF TELEGRAPHY - . - - « «© « + © + © « «© # 390 
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NOTES si-len eles wens = [rath al. <wt=, Dale) Wale Res’ <iie ate eenaeaOs: 
Our AsTRONOMICAL COLUMN:— 
The Great Comet of r882. . 2. «© - - © © © © © « «© © = 400 
Variable Stars er a Ses cu ere rar. ie 
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