120 
NATURE 
[ Mov. 25, 1869 
chloride before subjecting them to heat, the au hor ascertained 
that chlorine was the only gaseous product of thi decomposition. 
The black compound invariably contained mor or less of the 
liquid chloride which had escaped decomposit on; the greater 
part of this was easily expelled on gently heatin the mass after 
opening the tube. In order to free it completely from the latter 
body the black substance was transferred to a clean tube, and 
heated to 120°C. (7.2. about 2° above the boiling point of chromyl 
dichloride) in a current of dry carbonic acid gas until its weight 
appeared constant. A determination of the amount of chlorine 
contained in the volatile portion showed that it was simply 
chromyl dichloride which remained undecomposed. ‘The solid 
substance, dried in the manner above described, appeared as a 
black uncrystalline powder, which, when exposed to the air, 
rapidly deliquesced to a dark reddish brown syrupy liquid, smell- 
ing of free chlorine. When thrown into water it quickly dis- 
solved, forming a dark brown solution, which, on standing, also 
evolyed chlorine. In nitric acid solution hypochlorous acid ap- 
peared to be produced. In strong hydrochloric acid the substance 
dissolved with a dark brown colouration, and on boiling the 
solution chlorine was evolved, the liquid became greenish yellow, 
and ultimately changed to the dark green colour, peculiar to a 
solution of chromium sesquioxide in hydrochloric acid. When 
thrown into dilute ammonia, chromic acid was dissolved, together 
with all the chlorine, and a precipitate was formed, possessing 
the properties of the chromate of chrome sesquioxide (Cr,O,CrO3) 
described by Storer and Eliot. Upon this decomposition is 
based the method which the author employed for the estimation 
of the amount of chlorine contained in this body. ‘The weighed 
quantity of the substance was treated with very dilute ammonia, 
the solution boiled for a few minutes, filtered, the precipitate well 
washed by hot water, an excess of nitric acid added to the filtrate, 
and the chlorine precipitated by the addition of silver nitrate. 
Two determinations of chlorine, carried out in this manner on pre- 
parations made at different times, gave 21°06 per cent. of chlorine 
as the mean. In order to determine the amount of chromium, 
a weighed portion of the substance was repeatedly heated with 
strong hydrochloric acid on a water-bath until the evolution of 
chlorine entirely ceased; the solution was then diluted with 
water, heated to boiling, ammonia added in slight excess, and 
again boiled until the supernatant liquid appeared perfectly 
colourless. The precipitated chrome sesquioxide was then filtered, 
dried, and weighed. The mean of two determinations indicated 
48:91 per cent. of chromium. These results come very near to 
the percentage composition calculated for the empirical formula 
Cr,0,Cl,. In conformity with the analytical results, the new 
oxychloride may be regarded as a compound of chromous chloride 
with two equivalents of chromium trioxide, and represented by 
the formula CrCl,2CrO;, analogous to the formulz assigned by 
Péligot to a series of chlorochromates. Experiment, however, 
led the author to believe that the constitution of his chromium 
chlorochromate, and of the salts described by Péligot, is not 
correctly represented by such formulz, and in his paper he gives 
elaborate structural formule, which seem to him to agree better 
with experimental facts, and to show the relation of these com- 
pounds to chromy] dichloride. 
Paris. 
Academy of Sciences, November 15.—M. E. Becquerel 
communicated the fifth memoir of his researches upon the 
luminous effects resulting from the action of light upon bodies, 
containing his investigation of the influence of the waves of 
light of different refrangibilities. His paper, which is of the 
greatest interest and importance to physicists, describes his ex- 
periments upon the behaviour of a number of phosphorescent 
bodies in various parts of the spectrum. No idea of its contents 
could be given in a short abstract, but we shall probably revert 
to it on another occasion.—In a note on “The Explosions of 
Bolides and the Falls of Aerolites which accompany them,” M. 
Delaunay suggested that the explosion of a bolide is caused by 
the pressure of the atmosphere in front of it taking advantage of any 
irregularities in the structure of the body, the latter being pro- 
bably, in many cases, caused or increased by the influence of the 
great superficial heat. The same atmospheric pressure, in M. 
Delaunay’s opinion, stops the onward motion of the detached 
fragments, which then fall to the ground. The black crust of 
the surface of aerolites was ascribed by the author to the passage 
of the fragments at the moment of their being detached through 
the compressed and heated air. General Morin remarked upon 
the compression of the air in front of projectiles and below fall- 
ing bodies. —M. Chapelas presented a note on the meteors of 
November 1869, in which he stated that on the 12th and 13th 
of this month the number of meteors observed was—on the 12th, 
6°8, and on the 13th 24°8, per hour, The maximum occurred 
in the early part of the night.—A notice of the partial explosion 
of a bolide by M. J. Silbermann was communicated. This meteor 
was observed on the 11th November, at 10°55 p.m., in the con- 
stellation of Ursa Major. It descended obliquely towards the 
horizon N.N.E. of Paris, and passed through a space of about 
34°. Its trajectory, at first nearly straight, soon became undu- 
lated between the stars y and w, Urse Aajoris; its rapidity of 
moyement diminished considerably, and a violent explosion took 
place, the apparent volume and _ brilliancy of the body having 
previously increased greatly. After the explosion it continued 
in a straight course for some distance. The explosion was very 
brilliant, and sparks were scattered in all directions. The author 
concluded that this explosion was only partial. M. H. Lar- 
tigues, who also observed this meteor, spoke of it as having dis- 
appeared after dividing into fifteen or twenty fragments. He 
described some of these as coloured, which was denied by M. 
Silbermann ; and the latter gives the meteor a duration of at 
most I$ seconds, whilst according to M. Lartigues it was visible 
for four seconds. —M. H. Sainte-Claire Deville presented the cor- 
rection of an error in the formule for calculating the co-efficients 
of dilatation insome of his memoirs. —M. E. J. Maumené communi- 
cated some facts observed with regard to inverted sugar. Theauthor 
stated that inverted sugar consists not of equal quantities of 
glucose and levulose, as supposed by Dubrunfaut, but of 12°14 
of the former and 87°86 of the latter. Crystals of glucosate of 
sodium-chloride obtained from inverted sugar, presented the same 
composition and primitive crystalline form as crystals obtained 
from diabetic sugar, but their solution effected what M. Maumené 
calls the deversion of the rotatory power in an hour and 
three-quarters, whilst the solution of the same compound prepared 
from diabetic sugar requires seven hours to produce the same 
effect. The author also remarked upon some other points 
connected with inverted sugar and the glucosate of sodium 
chloride. —Of two geological papers presented to the meet- 
ing, the first was by Mr. Gaston Planté on ‘‘The Lower 
Lignites of the Plastic Clay of the Paris Basin.” The author 
described a section near Meudon, where the lower lignite beds 
had been exposed. It showed in descending order—(1) the 
lower beds of the Calcaire grossier; (2) a bed of plastic clay 
with a black lignitiferous vein (the upper lignite bed) ; (3) a red 
marbled clay bed; (4) a dark clay bed containing lignites (the 
lower lignite bed); and (5) conglomerate. The lower lignite 
beds furnished parts of the lower jaw of Crocodilus depressifrons 
(Blaino), and a femur belonging to the same species; two verte- 
bree, probably of Coryphodon ; and the lower extremity of a bone, 
probably the humerus of a mammal, having the whole of the 
osseous tissue converted into gypsum in small crystals. The bed 
contained numerous coprolites of crocodiles. The subjacent 
conglomerate furnished numerous fossils, including teeth and 
fragments of crocodiles and mammals, portions of tortoises, and 
scales of Lefidosteus. The teeth of mammalia appear to indicate 
the genera Coryphodon, Pal@onictis, and Pachynolopyus.—The 
second geological paper was. by M. E. Guignet, and treated of 
the chemical composition and formation of the beds of the 
great oolite and forest marble of the Haute Mame. The author 
discussed the distribution of these formations and the influence 
exerted by their presence upon agriculture. —M. Croullerois pre- 
sented a note on a ‘‘ Theorem of Electro-Dynamics and the 
Explanation of an Electrical Phenomenon ;” and M. Milne Ed- 
wards four notes on some zoological observations made in his 
laboratory at the Museum.—In the first of these, M. Jobert 
described the structure and anatomical relations of the nasal 
glands in birds ; the second, by M. Oustalet, contained a minute 
description of the respiratory organs in the pupee of dragon-flies; 
the third consisted of observations on the salivary glands of 
Myrmecophaga tamandu, by M. J. Chatin; and the fourth was 
an anatomical and zoological investigation of the species of the 
genus Zguus allied to the Hemione, by M. George.—A letter 
from Mr, A. Mayer, accompanying his photographs of the late total 
eclipse of the sun, was communicated by M. Delaunay.—M. E. 
Mathieu presented a memoir on the equation with partial dif- 
ferences of the fourth order A A u=o, and on the equilibrium 
of elasticity of a solid body.—A portion of a letter from M. E. 
Duclaux was read, in which he announced that by exposing the 
eggs of silkworms to cold in August, he had caused an early 
development of the embryos, which were hatched in Noyember. 
