Nov. 4, 1869| 
NATURE 
27 
prospectus of a biography of this illustrious man of science, 
which he intends to publish. Forty new members were admitted. 
Prof. Zollner continued his lecture on his observations of 
the solar protuberances, and on a method of ascertaining the 
moyements of celestial bodies by means of spectral analysis. 
His views were discussed by MM. Oppolzer, Scheibner, and 
Struve. A number of proof-prints of Prof. Heis’ (Minster) 
stellar maps were committed to MM. Julius Schmidt and Prof. 
Galle, to report upon. M. de Littrow, sup2rintendent of the 
Vienna University Observatory, communicated and explained the 
plan of the} new Observatory to be built there, and commented 
upon the recent endeayours of some calculators of the solar 
parallax to derive ‘useful results }from Father Hell’s observa- 
tions, dating from 1769, proving these attempts to be altogether 
useless, by exhibiting the original diaries of this observer, and 
distributing fac-similes of the most important passages of them. 
A communication, concerning the establishment of a Humboldt 
Foundation at Vienna, was read. 
September 16.—The president and council were elected ; 
M. Struve, President; Prof. Bruhns, Vice-President; MM. 
Auwers and Winnecke, secretaries; Prof. Zollner, Librarian ; 
M. Auerbach, Treasurer; MM. Argelander and de Littrow, 
members of the Council. A new member was admitted. 
Mr. Julius Schmidt read his report on Prof. Heis’s stellar maps. 
Prof. Forster read a paper concerning the solar eclipse of August 
18, 1868, with Dr. Tieb’s remarks on the photograms of it, 
taken at Aden, and proposed that the President and Council 
should ensure their assistance on the occasion of the next transit of 
Venus to any astronomers who should apply for it. The motion 
has been adopted. Dr. Kaiser gave an account of his observations 
concerning the ellipsoidal form of the Moon, and the solar 
protuberances, which elicited a reply from Prof. Zollner, 
M. de Littrow communicated the first report of the permanent 
Adriatic Commission, and the programme of the prizes for the 
discovery of comets, lately proposed by the Imperial Academy 
of Vienna. Prof. Schonfeld exhibited a letter from Fabricius to 
Tycho Brahe (1596), in which the first notice of Mira Ceti is 
given, and entered into historical details concerning this variable 
star. The session of 1869 was closed by thanks voted to the 
Imperial Academy for having placed suitable localities at the 
disposal of the Society. 
CHEMISTRY 
Preparation of Uranium 
M. PeLicot has communicated to the Annales de Chimie et 
de Physique [xvii. 368] a short note on the preparation of 
uranium. A mixture of 75 grammes of uranous chloride, 150 
grammes of dry potassium chloride, and 50 grammes of sodium in 
fragments, is introduced into a porcelain crucible, itself surrounded 
by a plumbago crucible. The reaction is effected in a wind 
furnace, at the temperature of redness ; but the heat must be 
increased for a short time at the close of the operation. In the 
black slag may be found, after cooling, globules of fused uranium. 
Throughout the operation, it is necessary to avoid the presence 
both of moisture and atmospheric air. 
A specimen of the metal prepared in this way by M. Valen- 
ciennes had the specific gravity, 18°33. Uranium, is, therefore, 
one of the densest of metals. 
Stannous Chloride and Acids of Arsenic 
A, BETTENDORFF has examined the action of stannous chloride 
on the oxygen acids of arsenic. When a solution of stannous 
chloride in fuming hydrochloric acid is added to a solution of 
arsenious or arsenic oxide in the same acid, a brown precipitate 
is formed, which, after proper washing and drying, consists of 
metallic arsenic mixed with a small quantity of stannic oxide. 
In an aqueous solution of arsenious or arsenic acid, stannous 
chloride produces no precipitate ; but on adding strong hydro- 
chloric acid till the liquid fumes slightly, precipitation takes 
place. Arseniferous hydrochloric acid of sp. gr. 1°182 to 1°135 
gives an immediate precipitate ; the same diluted to sp. gr. 1°115 
gives imperfect precipitation after some time ; and in a similar 
solution of sp. gr. 1'100, no precipitation takes place. From 
this it may be inferred that the reaction occurs only between 
stannous chloride and arsenious chloride ; further, that in a solu- 
tion of arsenious acid in hydrochloric acid of sp. gr. I°115 part 
of the arsenic is present as chloride, but that hydrochloric acid 
of sp. gr. I°100 dissolves arsenious acid as such, without convert- 
ing it into chloride. The reaction above described is extremely 
delicate, and capable of detecting 1 pt. of arsenic in a million 
parts of solution. On antimony compounds stannous chloride 
exerts no reducing action, even after prolonged heating : hence 
the above-described reaction may be used to detect the presence 
of arsenic in antimony compounds, the solution being previously 
saturated with hydrochloric acid gas. Another useful applica- 
tion of the same reaction is to the preparation of hydrochloric 
acid free from arsenic: 421 grms. of crude hydrochloric acid of sp. 
gr. 1°164 were mixed with a fuming solution of stannous chloride, 
the precipitate separated by filtration after twenty-four hours, 
and the hydrochloric acid distilled, the receiver being changed 
after the first tenth had’passed over, and the remaining liquid 
distilled nearly to dryness. The acid thus obtained gave not the 
slightest indications of -arsenic, either by Marsh’s test or by 
precipitation with hydrogen sulphide.—{Zeitschr. f. Chem. (2), 
v. 492.] i 
Dichlorinated Aldehyde 
PATERNO has obtained dichlorinated aldehyde C,H,Cl,O by 
the action of sulphuric acid on dichloracetal. It is a liquid 
boiling at 89°—go°, attracts moisture from the air, and is thereby 
converted into a hydrate, which crystallises in beautiful laminze, 
Left to itself, even in sealed tubes, it becomes dense, and changes 
into a white amorphous mass, which has the aspect of porcelain ; 
but, when heated to 120°, is reconverted into the original product. 
Dichlorinated aldehyde dissolves without decomposition in alcohol 
and ether ; when poured into water, it first sinks to the bottom 
and then dissolves, especially on application of heat; in short, 
it exhibits the most complete analogy with chloral. It is diffi- 
cult to oxidise, its vapour not undergoing any sensible alteration 
when mixed with air or oxygen and passed over red-hot spongy 
platinum ; but when gently heated with several times its own 
volume of fuming nitric acid, it is energetically attacked and con- 
verted into dichloracetic acid C,H yCl,O0. Phosphoric penta- 
chloride attacks it strongly, producing the compound C,H ,Cl,O 
or C,H,Cl,O. C,H.Cl,, the action doubtless consisting in the 
replacement of O by Cl, (as in the action of PCI; on aldehydes 
in general), whereby C,H,Cl, is produced, which, as soon as it 
is formed, unites with a portion of the undecomposed dichlo- 
rinated aldehyde, producing the compound C,H,Cl,O. The 
constitution of this body may be represented by the following 
formulze :— CHCl,—CH,—_O—CCl,—CHCI,, 
or perhaps by CHCl,—CHCI—O—CHCI—CHC1,. 
The compound C,H,CI,O is a colourless oil, having an irritating 
odour, heavier than water, soluble in alcohol and ether ; it distils 
at 250° emitting acid vapours. Alcoholic potash attacks it 
strongly, with evolution of heat, and formation of potassium 
chloride ; and, on adding water to the resulting liquid, a heavy 
aromatic oil separates, boiling at 196°, and haying the composi- 
tion C,H,Cl,O—that is to say, containing 2HCI less than the 
preceding. This last compound unites directly with four atoms 
of bromine, forming the crystalline compound C,H,Cl,Br,O. 
In this respect, the compound C,H,Cl,O is analogous to 
Malaguti’s chlovoxethose C460, which he obtained by abstracting 
four atoms of chlorine from perchlorinated ethylic oxide C,Cl,)0. 
According to this analogy, the compound C,H,Cl,0 may be 
designated as hexchlorinated ethylic oxide, and CyH,Cl,Br,O as 
tetrachloro-tetrabrominated ethylic oxide. . The two compounds 
C,Cl,O and C,H.,Cl,O may also be regarded, respectively, as 
perchlorinated vinyl oxide and tetrachlorinated vinyl oxide.— 
{Giornale di Scienze di Palermo, v. 123, 127.] 
Colouring Matter of Wine 
Fr. PONCHIN proposes the use of a solution of potassium 
permanganate acidulated with sulphuric acid to distinguish be- 
tween the natural colouring matter of wine and the various 
substances added to imitate that colour. For this purpose a 
normal solution of 2 grammes of the permanganate in 100 
grammes of distilled water is prepared when wanted for use ; 
I5 grammes of this solution acidulated, and 3 drops of pure 
sulphuric acid, are added to 15 grammes of normal red wine 
contained in a test-tube, and the liquid after being shaken is 
left at rest. The greater part of the colouring matter is then 
slowly precipitated in red flocks, while the supernatant liquid 
retains the same colour, without weakening, for 24 hours afterwards. 
After a few days, however, the precipitate acquires a deeper red 
colour and the liquid becomes nearly colourless. For very deeply 
coloured wines a larger proportion of the normal solution must be 
used, care being, however, taken not to add it in excess, as that 
