286 
NATURE 
[uly 23, 1885 
given me interesting results, which, however, it will be difficult 
to describe in this short ‘preliminary note. I will only say that 
all the bands specified above (except sometimes 104;%;) are 
especially very marked in the earth which is most easily precipi- 
tated by ammonia, which has a sulphate least soluble in potassic 
sulphate, and whose chloride, very soluble in pure water, is 
difficultly soluble in concentrated hydrochloric acid. 
“*Shall we find two earths respectively characterised by the 
bands 104;% and a 1154? 
““The production of my reversion spectrum appears to be 
analogous physically with the formation of the phosphorescence 
spectra obtained by Mr. Crookes at the positive pole in his high 
vacuum tubes containing certain compounds of yttria. The con- 
ditions of the two experiments are, however, very different practi- 
cally speaking. 
“*Tt is a singular fact that the positions of the phosphorescence 
bands observed by Mr. Crookes with very pure compounds of 
yttrium, are sufficiently near those which I, on my part, have 
obtained with hydrochloric solutions of the earths separated as 
widely as possible from yttria, chemically as well as spectro- 
scopically. My reversion spectrum cannot, I think, be attributed 
to yttrium, for on the one hand it is seen /yz/Ziantly with products 
which give no trace of yttrium rays by the direct spark, and on 
the other hand I have found it impossible to obtain it sharply 
from certain earths extremely rich in yttria. 
“As soon as my work is sufficiently advanced to enable me 
to arrive at some definite conclusion, I shall have the honour of 
informing the Academy of it.” 
M. Lecoq de Boisbaudran added the following additional 
note :-— 
I have not yet finished the very long work undertaken in the 
hope of determining the nature of the above described phosphor- 
escence spectrum. 
This spectrum is now recognised as being identical with that 
which is ascribed to pure yttria by Mr. Crookes, and which this 
savant obtained under experimental conditions very different to 
mine. Nevertheless my latest observations, as well as the older 
ones, lead to the conclusion that yttria is not the cause of the 
spectrum bands observed. In my fractionations the phosphor- 
escence spectrum regularly gets weaker as I advance towards the 
yttria end. With almost pure yttria the phosphorescence bands 
show themselves faintly or not at all, whilst they are brilliant 
with the earths which do not give by the direct spark the rays 
of yttrium to an appreciable extent. 
The prodigious sensibility of Mr. Crookes’s reaction, which 
detects a millionth part of his purified yttria, makes very singular 
this divergence which I am obliged to point out between the 
conclusions of the eminent English chemist and myself. Mr. 
Crookes has willingly undertaken to examine some of my pro- 
ducts in his high-vacuum tubes; and, on the other hand, he has 
promised to send me the earths prepared by himself, so that I 
can examine them by my process. A comparison of these cross 
experiments, it is hoped, will throw some light on the question 
of the origin of the phosphorescence spectrum. 
Another conclusion from my researches, a conclusion which I 
publish with a certain reserve because my work is not yet 
finished, is that the bands 105 and 115 do not belong to the 
same element. On this hypothesis, based on the fact that some 
of my products give 105 notably stronger than 115, whilst others 
show 115 brightly and 105 faintly, I will provisionally call Za 
the earth characterised by 105, and Z@ the earth giving 115. 
Space does not allow me to describe to-day the principal ex- 
periments or observations undertaken to find out what are Za 
and Z ; this will form the subject of another memoir. 
I should acknowledge here that Mr. Crookes was the first to 
see the phosphorescence spectrum of samarium. During the 
past year only this spectrum was pointed out to me by my learned 
friend M. Demargay, to whom I had confided the secret of my 
method for the production of phosphorescence spectra by the 
reversion of the induced current. I then made a drawing of it.— 
Comptes Rendus, vol. c. p. 1437, June 8, 1885. 
SOCIETIES AND ACADEMIES 
LONDON 
Chemical Society, June 18.—Dr. Hugo Miiller, F.R.S., 
President, in the chair.—Messrs. Jos. F. Burnett and Harry M. 
Freear were formally admitted Fellows of the Society.—The 
following gentlemen were duly elected Fellows of the Society :— 
Messrs. Harry Haslett, Thomas Cradock Hepworth, Leonard 
de Koningh, Charles Langer, Arthur Richardson, James Sharp, 
James Pender Smith, James Spilsbury.—The following papers 
were read :—On the decomposition and genesis of hydrocarbons 
at high temperatures: I., the products of the manufacture of 
gas from petroleum, by Henry E. Armstrong and A. K. Miller, 
Ph.D. Having carried the examination of the various products 
of the decomposition of petroleum effected at high temperatures, 
in the manufacture of oil-gas (see paper in the ¥ournal of the 
Society of Chemical Industry, September, 1884), as far as can 
usefully be done with the material originally dealt with, the 
authors now describe their methods and results ; they remark, 
however, that these must be regarded as little more than pre- 
liminary, and that it will be necessary to repeat the investiga- 
tion on a much larger scale, and to introduce new and improved 
methods. The products examined are (1) the portion of the 
compressed gas which combines with bromine; (2) the liquid 
deposited during compression of the gas to about ten atmo- 
spheres ; {3) the portion of the tar which is volatile in steam. 
(1) By far the chief constituents of the mixture of bromides ob- 
tained by scrubbing the compressed gas by bromine are ethylene 
bromide and crotonylene tetrabromide, C,H Br, ; propylene and 
butylene bromides have also been separated from it. ‘The gas is 
practically free from hydrocarbons of the acetylene series capable 
of producing a precipitate in an ammoniacal cuprous solution. 
(2) The liquid deposited during compression of the gas is a com- 
plex mixture of olefines, of hydrocarbons of the C,,H4,,_» series, 
and of benzenes. The presence in it of xormal amylene, 
hexylene, and heptylene has been demonstrated by the study of 
the products of oxidation of the various fractions. It is saturated 
with crotonylene, and contains a considerable quantity of the 
next homologue, C;H,; this latter hydrocarbon has not been 
previously described ; it boils at 45°, and yields a tetrabromide 
which crystallises from alcohol in long flat prisms melting at 
114°. All attempts to separate a hydrocarbon having the 
properties of Schorlemmer’s hexoylene from the fraction boiling 
at 80°-82° have hitherto been unsuccessful, the statement 
previously made by one of the authors that this hydrocarbon was 
present having been based on determinations which haye since 
been discovered to be faulty. The liquid deposited during com- 
pression of oil-gas is rich in benzene and toluene, but contains 
only traces of higher benzenes. (3) The steam distillate from 
the tar contains the less volatile hydrocarbons present in 
the liquid deposited during compression of the gas, together 
with a great variety of others. It is rich in hydrocarbons which 
are readily polymerised by sulphuric acid ; these appear to be 
mainly members of the C,H,,_. series, such as Schorlemmer 
discovered in the light oils from cannel and boghead coal, and 
which yield no acid higher than acetic on oxidation. The three 
xylenes and mesitylene and pseudocumene are present in about 
the same relative proportions as in ordinary coal-tar ; but in addi- 
tion, the oil-gas tar contains certainly one—probably two—higher 
members of the benzene series: the amount obtained has not 
been sufficient, however, to permit of the precise determination 
of its nature. A very considerable amount of naphthalene may 
be separated from the tar ; benzenoid hydrocarbons of higher 
boiling point than napthalene have also been obtained in small 
quantity. A certain, although relatively small, amount of a 
complex mixture of saturated hydrocarbons has also been 
separated from the tar: the quantity of material at their dis- 
posal has not enabled the authors to separate these to their 
satisfaction, and in a state sufficiently approaching purity ; they 
are inclined to believe, however, that the mixture does not 
consist of paraffins, but of hydrocarbons of the C,H, series 
—such as form the chief constituents of Russian petroleum. 
The hydrocarbons mentioned are by no means the sole constitu- 
ents of the material examined, but merely those which have been 
proved to be present. The theoretical conclusions to be deduced 
from the results are in some respects interesting. It would 
appear that only xormal olefines are present, and it is also re- 
markable that apparently this series is not represented by terms 
higher than heptylene. No true acetylenes have been detected ; 
the crotonylene obtained is either methylallene, CH,°CHC*CHg, 
or dimethylene-ethane, CzH.(CH,)., and from their behaviour on 
oxidation it is probable that the homologous hydrocarbons are 
closely related to it. Hence it may be inferred that in the 
formation of hydrocarbons of the C,H)». series at high tem- 
peratures from normal olefines of the formula C, H.,+,"CH CH, 
two atoms of hydrogen are removed in such a way that the 
terminal CH 3°CH, radicle in the formula becomes either 
