NOTES AND ABSTRACTS IN CHEMISTRY AND PHARMACY. 23 
AVith reference to these experiments on the production of acetylene by imper¬ 
fect combustion, Berthelot states:—“The quantity of acetylene which manifests 
itself under these circumstances in the form of acetylide is evidently greater 
than that which is produced under the influence of heat alone, acting upon the 
same compounds. The quantity of acetylene really produced is besides much 
superior to that which becomes manifest in the form of acetylide, because the 
greater part of the acetylene burns almost immediately after being formed, and 
without coming in contact with the reagent. It is therefore probable that, by 
suitably modifying the experiment, a more advantageous method may be found 
for preparing acetylene than is at present known.” Mr. M‘Leod has described^ 
an apparatus constructed in accordance with this suggestion. He inverts the 
method of burning, and employs an adaptation of the ordinary apparatus for 
burning oxygen in an atmosphere of hydrogen. It consists of a glass cylinder, 
with an opening at the top through which a constant stream of marsh gas is 
passed in, and two openings at the bottom, through one of which passes in a 
tube and jet at which oxygen is burnt, and from the other passes a tube leading 
to a wash-bottle containing the cuprous solution. By this means, Mr. M‘Leod 
states, it is easy to obtain from marsh gas a gramme and a half of cuprous ace¬ 
tylide in an hour. The oxygen may be easily replaced by atmospheric air, and, 
in place of marsh gas, coal gas may be used, perhaps charged with ether vapour, 
and the process thus rendered very practicable. 
M. de Wilde has shownf that acetylene is also formed in the well-known ex¬ 
periment of burning a mixture of olefiant gas and chlorine. 
M. Reboul has studied the action of bromine on acetylene. Besides the liquid 
bibromide,!; C 2 H 2 Br 2 , already known, he describes a brominated compound, 
CoHBr, which is gaseous. He has also obtained a tetrabromide, C 2 H 2 Br 4 . De 
AAdlde has also submitted acetylene and hydrogen to the action of platinum 
black, and has thereby obtained a gaseous body which he is inclined to regard 
as hydride of ethyle— 
aiio + H^ = C2H5 ,h. 
Acetylene. Hydride of ethyl. 
The action of potassium and sodium on acetylene, and the nature of the com¬ 
pounds which acetylene forms with copper, silver, chromium, and gold, have 
recently formed the subject of a memoir by Berthelot. He regards the latter 
compound as a new class of compound metallic radicals. 
Pwrity of S’lagnesitim. 
hlessrs. AVanklyn and Chapman || have examined samples of commercial mag¬ 
nesium, such as is sold for exhibiting the magnesium light, and their results 
show it to be remarkably pure. 
Their method of examination is to determine the volume of hydrogen evolved 
by the solution of a given weight of metal in dilute acid, either acetic, hydro¬ 
chloric, or sulphuric. Considering the low equivalent of magnesium, and the 
accuracy with which hydrogen may be measured when collected over water 
saturated with air, they regard this method of estimation as an extremely ri¬ 
gorous one. 
Tlie apparatus employed is very simple. A small vessel, such as is used for 
determinations of carbonic acid, is used, and the gas passes by a bent tube to a 
graduated jar standing over water. When a known weight of metal has en¬ 
tirely dissolved, it is only necessary to read off the volume of gas, and make the 
usual reductions for temperature, pressure, and aqueous vapour. 
Jour, of Chem. Soc. May 18GG, p. 161. 
XC = 12. 
t Bull, de Soc. Chim. Atarcli 1866. 
11 Jour, of Chem. Soc. May 1866, p. 141. 
