428 
POPULAR SCIENCE REVIEW. 
electricity on mixtures of certain gases has been lately shown by Sir Benj a- 
niin Brodie (P. R. S. April 3, 1873), to yield very interesting results. An 
obvious application of his method was to treat a mixture of dry hydrogen 
and nitrogen in a similar manner as those referred to above, with the view 
of effecting the synthesis of ammonia ; and Sir B. Brodie kindly allowed 
me the use of his apparatus for the purpose of the experiment, which was 
conducted as follows : — A mixture of about three volumes of hydrogen with 
one of nitrogen in a bell-jar over water, was passed through two tubes 
containing pumice moistened with alkaline pyrogallate and sulphuric acid 
respectively, then through a Siemen’s induction-tube, and into a bulb con- 
taining dilute hydrochloric acid. The whole apparatus being first filled 
with pure hydrogen, about half a litre of the mixed gases was sent through 
the apparatus, the induction coil not being in action ; the bulb containing 
the acid was then removed and another substituted, containing an equal 
volume of the same acid. About half a litre of the mixed gases was now 
passed through the apparatus, submitting them to the action of the elec- 
tricity. The contents of the two bulbs were next transferred to two test- 
tubes; and after adding excess of potash to each, NesslePs test was applied. 
The first solution gave a faint yellow coloration, the second a rather thick 
reddish-brown precipitate. No attempt was made to estimate the quantity 
of ammonia formed, as it would vary with many of the conditions of the 
experiment.” 
Activity of Chlorine in Dai'kness . — This is an interesting subject, especially 
as chlorine is supposed to act almost exclusively in the light. However, 
M. Melsens has observed that carbon in the form of coke, purified by 
repeated washings and ignitions in a current of dry chlorine, can absorb 
nearly its own weight of this gas. If now a current of hydrogen, previously 
dried over phosphoric oxide, be passed over this chlorinated carbon, even 
cold and in absolute darkness, notable quantities of hydrochloric acid gas 
are disengaged. A true combustion of hydrogen in chlorine takes place, 
the temperature being actually lowered by the return of the chlorine to the 
gaseous state. — Vide “ Comptes Rendus,” Ixxvi. p. 92. 
Amount of Ozone absorbed by Water. — M. L. Carius has previously shown 
that ozone can be absorbed by water unchanged, in quantities not incon- 
siderable. He now finds that at a temperature of 0°, and a pressure of 
0*76 m.m., 1-346 c.c. of ozone were absorbed by 100 c.c. of water; this is 
independent of the amount of oxygen absorbed. The ozone used in these 
experiments was obtained by electric action. — ^‘Berichte der Deutschen 
Chemischen Gesellschaft zu Berlin,” July 14. 
Improvement in Photo-lithography. — In one of the numbers of the Chemical 
News” for August, M. Paul gives the following description of his pro- 
cess : The paper is coated with a layer of white of egg beaten up, and 
mixed with a concentrated solution of bichromate. When dry it leaves 
a hard smooth surface. After a sufficient insolation under the negative, 
the paper is covered with lithographic ink, then immersed in cold water 
to dissolve out the unchanged albumen, which is then removed with a fine 
sponge.” 
A new Deodoriser for Prevention of Epidemics. — In Les Mondes ” 
(August 14) M. Chodzko declares that the phenols, the hypochlorites, and 
