66 Scien tific Intelligence. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHYSICS. 
1. On the existence of Ozone in the Atmosphere.—In an elab- 
orate paper upon the reactions hitherto relied on to prove the 
presence of ozone in the atmosphere, Scnéne has discussed the 
value of the chemical evidence, and concludes that we have at 
present no test by which the existence of ozone, in the small quan- 
tity likely to be present in the air, can be established. Since the 
author has previously shown that hydrogen peroxide is a normal 
constituent of atmospheric air, the question now raised is whether 
ozone is also present. The tests used therefore must discriminate 
between these two substances. Schdnbein proposed three 0 
these tests; the production of free iodine and potassium hydrate 
from potassium iodide; the oxidation of thallous to thallic oxide ; 
and the oxidation of manganous to manganic oxide. The author 
has proved that the first two reactions take place readily with 
hydrogen peroxide; and that the latter requires a trace of am- 
monium carbonate; the paper then turning brown not only by 
the peroxide but even by oxygen alone. Houzeau’s test, red lit- 
mus paper, dipped in potassium iodide solution, also reacts with 
H,O, as with ozone. The proofs offered by Andrews, that air 
which acted on potassium iodide, lost this property on heating to 
260° or by contact with manganese dioxide, are as well, if not 
better explained by the existence of H,O, in the air. The onl 
author by no means denies the existence of ozone in the atmos 
phere, even coéxistent with hydrogen peroxide, the two reacting 
n each other very slowly. But he maintains that there is no 
experimental evidence of its presence— Ber. Berl. Chem. Ges. 
xiil, 1503, Sept., 1880. G. F. B 
2. On the Meteorological use of Thallium-papers.—ScHoEN® 
has given in a subsequent paper, the results of an extended series 
f experiments on the use of thallium-paper for estimating 4P- 
proximately the oxidizing material in the atmosphere, whether 
