DR. ANDREWS ON THE CONSTITUTION AND PROPERTIES OF OZONE. 
3 
on resuming the inquiry, I considered it necessary in the first instance carefully to 
repeat his experiments. The results which I at first obtained were so far in accord- 
ance with those of Baumert, -that they showed that the increase in weight of the 
apparatus was always more than the weight of the ozone, as deduced from its che- 
mical action, but the relative proportion of these quantities was not in accordance 
with his results; nor, on repeating my own experiments, did they agree with one 
another. It was evident, therefore, that some disturbing cause existed which com- 
- plicated the reaction, and, on further investigation, I not only found that such a 
cause did really exist, but succeeded in ascertaining its nature and the means of 
avoiding it. The experiments, on being now repeated, gave results very consistent 
with one another, and altogether at variance with the view that hydrogen is a con- 
stituent of ozone. 
The apparatus which I employed was arranged as follows : — A is a vessel (Plate I. 
fig. 1) of about two litres capacity, containing a mixture of one measure of pure 
and strong sulphuric acid, and seven measures of distilled water. The cylinder B, 
which is filled with a similar solution, is closed below with a diaphragm of bladder, 
so as to prevent effectually any mixture of the gases evolved at the two poles. A 
platina wire, pp, traverses and is fused into a short glass tube, fitted by grinding into 
the tubulated neck h-. this wire terminates below in a bunch of fine platina wires, 
which form the positive pole of a voltaic arrangement. The negative pole is a pla- 
tina plate, p' , immersed in the liquid of the outer vessel. The vessel A was placed 
in a larger vessel containing cold water, to which ice was in some experiments 
added. This vessel has been omitted in the drawing for the sake of distinctness. 
CC'C" is a continuous tube, united by fusion v/ith the larger neck of B, and filled 
from C to C" with fragments of pumice, moistened with pure sulphuric acid. The 
length of the desiccating column was nearly one metre. D is a Liebig’s apparatus, 
to the ends of which glass tubes were fused, which had previously been fitted by 
grinding, the one into the neck c of CC'C", the other into a tube, which was in like 
manner fused to a second Liebig’s apparatus, E. The connexions c and e were, 
therefore, formed by glass surfaces carefully ground. In my earlier experiments, 
these connexions were made by means of small and dry corks, which, on the whole, 
are more convenient than ground-glass joints, and are quite unobjectionable, as, 
when the surface is small and the cork dry, the amount of ozone destroyed by con- 
tact with the cork is wholly inappreciable. Caoutchouc connectors of any kind are 
altogether inadmissible; they are attacked with such energy by ozone, even when 
diluted with 1000 times its volume of other gases, tl)at the tube becomes perforated 
in the course of a few minutes. The vessel D contained a solution of iodide of 
potassium, acidulated with a little hydrochloric acid, and the vessel E, concentrated 
sulphuric acid. The U-tube F, filled with pumice moistened with sulphuric acid, 
prevented any moisture from passing backwards into E. The oxygen evolved was 
collected in the graduated glass vessel G, inverted over water. The volume of the 
B 2 
