blem of artificial lighting will have been solved.

* * * * *

ON PURIFICATION OF AIR BY OZONE--WITH AN ACCOUNT OF A NEW METHOD.[1]

[Footnote 1: Paper read in Section C, Domestic Health, at the
Hastings Health Congress, on Friday, May 3, 1889.]

By Dr. B. W. RICHARDSON.

During the time when I was engaged in my preliminary medical
studies--for I never admit to this day of being anything less than a
medical student--the substance called ozone became the topic of much
conversation and speculation. I cannot say that ozone was a discovery
of that date, for in the early part of the century Von Marum had
observed that when electrical discharges were made through oxygen in a
glass cylinder inverted over water, the water rose in the cylinder as
if something had either been taken away from the gas, or as if the gas
itself had been condensed, and was therefore occupying a smaller
space. It had also been observed by many electricians that during a
passage of the electric spark through air or oxygen, there was a
peculiar emanation or odor which some compared to fresh sea air,
others to the air after a thunderstorm, when the sky has become very
clear, the firmament blue, and the stars, if visible, extremely
bright.

But it was not until the time, or about the time, of which I have
spoken, 1846-49, that these discovered but unexplained phenomena
received proper recognition. The distinguished physicist Schonbein
first, if I may so say, isolated the substance which yielded the
phenomena, and gave to it the name, by which it has since generally
been known, of _ozone_, which means, to emit an odor; a name, I have
always thought, not particularly happy, but which has become,
practically, so fully recognized and understood, that it would be
wrong now to disturb it.

Schonbein made ozone by the action of the electric spark on oxygen. He
collected it, he tested its chemical properties, he announced it to be
oxygen in a modified form, and he traced its action as an active
oxidizer of various substances, and especially of organic substances,
even when they were in a state of decomposition.

But Schonbein went further than this. He argued that ozone was a
natural part of the atmosphere, and that in places where there was no
decomposition, that is to say, in places away from great towns, ozone
was present. On the high tower of a cathedral in a big city he
discovered ozone; in the city, at