Chamberss Edinburgh Journal, No. 455 | Page 7

substances. Now, a continuous cause, and acting on so vast a

scale, would necessarily diffuse through the atmosphere a considerable
mass of miasmatic gases, and accumulate them till at length it would be
completely poisoned, and rendered incapable of supporting animal life,
if nature had not found the means of destroying these noxious matters
in proportion as they are produced.'
The question then arises: What are the means employed for this object?
M. Schoenbein believes that he has found it in the action of ozone,
which is continually formed by the electricity of the atmosphere, and is
known to be a most powerful agent of oxidation, causing serious
modifications of organic bodies, and, consequently, of their
physiological action. 'To assure myself,' he pursues, 'that ozone
destroys the miasma arising from the decomposition of animal matters,
I introduced into a balloon containing about 130 pints of air, a piece of
flesh weighing four ounces, taken from a human corpse, and in a very
advanced state of putrefaction. I withdrew it after a minute; the air in
the balloon had acquired a strong and very repulsive odour, shewing
that it was charged with an appreciable quantity--at least for the
smell--of miasm caused by the putrefaction.
'To produce ozone, I introduced into the infected balloon a stick of
phosphorus an inch long, with water sufficient to half cover it. At the
same time, for the sake of comparison, I placed a similar quantity of
phosphorus and water in another balloon full of pure atmospheric air.
After some minutes, the reaction of ozone in the latter was most
evidently manifested, while no trace of it was yet apparent in the
former, which still gave off an odour of putrefaction. This, however,
disappeared completely at the end of ten or twelve minutes, and
immediately the reaction of the ozone was detected.'
The conclusion drawn from this experiment is, that the ozone destroyed
the miasm by oxidation, and could only make its presence evident after
the complete destruction of the noxious volatile substances. This effect
is more strikingly shewn by another experiment.
A balloon of similar capacity to the one above mentioned was charged
as strongly as possible with ozone, and afterwards washed with water.
The same piece of flesh was suspended within it; and the opening being

carefully closed, it was left inside for nine hours before the air of the
balloon presented the least odour of putrefaction. The air was tested
every thirty minutes by an ozonometer, and the proportion of ozone
found to be gradually diminishing; but as long as the paper of the
instrument exhibited the slightest trace of blue, there was no smell,
which only came on as the last signs of ozone disappeared. Thus, all
the miasm given off by the piece of flesh during nine hours was
completely neutralised by the ozone with which the balloon had been
impregnated, so small in quantity as to be but the 6000th part of a
gramme. One balloon filled with ozonified air, would suffice to
disinfect 540 balloons filled with miasmatic air. 'These considerations,'
says M. Schoenbein, 'shew us how little the miasma of the air are to be
appreciated by weight, even when they exist therein in a quantity very
sensible to the smell, and how small is the proportion of ozone
necessary to destroy the miasm produced by the putrefaction of organic
substances, and diffused through the atmosphere.'
The presence of ozone in any vessel or in the atmosphere, may be
detected by a test-paper which has been moistened with a solution
composed of 1 part of pure iodide of potassium, 10 parts of starch, and
100 parts of water, boiled together for a few moments. Paper so
prepared turns immediately blue when exposed to the action of ozone,
the tint being lighter or darker according to the quantity. Schoenbein's
ozonometer consists of 750 slips of dry bibulous paper prepared in the
manner described; and with a scale of tints and instructions, sufficient
to make observations on the ozone of the atmosphere twice a day for a
year. After exposure to the ozone, they require to be moistened to bring
out the colour.
M. Schoenbein continues: 'We must admit that the electric discharges
which take place incessantly in different parts of the atmosphere, and
causing therein a formation of ozone, purify the air by this means of
organic, or, more generally, oxidizable miasma; and that they have thus
the important office of maintaining it in a state of purity suitable to
animal life. By means of atmospheric electricity, and, indirectly, nature
thus attains on a great scale the object that we sometimes seek to
accomplish in a limited space by fumigations with chlorine.

'Here, as in many other cases, we see nature effecting two different
objects at one stroke. For if the oxidizable