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determine with greater certainty and exactness than has 
yet been done, the nature of the changes to which this 
important constituent of the earth’s atmosphere is subject, 
and of their relation to other atmospherical phenomena. 
Professor H. E. Roscoe, F.R.S., exhibited and explained 
the method of producing ozone artificially, and showed how 
it had been proved by Dr. Andrews and M. Soret that 
ozone was an alio tropic condition of oxygen, and that three 
volumes of oxygen formed two volumes of ozone. 
