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Transactions of the 



while upon the summit of the Senlis, near Appenzell, was 

 suddenly involved in a thunderstorm. His servant was 

 struck dead, and his tent was filled with the peculiar odour 

 common to such occurrences. Chancing shortly afterwards 

 to pay a visit to Schonbein at his laboratory, where he was 

 engaged in the prosecution of some researches upon ozone, 

 the smell of which pervaded the apartment, the engineer 

 exclaimed with surprise that it wt the identical odour he 

 had perceived upon the summit of the Senlis. This identity 

 has been fully proved, as I shall further on have occasion to 

 notice. 



The connection between the presence of ozone and the 

 existence of certain epidemics, has given rise to some curious 

 speculations. ' Ozone,' says Mr. Hunt (' Athenseum ') ' is con- 

 stantly produced in the atmosphere under every circumstance 

 which determines either electrical or chemical changes.' 

 Both animals and vegetables are constantly throwing off 

 minute particles of organic matter, whether in a state of 

 health, disease, or death, and these particles are in that con- 

 dition most fitted for recombination with the chemical ele- 

 ments of the air. These exhalations would speedily become 

 far more injurious to all forms of animal life upon the globe 

 than the carbonic acid to which they are reduced by oxidation, 

 the work of the ozone, were it not for their removal. Ozone 

 is thus, so to speak, the great natural scavenger employed to 

 remove any noxious organic particles from the air, and con- 

 vert them into innocuous forms of matter. Since the dis- 

 covery of ozone and development of ozonometry, the year 

 1849 stands out conspicuous for the remarkable low electrical 

 intensity of the atmosphere during the summer and autumn 

 months, and since this is the only source of ozone in any 

 practical consideration, it follows that this important chemical 

 agent must also have been materially diminished in quantity.' 



The following is a table of the mean electrical intensity of 

 that year, accompanied by the mean of the five preceding 

 years according to M. Quetelet : — 



' ' Ozone varies in amount in an exact ratio with the electrical intensity.' — R. 

 Hunt, Atheyiaum. 



