ATMOSPHERIC ELECTRICITY AND OZONE. 459 



were usually accompanied by an increase of positive electricity ; this 

 observation is of interest, because it accords with the fact that the ap- 

 proach of snow-storms and the presence of simple fog do not cause 

 the exacerbations of rheumatic and neuralgic pains that are experi- 

 enced on the approach of storms of rain, or thunder and lightning. 



Ozone- History. — From the earliest recorded ages a peculiar odor 

 has been observed during thunder-storms and other electrical disturb- 

 ances, and especially in connection with flashes of lightning. The 

 peculiar odor of thunder-bolts has been referred to by Homer, both in 

 the " Iliad " and the " Odyssey." Jupiter is said to strike a ship with a 

 thunder-bolt, "&v de deecov ttXtjto" full of sulphurous odor, and to 

 hurl a bolt into the ground "with the flame of burning sulphur." 

 This peculiar sulphurous odor has been observed not only during 

 thunder-storms, but also, it is said, during displays of northern and 

 southern aurorae. 



So long ago as 1785, Van Marum, of Holland, observed that electric 

 sparks passed through oxygen gas (that had been discovered by 

 Priestley only eleven years before) gave rise to a peculiar sulphurous 

 or electrical odor ; and, at the beginning of the present century, Ca- 

 vallo, a prominent name in the history of electricity, called attention 

 to the fact that this " electrified air," as it was termed, had an anti- 

 septic effect on decomposing matter, and was a salutary application 

 for fetid ulcers. In 1826 Dr. John Davy, in a measure anticipating 

 Schonbein, recognized this peculiarity of the atmosphere, and devised 

 tests for detecting it. 



The real scientific history of ozone dates from 1839, when Prof. 

 Schonbein, of Basle, the renowned inventor of gun-cotton, observed 

 that the electrolytic decomposition of water was attended by a pecul- 

 iar odor resembling that evolved during the working of a frictional 

 electric machine. In 1840 Schonbein called the attention of the scien- 

 tific world to the newly-discovered substance, to which he gave the 

 name of ozone, from the Greek ofiw, to emit an odor. He showed that 

 this odor appeared at the positive pole during the electrolysis of 

 water. He furthermore pointed out that ozone may be produced by 

 the slow oxidation of phosphorus in moist air or oxygen, and that the 

 odor was similar to that which is observed during flashes of light- 

 ning. Schonbein studied hard on the subject for many years, and ar- 

 rived at the conclusion that oxygen is capable of division into a nega- 

 tively polar state, ozone, and a positively polar state, which he called 

 antozone. During the past quarter of a century the subject of ozone 

 has been studied by some of the most eminent scientists of the age, 

 among whom we may mention the names of Berzelius, De la Rive, 

 Marignac, Becquerel, Faraday, Fremy, Meissner, Houzeau, Scout- 

 teten, Odling, Andrews, Tait, Fox, Fischer, Boeckel, Zeuger, Moffat, 

 Nasse, Engler, Erdmann, Angus Smith, Poey, A. Mitchell, Soret, Bau- 

 mert, Williamson, and verv manv others. 



