Scientific Intelligence — Meteorology. 179 



disengage the electric odour at a Io\v temperature, ddso iio longer 

 when heated to their boiling point. 



3c?. The odoriferous substance which is disengaged from the 

 positive wire, may be inclosed and preserved in a well- corked ves- 

 sel. 



4th. When into a vessel containing this substance, there is thrown 

 a small quantity of powdered charcoal, or filings of iron, zinc, tin, 

 lead, bismuth, arsenic, antimony, or a few drops of mercury or ni- 

 trous acid, or of a solution of protosulphate of iron, or of proto- 

 chloride of tin or iron, the odour is nearly in a moment entirely de- 

 stroyed ; and at a high temperature, gold and platina produce the 

 same effects. When a plate of gold or platina, whose surface is 

 quite dry and free from tarnish and cold, is plunged into a jar con- 

 taining this substance, the metal becomes negatively electrified, or, 

 in other words, a plate of platina heated in this way, forms with 

 another plate of the same metal in its natural condition, a voltaic 

 element. The metals which are readily oxydized, are not nega- 

 tively polarized in the same circumstances. The author, in the 

 course of the previous year, had demonstrated that the precious 

 metals assumed negative polarity when they are plunged for a little 

 time into an atmosphere, of chlorine or bromine. This negative 

 polarity of platinum is destroyed when the plate is plunged for a 

 i\i\Y instants into an atmosphere of hydrogen. 



M. Schoenbein regfirds the odorous principle which he has been 

 examining, as a distinct body which ought to be classed with the kind 

 of bodies to which chlorine and bromine belong, among elementary 

 and halogenous substances. He proposes to give it the name of 

 Ozone. He considers it certain, that this body is always disengaged 

 in the air, and in very considerable quantities during the time oC 

 thunder storms. 



2. Polar Lights. — Some of the labours of the French Scientific 

 Expedition to high northern latitudes, have been lately submit- 

 ted to the attention of the Royal Academy of Sciences, and from 

 these interesting documents we now select a i'GW particulars on 

 Polar lights. Between the 12th of September 1838, and the 18th 

 of April 1839, 153 appearances of the aurora borealis were ob- 

 served ; sometimes the phenomenon was noticed as early as half- 

 past three in the afternoon, and sometimes it continued till five in 

 the morning. It has often afforded light to read a printed book, 

 and frequently, of nearly the smallest type. Parallactic observa- 

 tions, which have been taken at Dupvig and Bossekop, the two ex- 

 tremities of a base eight and a half miles long, between the 9th 

 and 22d of January 1839, seem to assign to those auroras which 



