560 PLUCKER ON THE ACTION OF THE MAGNET 



seen even without covering it with the case of the torsion-balance, 

 which the apparatus for evolving steam did not permit. 



When the aqueous vapour was made to ascend in the same 

 way between the two jjarallelopipedal halves of the keeper (A), 

 approximated to 3*5 millims., at the moment of the closure of 

 the circuit, it was forced from the intermediate space between 

 them and extended laterally in the equatorial plane. 



Aqueous vapour is thus even more strongly diamagnetic than 

 air. 



13 a. The following proceeding was adopted for examining 

 the magnetic relation of the vapour of mercury. The conducting 

 wire issuing from the platinum end of a battery of twelve cells 

 was cond\icted into a vessel containing mercury, w-hich stood 

 immediately under the apices of the poles, whilst the conducting 

 wire emanating from the zinc end was coiled round the iron 

 nucleus of the magnet, and afterwards terminated in the mercury. 

 The circuit was opened by withdrawing the former conducting 

 •wire from the mercury, and again closed w hen the vapour of the 

 mercury accompanying the sparks arising from the separation 

 ascended between the apices of the pole=. The anticipated re- 

 pulsion then occurred. Hence the vapour of mercury is also more 

 strongly diamagnetic than air. 



14. Since the different kinds of flames are nothing more than 

 gases produced by the process of combustion, at a red heat, with 

 or without an admixture of solid matters at a red heat, it became 

 of interest to subject them also to the action of the magnet. On 

 so doing very beautiful phaenomena resulted ; these exhibited 

 great variety, according as on the one hand the form of the poles 

 and their distance apart were altered, and on the other various 

 kinds of flames Avere used. When the keeper (B), with the 

 conical apices screwed on, was applied, most remarkable phse- 

 nomena presented themselves. These I shall particularly de- 

 scribe*. 



15. When a common stearine candle was placed midway be- 



* M. Zantedesdii, a short time since, made a communication to the Academy 

 of Sciences at Paris, to the effect that various flames are repelled and depressed 

 when in proximity to the poles of a magnet. I at once thought to recognize 

 in this pht^nomenon a diamagnetic action ; and this circumstance, in combina- 

 tion with the theoretical considerations developed in paragraph 4, gave I'ise to 

 the first part of the present treatise. In my experiments, the two assistants 

 of the physical cabinet, M. vom Koike and M. Beer, aided me materially; 

 the drawings from nature were principally made by the latter. 



