412 Dr. Faraday 07i the Diamagnetic conditions 



with the character of its elements. It could also be very well 

 indicated by reddened litmus paper held over the tubes. 



Chlorine was sent from the WoulPs bottle apparatus, and 

 proved to be decidedly diamagnetic in air. Either ammonia by 

 its fumes, or litmus paper by its becoming bleached, served 

 to indicate the entrance of the chlorine into the side catch- 

 tube every time the magnet was rendered active. 



Iodine. — A piece of glass tube was so shaped at its lower 

 extremity as to form a chamber for the reception of iodine, 

 which chamber had a prolonged mouth directed downwards 

 so as to deliver the vapour formed within. On putting a little 

 iodine into the chamber, then heating it, and especially the 

 mouth part, by a spirit-lamp, and afterwards inclining the 

 apparatus, abundance of the vapour of iodine was generated 

 as the substance flowed on to the hotter parts, and passed in 

 a good stream from the mouth downwards. This purple 

 stream was diamagnetic in air, and could be seen flowing right 

 and left from the axial line, when not too dense. If very dense 

 and heavy, its gravity was such as to make it break through 

 the axial line, notwithstanding the action of the magnet; still 

 it was manifest that iodine is diamagnetic to air. 



Bromine. — A little bromine was put into the horizontal part 

 of the delivery tube, and then air passed over it by the apparatus 

 already described. So much bromine rose into vapour as to 

 make the air of a yellow colour, and caused it to fall well in 

 a stream by the axial line. A little ammonia delivered near 

 the magnetic field showed that this stream was diamagnetic, 

 and hence it may fairly be presumed that the pure vapour of 

 bromine would be diamagnetic also. 



Cyanogen. — Strongly diamagnetic in air. 



Taking air as the standard of comparison, it is very striking 

 to observe, that much as gases appear to differ one from an- 

 other in the degree of their diamagnetic condition, there are 

 very few that are not more diamagnetic than it; and when the 

 investigation is carried forward into the relation of the two 

 chief constituents of air, oxygen and nitrogen, it is still more 

 striking to observe the very low condition of oxygen, which, 

 in fact, is the cause of the comparatively low condition of air. 

 Of all the vapours and gases yet tried, oxygen seems to be 

 that which has the least diamagnetic force. It is as yet a 

 question where it stands ; for it may be as low as a vacuum, 

 or may even pass to the magnetic side of it, and experiment 

 does not as yet give an answer to the question. I believe it to 

 be diamagnetic ; and this belief is strengthened by the action of 

 heat upon it, to be described hereafter; but it is exceedingly low 

 in the scale, and far below chlorine, iodine, and such like bodies. 



