238 Dr. Faraday on Magnetic and Diamagnetic Action. 
metals and a metal taken from near the neutral point. Still there 
is this difference remaining between the conditions of the experi- 
ment and the hypothetical case; that in the former the induction: 
is manifested by currents in the masses, whilst in the latter, 7. ¢ 
in the special magnetic and diamagnetic effects, the currents, if 
they exist, are probably about the particles of the matter. 
2432. The magnetic relation of ariform. bodies is exceodinght 
remarkable. ‘That oxygen or nitrogen gas should stand in a 
position intermediate between the magnetic and diamagnetic 
classes; that it should occupy the place which no solid or liquid 
element can take ; that it should show no change in its relations 
by rarefaction to any possible degree, or even when the space it 
occupies passes into a vacuum; that it should be the same mag- 
netically with any other gas or vapor,; that it should not take 
its place at one end but in the very middle of the great series of 
bodies ; and that all gases or vapors should be alike, from the rar- 
est tate of hydrogen to the densest state of carbonic. acid, sul- 
phurous acid, or ether vapor, are points so striking as to persuade 
one at once that air must have a great and perhaps an active part 
to play in the physical and_ terrestrial arrangement of ago 
forces. 
2433. At one time I looked. to air and gases as the bodies 
which, allowing attenuation of their substance without addition, 
would permit, of the observation of corresponding variations M 
their magnetic properties; but now all such power by rarefaction — 
appears to be taken away; and though it is easy to prepare 4 
liquid medium which shall act with other-bodies as air does 
(2422), still it is not truly in the same relation to them ; neither 
does it allow of dilution, for to add water or any such substance ~ 
is to add to the diamagnetic power of the liquid ; and, if it were 
possible to convert it into vapor and so dilute it by heat, it 
would pass into the class of gases and be magnetically undistiD- 
guishable from the rest. 
2434, It is also very remarkable to observe the apparent dis- 
appearance of magnetic condition and effect when bodies assume 
the vaporous or gaseous state, comparing it at the same time with 
the similar relation to light ; for as yet no gas or vapor has beet — 
_ MInade to show any magnetic influence over the polarized ray; 
even by the use of powers far more than enough to manifest 
er men ah it bene, 
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