20 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXV.) 
2768. There is no difficulty in applying this method of observation to experiments 
with gases in atmospheres of other gases than air, provided they be such as do not 
destroy the bubble ; but I do not consume time by detailing the results of such ex- 
periments, which accorded perfectly with those before obtained The description 
given is quite sufficient to illustrate the point stated, namely, that the motions of the 
gases, one in another, when in the magnetic field, is a differential result, and supply 
sufficient cases for reference hereafter. 
2/69. The same conclusion, that the effect is a differential result of the masses of 
matter present in the magnetic field, is also manifest from the consideration of the 
cases of gaseous, liquid, and solid diamagnetic bodies, advanced in a former part of 
these Researches( 2405-14.) ; and a conclusion of the same kind, as regards magnetic 
bodies, may also be drawn from experiments then described (2361-68.). 
^ iii. Magnetic characters of Oxygen, Nitrogen and Space. 
2770. The differential action of two portions of gas, or of any two bodies, may, by a 
more elaborate method, be examined in a manner far more interesting and important 
than that just described. The mode of action referred to may even be made the basis 
of instruments, by which, probably, most important indications and measurements of 
both magnetic and diamagnetic actions may be obtained, leading to results which are 
not even as yet contemplated by the imagination. 
2771* If two portions of matter, gaseous or liquid, are tied together and placed in 
a symmetric magnetic field, on opposite sides of the magnetic axis, they will be simul- 
taneously affected. If both are diamagnetic, or less magnetic than the medium occu- 
pying the magnetic field, both will tend to go outwards or equatorially ; equally if 
they are alike, but unequally if they differ. The consequence will be, that, if they are 
placed, in the first instance, equidistant from the magnetic axis, the supervention of 
the magnetic force will not alter their position, provided they be alike ; but if they 
differ, then their position will be changed ; for the most diamagnetic will move out- 
wards equatorially, pulling the least diamagnetic inwards until the two are in such 
new positions that the forces acting on them are equipoised, and they will assume a 
position of stable equilibrium. Now the distance through which they will move may 
be used indirectly, or better still, the force required to restore them to their equidistant 
position may be employed directly to estimate the tendency each had to go from the 
magnetic axis; that is, to give their relative diamagnetic intensities. 
2772. That I might submit gases to such a method of examination, I selected a 
piece of very thin and regular flint-glass tube, about i^ths of an inch external 
diameter, and not more than -^th of an inch in thickness, and drawing at the blow- 
pipe lamp two equable portions of this tube into the shape and size represented, fig. 7, 
in which the barrel part is 1^ inch long, I filled one with oxygen gas and the other 
Fig. 7. 
< 
* Philosophical Magazine, 1847, vol. xxxi. pp. 414, 415. 
