MAGNETIC FORCE OF OXYGEN GAS. 
27 
not only the place of bodies, but also their relative degrees of force, at the same and 
at different temperatures, with a degree of accuracy that will serve great purposes 
in the further development of this branch of science. 
2792. Amongst the gases hitherto examined there is nothing that compares with 
oxygen. The following are comparatively indifferent by the side of it : — chlorine and 
bromine vapour, cyanogen, nitrogen, hydrogen, carbonic acid, carbonic oxide, olefiant 
gas, nitrous oxide, nitric oxide, nitrous acid vapour, muriatic acid, sulphurous acid, 
hydriodic acid, ammonia, sulphuretted hydrogen, coal-gas, ether vapour and sulphuret 
of carbon vapour; for though some, as olefiant and cyanogen gases, appear to be a 
little diamagnetic, and others, as nitrous oxide and nitric oxide, are magnetic, yet 
their effects disappear in comparison with the results produced by oxygen. 
2793. I hope to give the correct expression of the paramagnetic force of oxygen 
(2783.) hereafter, in the meantime I am tempted to give one or two rough illustra- 
tions of its degree in this place, in addition to the former one (2774.). The capacity 
of the oxygen bulb, containing one atmosphere, is not quite 0'34 of a cubic inch, and 
the weight therefore of the oxygen within OTI7 of a grain. I endeavoured to com- 
pare this quantity in the first place with soft iron, and therefore attached a portion 
of that metal, having one-tenth of this weight or 0’012 of a grain, to a fine platina wire 
fixed into one end of a vessel, corresponding in size to that containing the oxygen, so as 
to bring the iron into the middle, and then the bulb was exhausted and hermetically 
sealed. Being now opposed to the oxygen tube in the magnetic field, it was found, 
as expected, far to surpass the oxygen in magnetic power. As it was inconvenient 
further to reduce the iron or to enlarge the oxygen, another magnetic substance was 
employed for the comparison. 
2794. One hundred grains of clean, good, crystallized protosulphate of iron were 
dissolved in distilled water, and diluted until a glass bulb, of nearly the same size as 
the oxygen bulb when filled with the solution, was equal to the oxygen bulb in force, 
and stood equidistant from the axial line, as far as I could judge by the present 
modes of observation. When the solution had this strength, it occupied the bulk of 
17i cubic inches. As the bulk of the oxygen is only 0‘34 of a cubic inch (2793.), that 
volume of this solution would contain very nearly two grains of crystallized sulphate 
of iron, equivalent to 0‘4 of a grain of metallic iron ; so that, bulk for bulk, oxygen is 
equally magnetic with a solution of sulphate of iron in water containing seventeen 
times the weight of the oxygen in crystallized protosulphate of iron, or 3’4 times its 
weight of metallic iron in that state of combination. 
2795. Again, the oxygen tubes, containing respectively one atmosphere and a va- 
cuum (2780.), were adjusted about an inch apart, and placed on each side of the mag- 
netic axis, and the force of the magnet developed. The oxygen of course approached 
the magnetic axis, and the vacuum passed equatorially. A slender glass filament, 
about 6 inches in length, had been drawn out at the lamp and fixed to a foot ; and 
the end of this filament was then employed to press back the oxygen tube into its 
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