attraction of this bulb of oxygen, containing only 0.117 of a grain
of the gas, at an average distance of more than an inch from the
magnetic axis, is about equal to the gravitating force of the same
amount of oxygen as expressed by its weight.

These facts could not rest for an instant in the mind of Faraday
without receiving that expansion to which I have already referred.
'It is hardly necessary,' he writes, 'for me to say here that this
oxygen cannot exist in the atmosphere exerting such a remarkable and
high amount of magnetic force, without having a most important
influence on the disposition of the magnetism of the earth, as a
planet; especially if it be remembered that its magnetic condition
is greatly altered by variations of its density and by variations of
its temperature. I think I see here the real cause of many of the
variations of that force, which have been, and are now so carefully
watched on different parts of the surface of the globe. The daily
variation, and the annual variation, both seem likely to come under
it; also very many of the irregular continual variations, which the
photographic process of record renders so beautifully manifest.
If such expectations be confirmed, and the influence of the atmosphere
be found able to produce results like these, then we shall probably
find a new relation between the aurora borealis and the magnetism of
the earth, namely, a relation established, more or less, through the
air itself in connection with the space above it; and even magnetic
relations and variations, which are not as yet suspected, may be
suggested and rendered manifest and measurable, in the further
development of what I will venture to call Atmospheric Magnetism.
I may be over-sanguine in these expectations, but as yet I am sustained
in them by the apparent reality, simplicity, and sufficiency of the
cause assumed, as it at present appears to my mind. As soon as I