148 ~— Lovering on Magnetic Observations at Cambridge. 
come from the advice of learned societies and the patronage of 
government. 
Any conclusive inference drawn from the phenomena at one 
place before they have been compared with contemporaneous ob- 
servations elsewhere, made with the same kind of instruments, 
would be unsafe, and might be prejudicial to the truth. Still, 
an early publication, besides being the best mode of making 
what it contains generally accessible, may be of service in en- 
larging the experience of observers, and pointing out modifications 
in the system to be hereafter pursued. With a view, probably, 
to some such object, and in anticipation of a more comprehen- 
sive work at last, Colonel Sabine has recently published, in the 
name of the British Government, the observations which have 
been made at several of the magnetic stations during days of 
unusual magnetic disturbance. The period included is between 
March, 1840, and January, 1842. These extraordinary derange- 
ments in the earth’s magnetism constitute that residual portion 
of the whole force which stands out after the periodical and 
secular changes have been compensated or eliminated. They 
may very properly, therefore, be separated from the regular 
changes, and become a distinct object of investigation. Perhaps 
they are destined, at a future time, to present an experimentum 
crucis of a just theory of Terrestrial Magnetism, induced from 
the ordinary facts of the science, and developed into some 
such remarkable consequence as a magnetic hurricane. A com- 
parison of observations made at the different stations shows that 
a magnetic storm, although it may commence later, or be felt 
longer or more violently, at one spot than another, has the range 
of the whole globe for its play-room, and manifests itself, beyond 
doubt, in the most distant parts of the planet at the same 
