120 Remarhs on Professor Hansteen’s 
even at the same hour, in places very distant from each other.. 
Its westermost position is reached in Iceland and Greenland, 
^at from eight to 10 in the evening ; in Europe and the Ameri- 
can United States, from two to three in the afternoon ; in Su-. 
matra about seven in the morning, in St Helena about eight. 
Its eastermost position is attained in Europe and North Ameri- 
ca about seven or eight in the morning, in Iceland and Green- 
land about nine or ten ; in Sumatra about five in the evening, 
at St Helena, about six (or two). On the north-west coast of 
America, the westermost position seems to occur in the fore- 
noon, the eastermost in the afternoon. 
Those daily oscillations, in fine, appear to consist of four 
movements, two directed eastward, two westward. During the 
continuance of the aurora borealis, the intensity of the earth’s 
magnetic force seems to grow weaker, for which reason the 
needle recedes from that magnetic pole where the ring of the 
aurora is displayed.” 
The facts now glanced at on the subject of terrestrial magne- 
tism, are calculated to inspire an active curiosity as to their 
origin. Nearly all of them shew symptoms of a metallic nu- 
cleus existing in the earth’s interior, over which the magnetic 
virtue is diffused, according to certain obscure and complicated 
laws. Mr Hansteen has successfully demonstrated the incon- 
sistency of supposing with Euler, that one magnetic axis is 
sufficient to account for all : but whether the hypothesis of two 
magnetic axes shall be found more agreeable to nature, is not 
so easily determined. And, at all events, the question concern- 
ing the cause of their movement will even then be as far from 
a solution as ever. Halley’s conjecture assigning a motion to 
the nucleus itself, was not only highly improbable, but also in- 
applicable to the facts : and as we naturally suppose the nu- 
cleus to be immoveable, it appears most rational to seek the 
operating principle in something exterior to the earth. Mr 
Hansteen inclines to refer this agency to the sun and moon, as 
the bodies which lie nearest to us, and produce the strongest 
impression on our globe. Nor is he without arguments to sup- 
port this opinion. They are grounded on a variety of facts, 
Curious, though not convincing. One of the most singular is 
deduced from the correspondettce of his magnetic periods with 
