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Terrestrial Magnetism . 
the earth’s surface; and, in the voyages of Sir John 
Franklin and Sir Edward Parry, continuous observations 
were made in very high northern latitudes on all the 
phenomena connected with Terrestrial Magnetism, from 
which the position of the north magnetic pole was ap¬ 
proximately deduced; and subsequently Captain James 
Ross, the Commander of the Antarctic Expedition, 
actually reached the spot of that pole, and had the 
honour of planting the British flag thereon. He is now, 
as this Society is aware, exploring the unknown regions 
of the south, where it cannot be presumptuous to foretell 
he will reap fresh laurels, and haply re-plant that veteran 
symbol of England’s dominion and glory on the Austral- 
magnetic pole. 
Various other facts, equally important to the science, 
were established during these Arctic voyages, tending in 
no small degree to raise it to its present high rank of 
importance. Amongst these may be mentioned the 
phenomenon of the Aurora Borealis , causing evident 
disturbances of the needle; a fact which was long main¬ 
tained by Sir John Franklin even against some high 
authorities, and which is now established beyond a doubt. 
In the year 1818, M. Arago at Paris commenced a 
valuable and extensive series of observations upon the 
changes of the declination; and M. Kupffer at Kasan 
having at the same time undertaken a similar research, 
it was discovered, on comparing the results, that the 
perturbations of the magnetic needle were synchronous 
at the two places, although at a distance from one another 
of more than 47° of longitude. This appears to have 
been the first recognition of a phenomenon which excited 
much attention. To pursue it successfully it was neces¬ 
sary to extend and vary the stations, adopting in them 
all a common plan of observation. Such a system of 
simultaneous observation was, in fact, organized in the 
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