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VI. A Comparison of the most notable Disturbances of the Magnetic Declination in 1858 
and 1859 at Kew and at Nertschinsk ; preceded by a brief Retrospective View of the 
Progress of the Investigation into the Laws and Causes of the Magnetic Disturbances. 
By Mayor-General Edward Sabine, R.A., President of the Royal Society. 
Received April 28, — Read May 26, 1864. 
Before I proceed to the particular subject of this paper as noticed in its title, it may 
perhaps be desirable to take a brief retrospective view of the advances which have been 
made from time to time in our knowledge of the phenomena of the magnetic disturb- 
ances since they became the subjects of systematic investigation ; and more especially 
since the publication of the Report of the Royal Society in 1840, and the establishment 
of magnetic observatories adopting and pursuing the methods of inquiry founded upon 
the instructions contained in that Report. 
The observations of the German Magnetical Association, conducted by MM. Gauss 
and Weber, which was the immediate precursor of the British observatories, commenced 
in 1834 and terminated in 1841, the first year of the British Observatories. It was 
itself preceded by an earlier German Association, formed in 1828 under the auspices of 
Baron Alexander von Humboldt, having for its object to make a series of strictly 
synchronous observations of the magnetic declination at concerted times at widely sepa- 
rated localities, for the purpose of inquiring into the nature and investigating the laws, 
if laws should be found to reveal themselves, of the apparently casual and irregular 
fluctuations of the magnetic needle which had then recently begun to attract the notice 
of scientific men, as natural phenomena proceeding from and indicating some hitherto 
unknown agency, and as such well meriting systematic investigation. 
Berlin was the centre of the first German Association, as Gottingen was of the second. 
In 1829 and 1830 the Berlin Association had correspondents in very distant parts of the 
European continent, such, for example, as St. Petersburg, Kasan, and Nicolaieff, by 
whom the direction of the declination magnet was observed with great care and pre- 
cision at hourly intervals of absolute time for forty-four successive hours at eight con- 
certed periods of the year ; and to the continuance of these term-observations, as they 
were called, there were added in March 1834 similar observations at . Gottingen, but 
made with greater frequency, viz. at intervals of ten minutes. The intercomparison of 
the hourly observations revealed the general fact that very considerable fluctuations, still 
happening however on days that were apparently casual and irregular, were synchronous 
at all the stations of observation; whilst the ten-minutely observations at Gottingen, 
which had no parallels elsewhere, showed numerous intermediate fluctuations of similar 
mdccclxiv. 2 i 
