132 Terrestrial Magnetism . 
year 1827 by the well-known Humboldt; and by the 
year 1830 the plan was definitively arranged. Stations 
were established at Berlin and Friberg ; and the 
Imperial Academy of Russia entering with zeal into the 
project, the chain of observation was carried over the 
whole of that vast empire. The plan arranged was that 
7 terms should be kept in each year, at intervals of an 
hour for the space of 44 hours. Subsequently, in 1834, 
M. Gauss, the Professor of Natural Philosophy in the 
University of Gottingen, turned his attention to the 
subject; and having, with great skill, contrived some new 
instruments for the purposes of observation that were 
capable of yielding results of an accuracy never before 
imagined to be possible, he found at the very outset that 
the simultaneous occurrence of the perturbations which 
M. Arago had discovered was not confined to the larger, 
or more violent disturbances (the magnetic hurricanes, as 
Humboldt justly styles them), but that even the most 
minute changes at one place had their counterpart at 
another place of observation ; and on tracing the results 
of some term days kept at different places, with simul¬ 
taneous observations made at short intervals of time,, 
the movements of the needles at the different places 
corresponded so exactly with one another as quite to set 
at rest all doubt of their synchronism. The subject 
increasing daily so much in interest, and the attention of 
the continental philosophers being drawn to it by the 
pleasing results of M. Gauss’s investigation, magnetic 
stations were fixed at twenty-three different places, some 
of which are still in operation, in concert with those that 
have been more recently established. 
Sufficient had, therefore, been done in all probability 
to set the matter at rest, as far as the Continent of Europe 
was concerned ; but it became desirable for the completa 
elucidation of this question that a similar plan should be 
