Page:Scientific Memoirs, Vol. 2 (1841).djvu/102

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GAUSS AND WEBER ON TERRESTRIAL MAGNETISM.
November, 1835. January, 1836. July, 1836.
Hague 42·01 63·01 42·01
Göttingen 42·25 63·38 42·25
Berlin 42·24
Breslau 42·40
Leipzig 41·34 63·01 41·34
Marburg 42·20 60·28 42·20
Munich 41·86 55·82 41·86
Milan 40·27 60·40 41·33
Palermo 42·07
Catania 41·56
Messina 43·06

For the three last terms, the value of the divisions of the scale, and the proportion, according to which they have been inserted in the plates, are stated in the table of numerical results.

The curves are all drawn according to Göttingen mean time, (indicated at the top of each plate,) or at least very nearly so, and therefore contemporaneous movements appear all in one vertical line. The order in which the several curves are arranged in each plate was principally regulated by convenience as to the curves fitting into each other.

The following remarks may be added in regard to particular terms:

On the 28th of November, 1835, and during the following night, the observations at Palermo were much disturbed by an exceedingly violent Sirocco-wind, so that at one time they had even to be suspended for an hour and a half; and at other times only partial and uncertain determinations could be obtained. It is probable, therefore, that many of the apparent movements were not real magnetic changes. Nevertheless, we determined not to exclude this curve; as the latter part of it, from the morning of the 29th November, when the storm had nearly passed over, offers a sufficiently satisfactory accordance with the stations to the north. I take this opportunity of mentioning that, according to all our experience hitherto, the most violent storms of wind appear to be wholly without influence on the magnetometer, provided only the instrument is effectually protected from any effect of their direct mechanical action. Very frequently, either an extremely quiescent state of the needle, or a very regular and uniform progress, has been remarked in the Magnetic