5)0 GAUSS AND WEBER ON TERRESTRIAL MAGNETISM. 



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 aU drawn according to Gottingen mean time, 

 (indicated at the top of each plate,) or at least very neai-ly so, and 

 therefore contemporaneous movements appear all in one vertical 

 line. The order in which the several cm-ves 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 2Sth of November, 1835, and during the following 

 night, the observations at Palermo -^a ere much disturbed by an 

 exceedingly ^dolent 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 Avind appear to be wholly without influence on the magneto- 

 meter, 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 regu- 

 lar and uniforn, progress, has been remarked in the Magnetic 



