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November 15, 1860. 



Major-General SABINE, R.A., Treasurer and Vice-President, 

 in the Chair. 



In accordance with the Statutes, notice was given from the Chair 

 of the ensuing Anniversary Meeting for the election of Council and 

 Officers. 



David Forbes, Esq., was admitted into the Society. 



The following communication was read : 



I. " Oil the Laws of the Phenomena of the larger Disturbances 

 of the Magnetic Declination in the Kew Observatory : with 

 notices of the progress of our knowledge regarding the 

 Magnetic Storms/' By Major-General EDWARD SABINE, 

 R.A., Treas. and V.P. Received November 15, 1860. 



The laws manifested by the mean effects of the larger magnetic 

 disturbances (regarded commonly as effects of magnetic storms) 

 have been investigated at several stations on the globe, being chiefly 

 those of the British Colonial Observatories ; but hitherto there has 

 been no similar examination of the phenomena in the British Islands 

 themselves. The object of the present paper is to supply this de- 

 ficiency, as far as one element, namely the declination, is concerned, 

 by a first approximation derived from the photographs in the years 

 1858 and 1859, of the self-recording declinometer of the observatory 

 of the British Association at Kew ; leaving it to the photographs 

 of subsequent years to confirm, rectify, or render more precise the 

 results now obtained by a first approximation. The method of in- 

 vestigation is simple, and may be briefly described as follows : 



The photographs furnish a continuous record of the variations 

 which take place in the direction of the declination-magnet, and ad- 

 mit of exact measurement in the two relations of time, and of the 

 amount of departure from a zero line. From this automatic record, 

 the direction of the magnet is measured at twenty-four equal inter- 

 vals of time in every solar day, which thus become the equivalents 

 of the "hourly observations" of the magnetometers in use at the 

 Colonial Observatories. These measures, or hourly directions of the 

 magnet, are entered in monthly tables, having the days of the month 



