SKETCH OF STEPHEN J. PERRY. 837 



sphere, on tlie November meteors, and describing minutely the 

 successive phenomena of the earthquake of March 17, 1871. A 

 communication in the second volume sets forth a method of mag- 

 netic surveys of limited districts in which investigators might 

 employ themselves during their vacations, and which he had prac- 

 ticed satisfactorily during two successive vacations. These were 

 probably the survey of the west of France, made in 1868 in com- 

 pany with Father Sidgreaves, and that of the east of France, 

 made in 1869. A detailed account of such a survey made by him 

 in Belgium one autumnal season was communicated to the Royal 

 Society, with the magnetic elements of twenty stations and the 

 secular variation. Other studies on this subject are recorded ; 

 one comparing the curves as shown by the photographs in terres- 

 trial magnetism at Stony hurst and Vienna, which was spoken of 

 as remarkable in that the curves offered a striking illustration 

 of the simultaneous action of the disturbing forces of two mag- 

 nets many miles apart ; and observations by him and Prof. 

 Balfour Stewart on the regular fluctuations of declination at 

 Stonyhurst and Kew, of which the authors remarked that " such 

 fluctuations almost always occur as couplets or groups of coup- 

 lets a. couplet meaning first a descent and then an ascent, or the 

 reverse " ; and the paper offered an explanation of the phenomena. 

 A communication on the magnetic storm of October, 1872, calls 

 attention to the importance of observations of such manifesta- 

 tions, in view of the coincidences discovered between them and 

 other important natural phenomena. 



In an address delivered in 1872 or 1873 to the Liverpool Poly- 

 technic Society, after explaining what was known of terrestrial 

 magnetism and remarking upon the observed coincidence of mag- 

 netic disturbances with the passing of earth currents, " their never- 

 failing appearance at all auroral displays, their simultaneous 

 appearance at places the most remote from each other, and their 

 agreement in various periodic features with outbursts of sun 

 spots," were spoken of as most powerful aids to the solution of the 

 problems connected with them ; and he suggested that it was not 

 unreasonable " to expect that some light may be thrown upon the 

 question, if we examine with careful attention the not impossible 

 connection of magnetic storms with solar outbreaks, or with vol- 

 canic eruptions and violent earthquakes, with the variations of the 

 wind, or even with the showers of fallen meteors." Further, he 

 asked, if the connection supposed by certain students between the 

 period of solar spots and the relative position of the planets can 

 be maintained, " if the solar disturbances are in any way due to 

 the combined action of the planets, and these again are found to 

 be coincident with the great perturbations of terrestrial magnet- 

 ism, shall we not be inclined to attribute a wider range to the 



