1863.] 



President's Address. 



27 



(that of actual experiment) formed the object of a long and laborious re- 

 search by Dr. Robinson, the results of which are contained in a paper 

 in our Transactions. In the course of this research. Dr. Robinson had 

 occasion to take careful measures of the positions of all the bright lines 

 visible (and not too weak to measure) in a great number of spectra — those, 

 namely, of the induction discharge passing between electrodes of twenty 

 different metals, as well as graphite, most of which were observed in each of 

 five different gases (including air), and for each gas separately at the atmo- 

 spheric pressure and at the low pressure obtained by a good air-pump. 



On taking an impartial survey of this great assemblage of experimental 

 facts. Dr. Robinson inclines to the opinion that the origin of the lines is 

 to be referred to some yet undiscovered relation between matter in general 

 and the transfer of electric action ; and that while the places of the lines 

 are thus determined independently of particular circumstances, the bright- 

 ness of the lines is modified, according to the special properties of the 

 molecules which are present, through a range from great intensity down 

 to a faintness which may elude our most powerful means of observation. 



By a discussion of the results of the magnetic observations maintained 

 for several years past at the Kew Observatory with an accuracy previously 

 unattained, and by combining these with the earlier results of the observa- 

 tions at the British colonial observatories,! have been enabled to trace and, 

 as I believe, satisfactorily to establish the existence of an annual variation 

 in the three elements of the earth's magnetism, which has every appear- 

 ance of being dependent upon the earth's position in her orbit relatively 

 to the sun. Substantiated by the concurrent testimony of observations in 

 both hemispheres, and in parts of the globe most widely distant from each 

 other, this conclusion furnishes an additional evidence of a cosmical mag- 

 netic relation subsisting between the earth and other bodies of the solar 

 system, and thus extends the scope and widens the basis of sound induc- 

 tion upon which the permanent relations of magnetical science must rest. 



To Dr. Otto Torell, Professor of Zoology in the University of Lund, we 

 are indebted for a communication of much interest, informing us of the 

 progress made by an expedition appointed by the Swedish Government at 

 the recommendation of the Royal Academy of Sciences at Stockholm, to 

 execute a survey preliminary to the measurement of an arc of the meridian 

 at Spitzbergen. The objects of the preliminary survey were to ascertain 

 whether suitable angular points for a triangulation could be found from 

 Ross Island at the extreme north, to Hope Island at the extreme south of 

 Spitzbergen, and to determine on a favourable locality for the measure- 

 ment of a base-line. The result of the first year's exploration has been 

 the selection of stations, on hills of moderate height and easy access 

 from the coast, for nine triangles shown in the sketch accompanying Dr. 

 Torell's paper, including Ross Inland in the extreme north, and extending 



