Solar Observation. 293 



his phenomena, are such as to invite our most attentive inquiry. 

 To this inquiry peculiar importance has been given of late 

 years by the discovery of an apparent connection between the 

 physical changes in the sun's surface and the electrical condi- 

 tion of the earth, as shown by magnetic variation ; and a field 

 has thus been opened for the most remarkable investigations. 

 Such researches require, indeed, a great amount of perseverance. 

 It was not till after twelve years of incessant attention that the 

 celebrated G-erman observer, Schwabe, succeeded in con- 

 vincing himself of the existence of that periodicity in the 

 development of spots which seems to stand in such mysterious 

 balance with the electrical state of the earth, and, therefore, in 

 all probability, with the conditions of vegetable and animal 

 existence. His investigations were subsequently continued 

 through nineteen subsequent years, and in all, for thirty years, 

 as the President of the Astronomical Society said, in present- 

 ing to him their gold medal, never did the sun exhibit his 

 disc above the horizon of Dessau without being confronted by 

 Schwabe's imperturbable telescope, and that appears to have 

 happened about three hundred days in a year. Nor was that 

 other important discovery of the currents by which the spots 

 are so frequently caused to drift from their places achieved by 

 our own observer, Carrington, without a great expenditure of 

 time and patience. On the other hand, the student who is dis- 

 posed to explore this region of mysteries may remember, for his 

 comfort, that his inquiries will be greatly favoured by the 

 number of available hours during which the object is in sight, 

 as contrasted with the short time allowed for nocturnal obser- 

 vations without encroaching on the natural season of rest, and 

 by the additional chances thus given of intervals of clear sky, 

 as well as by the frequent occurrence of very distinct vision 

 through an amount of haze which would, in the case of less lumin- 

 ous bodies, be an absolute prohibition. This branch, too, of astro- 

 nomical study bears a favourable comparison with some others 

 of the highest interest — for instance, the determination of the 

 periods of binary stars — in the inexpensiveness of the necessary 

 apparatus, and the facility of observation, while a great stimulus 

 to its prosecution may be derived from the opinion of so great 

 an authority as Carrington. Four years of patient investigation 

 have led him to the conclusion that ' ' our knowledge of the 

 sun ; s action is but fragmentary, and that the publication of 

 speculations on the nature of his spots would be a very pre- 

 carious venture." And, in referring to the designs of Schmidt, 

 he says, "he believes that no observer will examine these 

 delineations without finding many characteristic features not 

 satisfactorily explained by any existing theory of the origin and 

 formation of the spots, and without a conviction of the neces- 



