Oh. XIII] 



SOLAR MAGNETIC EEEIGB& 





star could not take place consistently with the preservation 

 of the motion of the earth about the sun, according to its 

 present laws. 



Suppose our sun should approach a star within the present 



me. That planet could no longer remain a 



Nept 



member 



planets would be disturbed in a degree which no one has ever 

 contemplated as probable since the existence of the solar 

 system. But such a star, supposing it to be no larger than 



t 



send to the 



emit the same 

 th much more 



the heat which she derives from the sun, and would therefore 

 produce only a very small change in terrestrial temperature.* 



Solar maanetic veriods and variable splendour of the stars. — 



on the sun 



spots 



Schwabe observed in 1852, that the 

 alternately increase and decrease in the course of every ten 

 years ; and General Sabine has pointed out that this variable 

 nW-nva-tio-n rtoinftides in time, both as to its maximum and 



minimum, with Changes in all those terrestrial ma 



7 CD 



variations which are caused by the sun. 



Hence 



infers 



in 



the 



case, we 



naturally 



some 



may 



said 



period. Assuming this to be 

 enquire whether the variable light of 

 connected with stellar magnetic periods, 

 that, hitherto, observation has failed to prove that there is 

 the slightest variation in the light and heat of the sun coin- 

 cident with an increase in the number and magnitude of the 

 spots. In May 1866, there was a temporary outburst of light 

 in a star in Corona Borealis, causing it to become as brilliant 

 as a star of the second magnitude. In twelve days it declined 

 to the brightness of a star of the eighth magnitude. The 

 light was submitted by Mr. Huggins and Dr. W. A. Miller 

 to the test of spectrum analysis, and the result of the ex- 

 periment seemed clearly to indicate 



gaseous 



source, and was produced 



) star in combination with some other element, t 



that the light had a 

 hydrogen burning 



* Quart. Journ. Geol. Soc. 1852. 



p. 62. 



>/ 



f W. Huggins, F. E. S., Quart. Journ. 

 of Science, July 1866. 



