76 THE SUN. 



(34.) But here comes the strange part of their history. 

 These spots are not permanent marks on the sun's 

 surface. They come and go. They begin as small dim 

 specks ; grow to be great blotches ; and then dwindle 

 away. Sometimes they are large enough to be seen 

 without a telescope, when the sun is near setting or just 

 risen, so as to have its dazzling splendour mitigated by 

 the vapours of the horizon, and admit of being looked 

 at steadily. Many instances of such appearances are 

 recorded, some very remarkable ones, long before the 

 invention of the telescope. Two were so seen by my 

 son, Mr A. Herschel, in London, in November, 1861, 

 who sent me a drawing of them, which I found verified 

 on comparison with a drawing taken from the telescope 

 on the same day, by a very assiduous observer in my im- 

 mediate neighbourhood. 



(35.) Ever since the first discovery of the solar spots, 

 they have been watched with great interest, and it has 

 been ascertained that they do not make their appearance 

 indiscriminately upon every part of the globe of the 

 sun. At or near either of its poles they never appear ; 

 and very rarely indeed on its equator, or on any part of 

 its body beyond the 40th degree of latitude understand- 

 ing that term on the sun in the same acceptation which 

 geographers attach to it on our own globe. They 

 mainly frequent two zones or belts parallel to its equator; 

 bearing very nearly the same relation to that great circle 

 of its sphere whicli the regions on our own globe in 

 which the trade winds prevail, bear to the equatorial 

 region of the earth extending, that is to say, to some 



