Wolf, Mitllieilungen über die Sonnenflecken. 57 



Handlung nur folgende drei Stellen hervor: »In tlie year 1779, 

 ihere was a spol od t he sun which was large enough to he 

 seen wilh the naked eye. By a view of it with a 7-fcet re- 

 flector , charged wilh a very high power, it appeared to he 

 dtvided into two parts. The largest of the two, on the 19 ,h 

 of April, measured l' 8", 06 in diameler; which is equal, in 

 length , to more than 31 thousand miles. Both together must 

 certainly have exlended above 50 thousand. « — » It is true 

 that in our atmosphere the cxtent of the elouds is limited to 

 a very narrow compass: hut we ought rather to coinpare the 

 solar ones to the luminous decompositions which lake place 

 in our aurora borealis , or luminous arches, which extend much 

 farther than the cloudy regions. The density of the luminous 

 solar elouds, though very great, may not he exceedingly more 

 so than that of our aurora borealis. For, if we consider what 

 would be the hrilliancy of a Space two or three thousand mi- 

 les deep , fillcd with such corruscations as we see now and 

 then in our atmosphere, their apparent ihtensity, when vie- 

 wed at the distance of the sun , might not be much inferior 

 to that of the lucid solar fluid.« — »The sun lurns on ils axis. 

 So does Üie slar Algol. So do the stars called ß Lyrae, d 

 Cephei , -q Antinoi, o Ceti, and many more; most probably 

 all. Froni what other cause can we so probably aecount for 

 their periodical changes.? Again, our sun has spots on its 

 surface. So has the star Algol; and so have the stars already 

 named; and probably every star in the heavens. On our sun 

 these spots are changeahle. So they are on the star o Ceti; 

 as evidenlly appears from the irregularily of its changeahle 

 lustre , which is often broken in upon by accidental changes, 

 while the general period continues unallercd. Tlie same litlle 

 deviations have been observed in other periodical stars , and 

 ought to be ascribed to the same cause.« — Von speziellen 

 Fleckcnbeobachtungen th eil t Herschel, ausser denen von 1779 

 April 19., nur von 1792 Aug. -26., Sept. 2., 9.. 11., 22.; 17M 

 Sept. 28., Oct. 12., 13., Nov. 20. mit. Vol. 91. (1801.) Her- 

 schel, Observations tending to investigate the Natura of the 

 V. i. 7 



