$ las] Sun-spots 157 



spots observed by Galilei were the greater darkness of the 

 central parts, some of his drawings (see fig. 55) shewing, 

 like most modern drawings, a fairly well-marked line of 

 division between the central part (or umbra) and the less 

 dark fringe (or penumbra) surrounding it ; he noticed also 

 that spots frequently appeared in groups, that the members 

 of a group changed their positions relatively to one another, 

 that individual spots changed their size and shape con- 

 siderably during their lifetime, and that spots were usually 

 most plentiful in two regions on each side of the sun's 

 equator, corresponding roughly to the tropics on our own 

 globe, and were never seen far beyond these limits. 



Similar observations were made by other telescopists, 

 and to Scheiner belongs the credit of fixing, with consider- 

 ably more accuracy than Galilei, the position of the sun's 

 axis and equator and the time of its rotation. 



125. The controversy with Scheiner as to the nature 

 of spots unfortunately developed into a personal quarrel 

 as to their respective claims to the discovery of spots, 

 a controversy which made Scheiner his bitter enemy, and 

 probably contributed not a little to the hostility with which 

 Galilei was henceforward regarded by the Jesuits. Galilei's 

 uncompromising championship of the new scientific ideas, 

 the slight respect which he shewed for established and 

 traditional authority, and the biting sarcasms with which 

 he was in the habit of greeting his opponents, had won 

 for him a large number of enemies in scientific and 

 philosophic circles, particularly among the large party 

 \\ho spoke in the name of Aristotle, although, as Galilei 

 was never tired of reminding them, their methods of 

 thought and their conclusions would in all probability 

 have been rejected by the great Greek philosopher if he 

 had betn alive. 



Jt was probably in part owing to his consciousness of a 

 growing hostility to his views, both in scientific and in 

 ecclesiastical circles, that Galilei paid a short visit to Rome 

 in 1 61 1, when he met with a most honourable reception 

 and was treated with great friendliness by several cardinals 

 and other persons in high places. 



Unfortunately he soon began to be drawn into a contro- 

 versy as to the relative validity in scientific matters of 



