A. MATHEMATICS AJsD ASTRONOMY. 



1872, embracino- five revolutions of the sun, have been less 

 numerous than during the four preceding rotations, averag- 

 ing respectively 159 and 261 per revolution. 



2. There has been a corresponding diminution in the num- 

 ber of the spots. 



3. The jets inclined in the direction of the reigning solar 

 current have been less numerous, many being in an opposite 

 direction. 



4. The number of jets turned toward the poles has been 

 292, that of those turned toward the equator 89, while 46 had 

 a double inclination. Of the number 89, the greater part 

 were within thirty degrees of the solar equator. Beyond 

 thirty degrees the jets were almost exclusively turned toward 

 the poles, and it is remarkable that the direction of these is 

 opposed to that of the lower portions of the chromosphere. 



Secchi's conclusions resjardino; the connection between so- 

 lar spots and protuberances are especially remarkable. After 

 recountins: the results to which he was led some years as^o in 

 regard to the regions rich in spots and protuberances, and in 

 regard to the heavy metallic and the lighter gaseous jets, he 

 proceeds to state that the metallic jets are those that are 

 connected with the solar spots, and so intimate is this con- 

 nection that whenever he detected the top of one as it came 

 into sio'ht above the eastern limb of the sun, he has been able 

 to safely predict the approaching solar spot at its base. The 

 gaseous or hydrogen jets are not capable of producing spots. 



So familiar has Secchi become with the appearance of these 

 phenomena that he is able, without the spectroscope, and by 

 a simple examination of the physical appearance of the jets, 

 to determine their nature. He finds in the recent observa- 

 tions of Professor Young a complete confirmation of his ow^n 

 view that the spectrum of the metallic protuberances is the 

 spectrum of the interior of the solar spots, the lines being in 

 the one case seen direct and bright, and in the other reversed 

 and dark. On this principle Secchi founds his theory of the 

 constitution and explanation of the phenomena of the solar 

 spots, which are, in brief, according to him, but clouds of 

 cooler metallic vapor pushed up through and floating above 

 the solar photosphere. A more detailed explanation of his 

 views is promised shortly. 6 ^, 1873, 251. 



