1870.] DOUGLAS — ON OBSERVATIONS OF THE SUN. 12? 



observes, of one of the most strikiDg of the prominences in the 

 last eclipse — the corn-ear protuberance — that while its peculiar 

 shape has all the appearance of having been impressed upon it by 

 a cyclone, it is in the neighbourhood of a larger sun-spot and a 

 group of fcculsc. As, however, this is the only instance in which 

 he observed any relation between sun-spots and protuberances, he 

 considers their vicinity to one another accidental. Lockyer, 

 however, justly remarks tliat though there may be spots visible in 

 one region without prominences, and prominences without spots, 

 it does not follow that a spot is not accompanied by a prominence 

 at some stage of its life, or that the spot and prominence do not 

 originate through one and the same action. 



Prof. Young, of Hanover, N.H., who is making daily observa- 

 tions on the spots and protuberances, does not admit so intimate a 

 relation between them. From his observations he considers it 

 evident that the spots and prominences obey nearly the same laws 

 in respect to their distribution on the solar surface ; but the 

 prominences, which are far more numerous than the spots, 

 approach nearer to the poles, and are more frequently found on 

 the equator. He has never yet been able to watch a spot in its 

 passage round the limb, so as to observe its efiect on the chromo- 

 sphere ; but his present impression is that certain depressions, 

 observed from time to time in the chromosphere, are due to spots 

 directly under them. In only one case has he found a promi- 

 nence very near a spot, and then only a small one. Whether the 

 prominences are connected with the fecula3, he thinks, is a 

 different question, and more likely to receive an affirmative 

 answer. 



Dr. Curtis remarks that his photographs show abundance of 

 feculae, and prove that there must have been an almost continuous 

 line of thin objects along the portion of the circumference of a 

 great circle of a solar sphere occupied by the protuberances. 



What appears in the telescope as ripples on the surface of the 

 sun — the feculoe — generally occur near a spot, and reveal their 

 presence to the spectroscope by a decided reduction in the intensity 

 of the dark hydrogen lines, and sometimes their conversion into 

 bright lines, even upon the surface of the sun. 



The spectroscopic phenomena of the spot itself are very curious. 

 Of course, deductions have been drawn from them ; but it would 

 be premature to put implicit reliance on them until more extended 

 experiments on gases at different temperatures, and under varying 



