SUNSPOTS AND WEATHER. 513 



do the variations of the sunspot records. As yet, the number of years 

 in which a continuous account of the prominences has been kept is too 

 small to establish any good connection with the long-period or climatic 

 changes on the earth's surface. It was only in 18C8 that Lockyer and 

 Janssen devised a method of observing them at times other than those 

 rare ones when the moon comes in front of the sun's disc and leaves 

 anything protruding from the edge of the latter in plain view for a 

 few seconds. In general, large and numerous prominences are as- 

 sociated with the presence of sunspots, but prominences are frequently 

 observed when no sunspots are visible in their neighborhood. 



While this new method of noting the prominences in preference to 

 the sunspots will probably improve our knowledge of what is going on 

 in the sun, there is some tendency towards a change in the methods 

 of observing the terrestrial atmosphere. The possibility of obtaining 

 observations at heights of 2,000 feet or more above the earth's surface 

 has directed attention to the fact that we are much more likely to get 

 results free from local influences in this way, and perhaps a continuous 

 series of such observations may show better any regular changes in the 

 atmospheric phenomena. At the same time, the opinion has been 

 strongly expressed that the observations already at hand should be 

 sufficient to give the main features of the weather and climate if they 

 can tell anything at all, and that it is time to stop the huge accumula- 

 tion of records of temperature, rainfall, etc., and to undertake the 

 thorough examination of those in our possession. There is un- 

 doubtedly great need for this : a plenteous harvest, with perhaps many 

 tares and but few laborers. 



In conclusion, while it is not my purpose to go into the reasons 

 why more or fewer sunspots and prominences should affect our atmos- 

 phere, a few words may be said on the subject in order to counteract 

 a widely spread misconception. Because the sunspots are dark areas, 

 it is supposed — and one sees the statement frequently in the popular 

 prints — that a portion of the sun's heat is screened off and the im- 

 mediate deduction is made that ' cold waves ' are the result. The first 

 idea is very probably the exact opposite of the truth, and there is no 

 theoretical or observed foundation for the second. As a matter of fact, 

 it is generally agreed that sunspots and the associated prominences are 

 evidences of increased activity, and therefore that they should denote 

 a greater instead of a less output of solar heat. The amount of the 

 change in the solar heat from time to time is as yet unknown; in- 

 vestigations in this direction are only in their infancy. Moreover, it 

 is probable that the changes are too small to very materially affect 

 terrestrial conditions, and even if they do so, the nature of the effect 

 is quite doubtful. For example, an increase of heat from the sun may 

 produce increased evaporation from certain water areas of the earth's 



