502 Sir Norman Lockyer and Dr. W. J. S. Lockyer. [June 14, 



practically the whole Indian area exhibit variations from year to year, 

 which present very similar features, but that this is the case with 

 other large areas. Thus, for instance, it is found that the yearly mean 

 pressures for Brussels, Bremen, Oxford, Valencia, and Aberdeen (the 

 only pressures that have been at present examined) are all remarkably 

 similar in their variations from year to year, and it might almost be 

 said that one curve, representing the variations from the normal, would 

 approximately define the pressures at all these places. 



The probable extra-terrestrial origin of these short-period variations 

 led to a detailed examination of the records of the phenomena con- 

 nected with solar spots and prominences, with a view of seeing whether 

 similar variations, indicating changes" in the solar activity, could be 

 detected. 



5. A preliminary reduction of the Italian observations of promi- 

 nences observed on the sun's limb since 1871 was first undertaken. 

 The result of this inquiry indicates that, in addition to the main epochs 

 of maximum and minimum of prominences, which coincide in time with 

 those of maximum and minimum of the total spotted area, there are 

 prominent subsidiary maxima and minima having a similar short period 

 and also coinciding in time. (Fig. 1, Curve E.) 



6. Although these subsidiary prominence pulses are not distinctly 

 duplicated in the curve representing the spotted area of the solar 

 surface, it is to be noted that corresponding pulses are indicated in 

 the curves which represent the change of latitude of spotted area from 

 year to year ; and in each case an increase in prominence activity is 

 associated with a decrease of latitude of the spotted area. (Fig. 1, 

 Curves C and D.) 



r 7. A comparison of these solar data with those already referred to 

 relating to terrestrial pressures suggests that these simultaneous out- 

 bursts of prominences and changes of the latitudes in which the spots 

 occur about every 3 J years are the true cause of the pressure changes : 

 and that the varying intensitv of solar activity during the sunspot 

 period of 11 years produces an effect on the pressure and circulation 

 of our atmosphere, thus affecting the whole globe meteorologically. 



^ 8. The close correspondence between the epochs of these subsidiary 

 pressure variations and those representing prominence frequency, 

 suggests not only their very close relationship, but that the terrestrial 

 pressure quickly answers to the solar changes, while so far as the work 

 has gone it would appear that rainfall (fig. 2, Curves A, B, C, D) and 

 snowfall are subsequent effects. . 



9. It may be remarked that we have already obtained evidence 

 showing that this short-period variation is not the only one acting, 

 but that the 11-year and 35-year periods apparently influence the 

 short-period variations ; but even this does not explain some anoma- 

 lies already met with, and should the solar origin of these short-period 



