1879.] Report to the Committee on Solar Physics. 303 



Y. " Preliminary Report to the Committee on Solar Physics 

 on the evidence in favour of the Existence of certain Short 

 Periods common to Solar and Terrestrial Phenomena." 

 By Balfour Stewart, F.R.S., Professor of Natural Philo- 

 sophy in Owens College, Manchester, and William Dodg- 

 SON. Communicated to the Royal Society at the request of 

 the Committee. Received October 23, 1879. 



1. In a previous report to this Committee (" Proc. Roy. Soc," 

 vol. xxix, page 106) we exhibited a method of detecting the 

 unknown inequalities of a series of observations, and we gave some 

 evidence that the temperature-range and the declination-range at Kew 

 Observatory are both subject to the same short period inequalities, the 

 particular periods investigated being those around 24 days. 



To confirm this evidence we have extended our researches, although 

 in a subject of such magnitude they must still be regarded as of a 

 preliminary nature. In our present paper we investigate after the"' 

 method described in our first report the following ranges : — 



1. Diurnal Ranges of Temperature of Air at — 



a Kew (already given). 

 ft Toronto. 

 7 Utrecht. 



II. Diurnal Ranges of Magnetic Declination including Disturbances 

 at — 



a Kew. 



(3 Prague. j 



III. Sun- Spot Inequalities of the period of 24 days as far as this may 

 be obtained from existing records. 



For the Toronto ranges we are indebted to the kindness of the 

 Council of the Meteorological Office, and of Mr. Kingston, Director 

 of the Toronto Observatory. "We have extracted the Utrecht and 

 Prague ranges from the published records of these observatories, 

 while for the Kew declination-ranges, including disturbances, we have 

 to thank the Committee of the Kew Observatory. 



2. To begin with the Toronto and Utrecht temperature ranges, 

 these have been treated exactly in the way in which we treated the 

 Kew temperature-range, so that it will only be necessary to exhibit the 

 result of our treatment in tables which correspond with Table VI of 

 our previous report. 



