Yearly "Variations of Terrestrial Phenomena and Solar Activities 17 



however be better postponed till the similar investigations have 

 been made with respect to the monthly variations of pressure and 

 temperature. 



From the results of the present investigation, we may suggest 

 the folio wings at least as a kind of working hypothesis: 



1) The 3^early mean temperature of atmosphere, averaged 

 throughout the entire air column above the surface, represented as 

 a function of the geographical position and of the solar activity, 

 contains a leading term of the form F(<p)I)(d), where i^is a periodic 

 function of the angular distance <p from a pole situated somewhere 

 in the northern part of Siberia, and D is also a periodic function of 

 the specific hemispherical difference of solar activity, denoted here 

 by 3 =\N—/S\ I (N-{-S). /^expanded in terms of zonal harmonics 

 will contain a term of the fourth order as a conspicuous member. 

 D seems to be an even function of S. 



2) The pressure is chiefly determined by the temperature of 

 the entire air column. 



3) If F((p) is sheerly determined by the distribution of land 

 and water on the earth's surface, we may regard Z) as an expres- 

 sion of the solar radiation as a function of d. This idea harmo- 

 nizes with the fact that most of those stations in which low 

 pressure corresponds to the low temperature lie in the ' water- 

 zone ' while the contrary is the case in the ' land-zone '. It seems 

 that the radiation is minimum for ^=0, increases at first with 3 

 and attains 'a maximum, for a moderate value of 'that quantity, 

 beyond which it again decreases. 



These ideas which seem to be so far plausible for explaining 

 the facts found, may be useful for planning a farther researches. If 

 the above conjecture be confirmed by future studies, the physical 

 interpretation of the function I)(â) will not fail to form a problem 

 of some significance in the domain of the solar physics in general. 



in. other IVleteorological Elements. 



After the remarkable relations between the atmospheric 

 pressure and temperature and the solar activity has been disclos- 



