Arctovjski — Pleionian Cycle of Climatic Fluctuations. 31 



of calcium for example can or cannot take place at the very 

 high tern peratnres of the photosphere ? For my considerations it 

 is absolutely indifferent if the f advise are formed of incandescent 

 dust or of metallic vapors condensed into liquid drops or 

 whether they are simply gaseous vapors. 



Again, another objection may be raised against the concep- 

 tion of the circulation in and around the solar spots that I have 

 adopted. But in this case also, theory has no importance since 

 the fact is that umbrae radiate less heat than the average photo- 

 spheric surface and that faculae seem to radiate more heat. 



Speaking of heat, it would also be preferable to avoid that 

 expression entirely and use the words radiation, or energy, or 

 radiant energy of the sun. 



But all such objections have nothing in common with the 

 fact of the existence of a horme-pleionian variation, a fact 

 which is a result of the Greenwich measurements and of my 

 calculations. And now, in order to establish a theory of the 

 terrestrial pleionian fluctuations, more calculations are neces- 

 sary. 



The first effort to be made is to find out whether 

 atmospheric temperature varies proportionally to the ratio of 

 the faculae and umbrae, or, if such a law cannot be established, 

 because of the complexity of meteorological phenomena, it will 

 be necessary to show at least some striking correlations between 

 the variations of one and the other. Up to the present, a lack 

 of time has prevented me from making more than one single 

 attempt, which has been successful, and I wish to show 

 now how the horme-pleionian maximum of the solar rotations 

 772-781 found its repercussion in the temperatures observed 

 on our earth-surface during the years 1911 and 1912. 



In order to have figures corresponding exactly to the same 

 time-intervals as those of temperature, monthly means of the 

 areas of faculae and umbrae were calculated, for the years 1909 

 to 1913, and then the ratios of the overlapping yearly totals 

 were formed. 



These figures expressed graphically on a diagram show a 

 well-pronounced crest of the horme-pleion corresponding to the 

 mean of June 1911 to May 1912. But before this maximum 

 is reached we notice two steps, one at the mean of April 1910 

 to March 1911 and the other corresponding to the mean of 

 November 1910 to October 1911. In 1912 the ratios decrease 

 till a minimum corresponding to the mean of March 1912 to 

 February 1913 is reached, and from then on the ratios again 

 increase and form the ascending branch of a new horme-pleion. 

 To simplify comparisons, we may call 1911 : 2 the mean of 

 February 1911 to January 1912; 1911:3 that of March 1911 

 to February 1912, and so forth. The figures for 1910:4 — 

 1910 :11, — 1911 : 6 and 1912 : 3 are therefore conspicuous. 



