306 JEL. Arctowski — About Climatical Variations. 



tudes and inverse under other latitudes. Newcomb discussed 

 the problem anew and practically rejected the hypothesis that 

 the solar cycle is an important factor, while nearly at the same 

 time, Nordman demonstrated in a very elegant manner the influ- 

 ence of the sunspot variation upon the temperatures of the 

 equatorial regions. 



To show more plainly the difficulties of the problem, I have 

 to refer to my own researches published in 1909. 



Considering, for given localities, the series of annual means 

 of temperature, we notice everywhere more or less important 

 fluctuations. The curves expressing graphically the succession 

 of figures show perfectly well-pronounced variations at certain 

 localities differing completely from other variations of other 

 localities. Some curves go down when other curves go up, and 

 the length of time separating the maxima varies from one curve 

 to the other. This shows that it is not possible to discuss the 

 problem of climatic variations with the data of only a number of 

 selected stations. All available data have to be taken into con- 

 sideration and the problem has to be studied geographically. 



The problem of the variations of terrestrial temperature is 

 indeed absolutely similar to the problem of the mean elevation 

 of the surface of the earth crust. The precision gained in the 

 appreciation of the mean elevation of a continent depends on 

 the precision of the utilized hypsometrical maps. The pre- 

 cision of an estimate of the mean depth of an ocean depends 

 on the accuracy of the bathymetrical map ; that is to say, on 

 the number of recorded soundings. 



Now, since in the case of temperature we also have to deal 

 with depressions below the average and elevations above, the 

 knowledge of the extent of these areas, covered by positive 

 or negative departures, is evidently more necessary for the dis- 

 cussion than the figures for some isolated stations, where the 

 temperature conditions may or may not correspond to the 

 average conditions of the surrounding countries. 



The work I have done was the mapping of all the temper- 

 ature data I could obtain for the years 1891-1900. Then, 

 considering the means of the decade 1891-1900 as being quasi- 

 normal values, I have formed for each year and each station 

 the departures from these means. These annual departures 

 having been inscribed on maps, equideparture lines have been 

 drawn. The areas of positive departures (above the mean) 

 have been called thermopleions, the areas of negative depar- 

 tures thermomeions or antipleions. 



The result of the discussion shows that 1900 was a year of 

 predominant thermopleions ; the year 1893, on the contrary, 

 a year of most predominant antipleions. Taking the probable 

 areas into consideration, as well as the probable excess and 



