ARCT0W8KI, CHANGES IN DISTRIBUTION OF TEMPERATURE 49 



Table I. — Extreme departures 



Decades "'^'"dlpamires'""^ Difference Mean 



1873-1882 +1.3 -0.4 1.7 +0.45 



1874-1883 +1.3 -0.4 1.7 +0.45 



1875-1884 +1.2 -0.5 1.7 +0.35 



187G-18S5 +1.0 -0.4 1.4 +0.30 



1877-1886 +1.2 —0.4 1.6 +0.40 



1878-1887 +0.8 —0.4 1.2 +0.20 



1870-1888 +0.7 —0.7 1.4 0. 



1880-1889 +0.6 —0.9 1.5 —0.15 



1881-1890 +0.5 —0.9 1.4 —0.20 



1882-1891 +0.5 —0.9 1.4 —0.20 



1883-1892 +0.6 -1.0 1.6 —0.20 



1884-1893 +0.5 —1.0 1.5 —0.25 



1885-1894 +0.6 -0.8 1.4 —0.10 



1886-1895 +0.3 —0.7 1.0 —0.20 



1887-1896 +0.3 —0.6 0.9 —0.15 



1888-1897 +0.5 —0.4 0.9 +0.05 



1889-1898 +0.7 —0.5 1.2 +0.10 



1890-1899 +0.6 —0.6 1.2 0. 



1891-1900 +1.0 —0.6 1.6 +0.20 



1892-1901 +0.9 —0.6 1.5 +0.15 



1893-1902 +1.0 —0.6 1.6 +0.20 



1894-1903 +1.1 —0.8 1.7 +0.15 



1895-1904 +0.7 —0.8 1.5 —0.05 



1896-1905 +0.8 —0.7 1.5 +0.05 



Now, if we take the colimm expressing the highest departures, or 

 crests of the macropleions, we notice a well-pronounced variation of 

 about nineteen years duration. The means of highest and lowest depar- 

 tures also display a difference of about nineteen years between the wann- 

 est decades.^" 



It is interesting to note that a period of nineteen years was advocated 

 long ago by H. C. EusselP^ and recently by William J. S. Lockyer.^* 



The figures of my table are too uncertain to serve as a strong argu- 

 ment in favor of Russell's period. I give them simply to illustrate a 

 method of research which is highly recommendable. 



To sum up the results obtained by the inspection of the maps, I will 

 say that the long-range variations of temperature of particular stations 

 in the United States are due to irregular pendulations of macropleions 

 and macromeions, that these pendulations are complicated by the exist- 

 ence of slight seesaw movements (or vibrations) which increase or de- 

 crease the departures, making the macropleions more or less accentuated, 

 and that, finally, the entire system of macropleions and macromeions 

 m.oves up and down. This last movement is shown on the maps by an 

 increase in size of the macropleions and a decrease of the macromeions 

 or vice versa. This is the real long-range variation. The decade of 



12 The lustra means of the temperature ohserved in New York City demonstrate this 

 variation very clearly. (Am. Geogr. Soc. Bull., Vol. 45. p. 124. New York, 1913.) 



" H. C. Ris.SEr.L : "Meteorological periodicity" (Journ. Roy. Soc. of N. S. W., 1876, 

 p. 151). 



" Solar Physics Committee. A discussion of Australian meteorology, p. 66. London. 

 1909. 



