— 173 



other, so the extremes of acceleration ^ 

 and retardation of the earth about pe- 'g 

 rihelion happen together. « 



« When the earth advances in its § 

 orbit so as to arrive at perihelion at its ^ 

 mean time, neither too early nor too =£ 

 late, the temperature is in general neither § 

 too high nor too low, but medium» a 



« It will be observed that before | 

 and after the year 1857, taken as a J 

 starting point, similar periods of cold | 

 are produced at intervals of 2 and 3, s 

 10 and 11, 8 and 8 years, that the 

 cold of 1879 appears to correspond to 

 that of 1837, comprising an interval 

 of 42 years, and that this interval re- 

 curs in 1796. 



« In regard to high temperatures, 

 if, as is probable, another heat-wave g 

 should pass over the earth in 1880-11, g 

 then between 1834 and 1881 (a period | 

 of 47 years), there are four periods of 

 high temperature, or on an average a 

 heat-wave every 12 years nearly. 



« As the mean period of heat is 

 every 12 years and the mean period of 

 cold every 8 years, the mean period of 

 temperate weather is every 10 years. A 

 glance at the chart shows that this is 

 so, since there was a mean temperature 

 in 1832, 1842, 1852, 1862, 1872. 



« An examination of the chart shows 

 that the long period of cold through 

 which the world has passed could not 

 be carried far into the year 1880, fior 

 the earth at its last perihelion was only 

 a few hours in advance of the true 

 time, where as in 1879 it was almost 

 49 hours late and in 1878 morethan ^ 

 20 hours early. C 



«In fact in this respect since 1875 | 

 the earth has been very irregular in 

 its movements, and we shall have to go 



*3 



