8i2 THE POPULAR SCIENCE MONTHLY. 



exemplified at the winter seaside resorts on tlie south coast of 

 England, where certain spots enjoying conditions of shelter from 

 cold winds, combined with exposures favoring the concentration 

 of the sun's rays and the warm winds upon them, enjoy a spring- 

 like mildness through much of the winter. Prof. W. Mattieu 

 Williams * speaks of Torbay, Torquay, Broadstairs, and Hastings 

 as possessing these characteristics. A considerable difference has 

 been noticed in the winter temperatures of places east and west of 

 a certain point on the coast, though all are nearly in the same 

 latitude. 



Dr. D. Hart Merriam has described a succession of tempera- 

 ture zones in descending from the plateau level to the bottom of 

 the Colorado Canon equivalent to those stretching from the conif- 

 erous forests of northern Canada to the cactus plains of Mexico, 

 with marked variations of climatic conditions under apparently 

 very slight diversities of exposure. 



A variation of only 5'3° Fahr. in the mean annual temperature 

 at Uskfield, England, is shown by Mr. C. Leeson Prince f to be 

 sufficient to exert an enormous influence on the general character 

 of the seasons, the produce of the soil, and the health of the pop- 

 ulation. 



The fact of changes in climate being admitted, discussion turns 

 upon their extent, and the laws by which they are governed. In 

 many cases they are brought about by changes in local conditions, 

 of which the removal or replacement of forests, or the relations 

 of land and water, are among the most important. In other cases 

 a periodical law is supposed. The attempt has been made by 

 some meteorologists and astronomers to show that there is a con- 

 nection between such changes and an eleven-year period of abun- 

 dance and scarcity of sun-spots. It was believed by an observer 

 in Ceylon in 1872 J that that island was on the eve of an impor- 

 tant change of climate depending upon a cycle of thirty or thirty- 

 five years. The previous thirty years, he asserted, had shown a 

 complete contrast to the thirty years preceding them, with mani- 

 festly different effects on animal and vegetable life. It had been 

 a period of relatively lighter rainfall, and the next cycle of thirty 

 years was expected to be, above the average, wet. This theory of 

 changes by thirty or thirty-six years is often met in following the 

 discussions on this subject. A paper published recently in the Ar- 

 chives des Sciences Physiques et Naturelles * deduced from a total 

 of twenty thousand years of observations, at about five hundred 

 stations, that the climates of all the continents, excepting only a 

 few maritime coast regions, were subject to simultaneous varia- 



* Popular Science Monthly, March, 1886. J Nature, vol. v, p. 412. 



f Nature, vol. xx, p. 419. * Ciel et Terre, January 16, 1889. 



