THE INTERNATIONAL WEATHER-SERVICE. 309 



change in parallel cycles, and affect every feature in terrestrial mete- 

 orology." 



But, apart from every aid furnished by cosmic meteorology to that 

 of our individual planet, the extension of the international simultaneous 

 weather-reports will, we believe, ultimately afford the data requisite 

 for approximately forecasting some main features of the seasons. A 

 single example (the great heat of last October on the eastern side of 

 the United States) will illustrate the possibility of attaining in some 

 degree this long-desired object, which, like an ignis fatuus, has eluded 

 the pursuit of men for so many ages. The summer of 1879 presented 

 in North America no strongly marked high pressure ; but after the 

 24th of July the barometric conditions were generally "low," and 

 in the " Monthly Weather Review " for August, the Signal-Service 

 stated : " The bai'ometric pressure, as compared with the means of the 



Chart of Equal Bakoitetric Peessukes during August, in and around North America. 

 (Anows shov) prevailing winds for August.) 



seven preceding years, shows that the mean of the entire country has 

 been abnormally loio." We may compare the atmosphere then resting 

 upon the interior to a vast and fixed dry cyclone, the elongated cen- 

 tral area of which covered the Upper Lake region, and the country 

 stretching northward, probably to the sixtieth parallel of latitude — the 

 whole extent of the depression not less than 1,500,000 square miles, 



