STORMS AND WEATHER FORECASTS 7o 



Atlantic ocean. The mortality from tiiis cause amounted to 

 many thousands. 'Die hottest region, as shown by the dark 

 shading, was in the middle ]\Iississi[)i)i and Ohio valleys and the 

 Lake region, where the temperature averaged from six to nine 

 degrees above the normal for each one of the 14 days. During this 

 same {)eriod, strange as it may seem, the temj»erature over the 

 vast Rocky Mountain i)lateau was markedly helow tiie normal, 

 and the cold was not due to altitude, for often we find these 

 conditions geographically reversed. The weather charts show- 

 ing the movements of highs and lows during the period of this 

 abnormal heat are not shown in this i)ai)er. Chart V is sin) ply 

 intended to show graphically the area and degree of the heat. 



For some unexplained n^ason there come, in summer, periods 

 of almost absolute stagnation in the drift of the highs and lows. 

 At such times if a high rest over the southeastern part of the 

 country and a low over tlie northern Rocky Mountain region, 

 there will result what is popularly known as a warm wave, for 

 the air, on account of its sligiitly greater si)ecific gravity, will 

 slowly and steadily flow from the southeast, where the |)r(.'ssure 

 is greater, toward the northwest, where the pressure is le.ss, and 

 receiving constant accretions of heat from the hot, radiating sur- 

 face of the earth, w'ithout any wliirls or eddies to mix the upi)er 

 and lower strata, will fimilly attain a temperature almost un- 

 bearable to animal life. This superheated condition of the lower 

 stratum in which we live continues until the low-pressure area 

 in the northwest begins to actively gyrate as an eddy and move 

 eastward, mixing in its course strata of unequal tern [)eratu res. 

 and precipitating the cool and welcome thunder-showers. 



It is a pertinent inquiry whether such adjacent areas of ab- 

 normal heat and abnormal cold can possibly be due to cosmic 

 intluences. The only cosmic influences that meteorology is sure 

 of are the radiation of heat from the sun to the earth and the 

 reception, by space, of the heat that is radiated l)ack by the 

 earth and atmosphere. In the long run, these two balance each 

 other. It is inconceivable that solar insolation, passing out- 

 ward from the sun along true radial lines, could fall so un- 

 equally ui)on the United States as to cause excessive heat on 

 one side and extreme cold on the other. It follows from the 

 ])receding that we must i)e slow to ascril)e any of tiie local pecu- 

 liarities that are observed in terrestrial weather to cosmic inllu- 

 ences. Weather variations, irregular, annual, and diurnal, all 

 probably have their causes at the earth's surface (»r in liu- rartb's 



