10 K Loomis — Results derived fror 



Temperature of 1 00° Fahi 





Latitude. 



Elevation. 



ra.e. 



Yankton """ 

 Fort Sully 



i i 



X£ 



ae 



The first three stations, together with the fifth, 



steady decline in the intensity of the heat 

 ward ; but Fort Sully shows tei 

 occur at stations several hundi 

 station the meteorological instn 



walls of the fort, and the thermc 



by heat reflected from dry sand, and stone wall: 

 to be the most probable explanation of tin 

 ported at Fort Sully. 



Bain-areas— their form, movements, distribution, e 

 In order to investigate the form of rain-areas ; the lai 



govern thei 

 curves I selected all tbos 

 months (Sept. 1872 to Nov 

 of rain fell at one statior 



advance north- 

 much greater than 

 mthward. At this 

 located within the 

 influenced 



which 



ind their relations to the isobar 

 o cases during a period of fifteen 

 . 1873) in which at least two inches 

 in eight hours. These cases were 

 men divided into two classes, one containing the stations south 

 of latitude 36°, and the other containing the stations north of 

 latitude 36°. The following table exhibits all the cases which 

 occurred at the southern stations. Column first contains the 

 number of reference, column second shows the day and hour of 

 observation (the numeral one denotes the 7.35 A. M. observa- 

 tion ; two denotes 4.35 P. M., and three denotes 11 P. M.) ; 

 column third shows the station at which the greatest rain-fall 

 was observed; column fourth shows the precise amount of the 

 rain : column fifth shows the height of the barometer at the 

 same station ; column sixth shows the direction and force of the 

 wind at the last preceding observation ; column seventh shows 

 the direction and force of the wind at the date uiven in column 

 second; column eighth shows whether the direction of the 

 winds at the neighboring stations indicated a cycloidal or inward 

 motion ; column ninth shows whether there was any local 

 depression of the barometer ; and columi 

 there was a high or a low barometer o 



given station. 



For a large number of these cases I h: 

 the United States, the curves of equal 

 of an inch. These curves show that 

 principal center of precipitation, the form of th< 

 nearly circular, and its diameter varies from 350 t 



5 Of 





