58 KITE WORK OF THE WEATHER BUREAU 



Decrease of Temperature for Each Respective 1,000 Feet of Altitude 





1,000 

 feet. 



1,.500 

 feet. 



2,000 

 feet. 



3,(100 

 feet. 



4,000 

 feet. 



5,000 

 feet. 



G,ono 

 feet. 



7,000 

 feet. 



8,000 

 feet. 



Mean. 





o 



7.2 

 7.0 

 7.4 



o 



.5.5 

 6.4 

 5.8 



o 



4.8 

 6.0 

 5.2 



o 



4.0 

 5.5 

 4.4 



o 



3.7 

 4.9 

 4.0 



o 



3.7 

 4.3 



3.8 



o 



3.9 

 4.5 

 4.1 







.3.4 

 3.5 

 3.4 



o 



3.0 

 4.9 

 4.0 







4.8 





5.8 





5.0 







A grouping of the stations according to their geogra))hical locations 

 disclosed the fact that the mean rate of temperature decrease with 

 increase of altitude was much greater in the central Mississippi water- 

 shed than in the Upper T^ake region, the central West, or the extreme 

 p]ast as represented l)y the single station at \\'ashington. In the 

 afternoon, however, the differences were veiy small, the maximum 

 being only 0.7 degree per thousand feet. 



The morning, afternoon, and mean results for the various districts 

 are shown in the following tal>le: 



Gradient per Thousand Feet 



District. 



Morning. 



Afternoon. 



Mean. 





o 



3.4 

 5.8 

 4.5 

 4.3 



o 



G.O 



,0.1 



0.4 



5.6 



o 

 .3.6 



< '(Mitral Missi.ssippi 

 I'pper Lake region 

 Central We.«t 





5.8 





4.6 





4.7 







It will he at once remarked that there is a very close agreement 

 between the means for the U[)per Lake region, those for the central 

 We.st, and the grand mean of o.O degrees, as well as a marked defi- 

 cienc}' on the Atlantic Coast, amounting to 1.4 degrees per thou.'^and 

 feet. 



Negative gradients of temperature, or "inversions,'' were (piite fre- 

 quent during the morning hours at a number of the stations, and the}^ 

 of course, bear a direct relation to the amount of cloudiness and the 

 velocity of the wind. At Washington on June 21, 1S98, the tempera- 

 ture at an elevation of 866 feet was 14 degrees higher than at the sur- 

 face, and 10 degrees higher at 1,700 feet. At Dodge Cit)', Kans., on 

 October 23, 1898, there was an inversion of more than 11 degrees at 

 an altitude of over 5,000 feet. As a rule, however, the amount of in- 

 version was less at Dodge City than at Washington on account of the 

 prevailing higher winds at the former place. 



