438 F. H. Bigelow — Inversion of Temperatures in 



The temperatures of the United States have been plotted on 

 long rolls, as described in my paper of January (Astron. and 

 Astro-Physics), 1894, for more than 30 periods beginning 1892, 

 Jan. 18*06, and continuing to date, and including the sixteen 

 districts into which the synopsis of temperatures was subdi- 

 vided, the Yuma district not participating in these changes. 

 The time of the eastward movement from the origin, to the mean 

 geographical position of the district to which the last station 

 included in the group gives the name, is as follows in days and 

 tenths of a day, for three different series of months, in each of 

 which the rate is approximately the same. It will be necessary 

 to say something more regarding the winter and the summer 

 circuits of the movement, in a later section of this paper. 



Eastward movement of the Temperature Waves of the United 

 States from the position, Long. 115° W. Tat. 55° JV. 



April, 















December, 



May, 









Mean 







January, 



June, 



September, 





Name of 



Longi- 



Mean 



February, 



July, 



October, 





District. 



tude. 



Latitude. 



March. 



August. 



November. 



1. 



Roseburg 



122 c 



33' 



46° 



42' 



o-i 



o-i 



o-i 



2. 



Calgary . 



107 



43 



50 



46 



0-3 



0-3 



0-2 



3. 



Salt Lake City, 



109 



7 



44 



59 



0-8 



0-7 



0-5 



4. 



Fort Buford.. 



99 



42 



45 



8 



1-1 



1-1 



0-7 



5. 



Sioux City 



96 



20 



39 



43 



1-4 



1-6 



1-0 



6. 



Tucson 



103 



29 



37 



24 



1-7 



2-0 



1-2 



7. 



Corpus Christi, 



95 



13 



31 



34 



1-8 



2-3 



1-5 



8. 



Saint Louis 



91 



40 



41 



42 



2-1 



2-6 



1-9 



9. 



Duluth 



87 



8 



44 



41 



2-2 



2-9 



2-0 



10. 



Saugeen 



81 



51 



46 



37 



2-4 



3-2 



2-7 



11. 



Port Huron . . 



80 



44 



42 



24 



2-6 



3-5 



2-9 



12. 



Pittsburg 



84 



43 



37 



55 



2-7 



3'6 



3'1 



13. 



New Orleans . 



87 



15 



31 



14 



2-7 



3-7 



3-3 



14. 



Key West ... . 



79 



41 



32 



32 



2-8 



3-8 



3-4 



15. 



Washington .. 



73 



43 



40 



58 



29 



3-9 



3-5 



16. 



Northfield 



67 



51 



45 



58 



2-9 



3-9 



3-5 



Inversion of Temperatures. — In accordance with the method 

 established for reducing all temperature variations to the 

 origin, and using the rates of eastward movement as given in 

 the preceding table, a series of periods, thirty in number, 

 from Jan. 18-06, 1892, to Dec. 1P74, 1893, inclusive, have 

 been thus treated. One hundred and thirty stations, arranged 

 in sixteen groups, were taken and the mean of the 8 A. M. and 

 8 A. M. tabulated. These groups were arranged in four 

 divisions : 



I. Roseburg, Calgary, Salt Lake City, Fort Buford. 



II. Sioux City, Tucson, Corpus Christi, Saint Louis. 



III. Duluth, Saugeen, Port Huron, Pittsburg. 



IV. New Orleans, Key West, Washington, Northfield. 



