OF THE ATMOSPHERIC TEMPERATURE. 



317 



The table below contains the deflections from the normal direction of the wind 

 X = 68° at Marietta, Ohio, taken from p. 36 of my discussion of the Meteorological 

 Observations^ at Marietta, made by Dr. S. P. Hildreth. 









I 



2 



3 



4 



5 



6 



7 



8 



9 



1830 



1840 

 1850 



+18 







22 



+ 8 



+ 11 







— 20 



+20 

 — 10 

 — I 



-|-20 

 II 



+ 7 



+13 

 — 12 



+14 

 —23 



+21 

 —35 



+19 



—34 



+ 2 

 —25 











1 



_1B10_ 









1820 









18 



80 









1R 



40 









If 



w 









IRfiO 































































































A 



"\ 













































2' 























/ 



\ 



^ ^ 





k. 







































[,_ 



i 



-a 







"1 



., 



'•\ 









[/ 





,/ 



V 





'*S 



N, 



._ 



^•\ 











/ 



-\ 





_- 



. 



> 







T 





n 





1 





1 



) 



- 



■^ 



\ 



^\ 



u 



^ 













\N 



"s 





\ 



/ 











-•v 







\ 





^ 







1- 



\ 



'S 





p 











\ 



y 



















\ 



A 



V 



/ 





„/ 









\._ 



/^ 



— •'' 



w 







- 



\ 



r 



































\ 



J 

































03 











?0 

















' 



H, 



















































in 



















L 



Vl/ 



V 



/ ^ 



\ 

























- 





( 



■3 











n 



















^- 



\, 



r 



V 





V 



<\ 





r 



\ 







^ 



\ 





/ 











) 



m 











10 

























\ 





f 



\ 



sV 



^ 



\ 



y 



/ 



/■ 



\ 



I 



f 







1 



1 













PO 



















. 







\ 



J 







A 



\ 



> 





/ 



\ 



J 











'^ 













30 





































\ 



/ 





















































































- 







L_ 



























































i 







S 3 



s a 



c 



3 



f The temperature at Marietta closely follows this type. 



To interpret the above diagrams correctly, the true relation between the secular 

 change, as shown by a succession of annual means, of the direction of the wind and 

 of the temperature, will appear with sufiicient distinctness by considering the zero 

 line or axis of abscissse, not as a straight line but as a curve, drawn midway 

 between the two curves; in other words, either the normal direction of the wind is 

 imperfectly made out (through insufficiency or imperfection of observations), or the 

 relation of the mean direction of the Avind to the mean temperature of the air is 

 not constant ; I incline to the former alternative. So far as our evidence goes, 

 for years of northerly (-|-) deflections of the winds, the temperature appears to be 

 lower, and for southerly deflections higher than the normal value. This subject 

 also demands further investigation. 



Enough has been shown to make it evident that for final explanation the secular 

 variations in the temperature, in the rain-fall, and in the direction of the wind must 

 be studied together, and it will probably be found that the former depend directly 

 on the latter, though, ultimately, the deflections in the resulting direction of the 

 wind must be referred to effects of solar radiation; the discussion must take a 

 wider range so as to include long series of records at stations representing all parts 

 of the globe. 



^ Smithsonian Contributions to Knowledge, No. 120 ; Washington, June, IS 



