MADE AT MARIETTA, OHIO. 



37 



will not indicate its peculiar temperature; an interval of half a day or a day, 

 however, after a change of wind is sufficient, and the temperature difference (from 

 the tabulated values) of each of the 8 winds has been set down whenever the record 

 of the direction shows no change during two days or more. The record of the 

 years 1829-30-31-32-33-34 and 1847-48-49-50 was exhausted, and that of 1840- 

 41-42-43-44-45-46 partially, to obtain the requisite number of comparisons. For 

 the Directions E. and N. E., single days on which these winds blow, had to be 

 included in the comparison. The total number of days of comparison of tempera- 

 ture and direction of wind is 2340, with the following results : — 



Effect of the Direction of the Wind on the | 



Temperature. 





+ elevation above normal. — depression below normal value. 1 



Direction. 



Half year including 



Tear. 







Summer. Winter. 





■ N. 



— 4°.5 



— 4°.0 



—4°. 3 



N. E. 



—4.4 



—5.1 



—4.7 



E. 



—2.5 



+2.3 



—0.2 



S. E. 



+0.3 



+3.3 



+1.8 



S. 



+2.7 



+8.8 



+4.9 



S. W. 



+2.2 



+2.3 



+2.2 



W. 



—1.9 



—3.5 



—3.0 



N. W. 



—5.8 



—6.5 



—6.2 



These results show that on the average during the year the elevating effect of 

 the south wind nearly equals the depressing effect of the northwest wind. The 

 southeast, south, and southwest winds are the warm winds, all others being cold. 

 The temperature effect in winter is far more marked than in summer, as shown by 

 the extreme range of effect, which is 15°. 3 in winter, and 8°. 5 in summer. 



In the annexed diagram the dotted circles indicate the normal line of tempera- 

 ture, and the curves, when inside the circle, show the amount of depression, and 

 when outside, the amount of elevation of the temperature by the respective wind 

 indicated. Besides an increased effect in winter, the whole curve appears slightly 

 tilted when compared with the summer curve. 



Diagram M. 

 Ilalf year, including summer. Half year, including winter. 



