18 



SOLAR DIURNAL VARIATION 



Tabli 



1V._1;eoil 



\R Sol 



Aii-DiuiiNAL Vaki.m'ion of the Dip between july, 1841, and July, 









1845. A'alues of A9. 





1 





O" 



2 



4 



6 



S 



10 Noon 



14 



16 



18 



20 



221' 



+21.1"' 





— 0.'03 



+0.'15 



— 0.'16 



— 0.'22 



— 0.'19 



+0.'53 +0.'61 !+0.';-i3 



— 0.'30 



— 0.'31 



— 0.'24 



— O.'IB 





Peb'y 



—0.20 



—0.04 



—0.32 



—0.50 



— O.OS 



+0.42 i +0.63 i +0.4O 



+0.20 



—0.22 



—0.11 



—0.13 







—0.27 



—0.15 



—0.28 



—0.46 



+0.04 



+0.48 +0.72 1 +0.38 



+0.01 



—0.08 



—0.16 



—0.23 





April 



—0.47 



—0.30 



—0.41 



—0.39 



+0.18 



+0.91 +0.73 



+0.31 



+0.06 



—0.02 



—0.28 



—0.36 





May 



—0.38 



—0.43 



—0.37 



—0.25 



+0.54 



+0.80 



+0.53 



+0.15 



+0.02 



—0.02 



—0.20 



—0.34 





June 



—0.47 



—0.24 



—0.25 



—0.34 



+0.30 



+0.87 



+0.75 



+0.16 



+0.02 



—0.08 



—0.40 



—0.37 





July 



— o.-ie 



— 0.4S 



—0.37 



—0.15 



+0.43 



+1.00 



+0.83 



+0.24 



—0.04 



—0.14 



—0.32 



—0.45 





August 



—0.57 



—0.47 



—0.44 



—0.35 



+0.47 



+1.22 +0.92 



+0.13 



—0.07 



—0.03 



—0.32 



—0.46 





Sept. 



—0.63 



—0.43 



—0.54 



—0.66 



+ 0.41 



+1.05 +0.92 



+0.36 



+0.15 



+ 0.04 



—0.33 



—0.39 





Oct. 



—0.23 



—0.17 



—0.35 



—0.45 



+0.25 



+0.64 +0.67 



+0.30 



—0.02 



—0.18 



—0.21 



—0.22 





Not. 



—0.04 



—0.15 



—0.32 



—0.40 



+0.09 



+0.47 ' +0.56 



+0.22 



—0.08 



—0.15 



—0.14 



—0.11 





Deo. 



+ 0.03 



+0.05 



—0.20 



—0.41 



—0.20 



+0.30 



+0.71 



+0.37 



—0.18 



—0.35 



—0.14 



—0.00 





Year 



—0.32 



—0.22 



—0.33 



—0.38 



+0.19 



+0.72 



+0.71 



+0.28 



—0.02 



—0.13 



—0.24 



—0.27 





Sum'r 



—0.51 



—0.39 



—0.40 



—0.36 



+0.39 



+0.98 



+0.78 



+0.22 



+0.02 



—0.04 



—0.31 



—0.40 





Winter 



—0.12 



—0.05 



—0.27 



—0.41 



—0.01 



+0.47 



+ 0.65 



+0.33 



—0.06 



—0.22 



—0.17 



—0.14 





Annual Inequality in the Diurnal Variation of the Dip. — The comparison of the 

 above diurnal variations for summer and winter, with that of the whole year, is 

 given in the following Table. 



Table V. 





O" 



2 



4 



6 



8 



10 



Noon 



14 



16 



18 



20 



22" 



+21.1'" 



Summer 

 Winter 



— 0.'19 

 +0,20 



— 0.'17 



+0.17 



— 0.'07 

 +0.06 



+0.'02 

 —0.03 



+0.'20 

 —0.20 



+0.'26 

 —0.25 



+0.'07 

 —0.06 



— 0.'06 +0.'04 

 +0.05 —0.04 



+0.'09 

 —0.09 



— 0.'07 

 +0.07 



— 0.'13 

 +0.13 



The tabular quantities are exhibited in diagram A. 



(A). Semi-Annual Inequality in the Diurnal Variation of the Inclination. 

 +0.'28 

 .24 



0" 2 4 6 8 10 g 14 16 18 20 22 24'> (+21.1"') 

 Philadelphia mean time. 



