144 A. D. Biche on Magnetical Observations in Maine. 
AwnvaL JNEQuaLity In THE Diurnat Raver, 
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CaohrONnNe O- Bw B 
Bae, aS Lae | 
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The diurnal range eee a maximum in August and a mini- 
mum in December. There is reason to suppose that the curve 
is a compound one, consisting of two waves, changing its 
character ae to changes in epochs and amount of these 
component sy 
pochs: of poec diurnal deflection—The average epochs of 
the morning east elongation and the afternoon west elongation 
are given in the following table: 
East j East West 
fie partie ionseciall Elongation. Elongation. 
R. M. H. M. iH. M. H. M 
Jan., 8 30 x20 July, 7 20 00 
Feb,, 8 40 1 6&0 Aug., 1 50 0 20 
Mar., 8 20 1 10 Sept., 7 30 0 50 
Ree 88 BO PS 101 Oct 7-30 Sek we 
May, 77 70 0 20 Nov., 8 00 1 00 
June, 6 50 0 40 Dee., 9 00 1 00 
For the summer half year from April to Se sane gains 
the morning east elongation occurs at 74 20™, a r the winter 
half year from October _to March metaded, "ihe east elongation 
west elongation occurs at 05 40m, snd for the winter half year at 
1 20". At Philadelphia these epochs were 1 8m and 15 25™ 
respectively. On the average Pe the year, the turning epochs 
are 74 50™ A. M., and 14 0m p 
Mean monthly values of the dination, observed at Eastport 
between August 1860 and July 1864. 
These ins were obtained as ate Let D, = ici of 
daily minimum and maximum declination, D,,= mean of all 
half hourly dee ination between these osseous and palo 
them, then D= DtD, +C, where C = correction to refer the 
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