35% Mr. Christie on the diurnal deviations of the 
Taking the whole of the observations, the direction at nine 
o'clock appears to be that from which the evening observa- 
tions vary least : considering then the direction at nine 
o'clock as the zero of each day, we obtain the following 
Table of the greatest Easterly and Westerly Deviations , their times , 
the times of Zero , and the total daily changes in the direction of 
a Magnetic Needle having its North end held in equilibrio, at 
South by two bar Magnets placed in the line of the Dip. 
April 
Max. E. or Plus. 
Zero. 
Max.W. or Minus. 
Total 
change. 
Value. 
Time. 
Value. 
Time. 
Value. 
Time. 
0 1 
h. m. 
0 / 
h. m. 
0 / 
h. m. 
0 / 
20 
+ I 28 
7 55 
0 00 
O 
00 
— I 24 
0 48 
2 52 
21 
+ 2 30 
7 4 ° 
0 00 
II 00 
— I 40 
i 35 
4 IO 
22 
+ 1 4 8 
8 30 
0 16 
10 40 
— I 16 
2 05 
3 °4 
23 
+ 0 34 
8 08 
I 40 
9 00 
— I 30 
1 30 
2 04 
24 
4- 1 16 
7 4 ° 
I 46 
9 57 
~l 52 
1 45 
3 08 
25 
+ ° 54 
7 15 
1 54 
9 47 
— 2 08 
2 00 
3 02 
26 
+0 44 
8 15 
2 52 
9 30 
— 2 32 
1 15 
3 16 
27 
41 08 
8 30 
2 52 
10 06 
— 2 08 
1 00 
3 i 6 
Mean 
+ 1 18 
7 59 
1 25 
10 2 
-I 49 
1 30 
3 6 
The times of the corresponding maxima in the several 
days agree with each other, and likewise with the observa- 
tions at north, as nearly as we could expect, but those of zero 
are more at variance. This however is accounted for by 
considering that this point has been, in some measure, as- 
sumed arbitrarily, in consequence of the gradual change in 
the direction. The mean total changes here and at north, 
likewise agree very nearly with each other, taking into the 
account the difference of the intensities in the two cases ; and 
particularly if we take the means of those observations which 
