14 moleswokth’s pocket-book
CORRECTION FOR LATITUDE.
Positive from 0° to 45°; Negative from 45° to 90°.
Latitude.
Apparent Altitude. 0° 90° 10° 80° 20° 70° 30° 60° 40° 80° 40°
feet. feet. feet. feet. feet.
1,000 2’6 2-5 2-0 1’3 •5
2,000 5-3 5-0 4-1 2’6 •9
3’0(J0 7-9 7-5 6-1 4-0 1-4
4,000 10-6 10-0 8-1 5-3 1*8
5,000 13-2 12-4 10-1 6-6 2-3 0’
6,000 15-9 14-9 12-2 7-9 2-8 lQ
1,000 18-5 17-4 14-2 9-3 3’2 u
8,000 21-2 19-9 16-2 10-6 3-7 <2
9,000 23-8 22-4 l«-3 11-9 4*1
10.00U 26-5 24-9 20-3 13-2 4 • 6
11;000 29-1 27-4 22’3 14-6 5-1
12’000 31-8 29-9 24-4 15-9 5*5 8
13’000 34-4 32-4 26’4 17-2 6’0
14,000 37-1 34'9 28’4 18-5 6*4 &
15,000 39-7 37-3 30-4 19-9 6-9
16,000 42-4 39-8 32-5 21-2 7-4
IT'OOO 45-0 42’3 34’5 22-5 7-8
18,000 47-7 44-8 36'5 23-8 8-3
19,000 50-3 47-3 38-6 25’2 8-7
20,000 1 53-0 49-8 40-6 1 26-5 9*2
Diubnal Baiu,metric Wave.
The period of the wave varies according to the season from
January, maximum 9 p.m. and 10 a.m. •
to June ...................11 r.M. „ 9 a.m.
January, minimum 3 f.m. „ 5 a.m.
to June..............5 p.m. „ 3 a.m.
In the Tropics there is but little variation of period, the
average being
Maximum, 10 f.m. and 9.30 a.m.
Minimum, 4 p.m. ,, 3.30 a.m.
The intensity of the wave varies with the latitude.
At the level of the sea the average intensity in inches being
at sea-level from -09 to -12 inch, and diminishing gradually
to 0 about 65° or 70° north latitude.
The intensity decreases with the elevation above the level
of the sea.