( n8 )
is on the eaft or weft fide of the true meridian; andwhere the variation is called eaft or weft in the followingpart of this work, it is to be underftood that the northend of the magnetic needle has eaft or weft variation ac-cordingly, except it is particularly mentioned to the con-trary.
From the table it appears the magnetic needle had eaftvariation in the year 1576; that is, its north end wasii° 15' on the eaft fide of the true meridian of London ;and in 1657 the needle was in dire&ion of the true me-ridian ; and fince that time it has been veering about tothe weft, until it has got upwards of 24 0 to the weft-ward thereof. Befide this annual variation juft mention-ed, it has a daily variation.
I {hall infert a table, fhewing the diurnal variation ta-ken at different hours of the 27th day of June, 1759, byMr Canton .—f Phil. Pranf. vol, 51 .)
Hri.
Min.
O
18
6
4
Morning *
8
9
3 °
2
ro
20
11
40
r
0
5 °
1
38
Afternoon <
3
IO
7
20
9 12
11 40
f.
Declination
Degrees ofbnre/iheifsthermom.
west.
18°
2'
62°
18°
58'
62°
18°
55 '
65°
18°
54 '
67°
18°
57 '
69°
19°
4 '
68f°
19 0
9 '
7 °°
' 9 °
8'
70°
19 0
8'
( 58 °
' T 8°
59 '
C)i°
19 0
6'
5 *>°
18°
5 ■'
57 i°
The
■v
■« -