DECLINATION. 
other books, may, for the fake i oo ea os into 
thofe which have been made lace at different 
times, and shale which have ee — at aud ferent places 
and different times. e thal, in the firft place, ftate the 
obfervations made in ee at different times, 
DireGion of the Magnetic Needle chferved in London at di if 
ferent Tin 
MICS 
Years. Declination. 
158 11° 15/ E 
1612 6 10 
1622 6 ° 
1633 4 5 
1634 4 6 
1657 fe) ° 
1665 I 22 W. 
1666 I 35 
1672 2 30 
1683 4 30 
16902 6 fe) 
1700 8 ° 
1717 10 42 
1723 14 17 
1740 15 40 
1745 16 53 
1748 17 4° 
#7 3° 17 54 
1760 19 12 
1765 20 ce) 
1773 21 o9 
1780 22 Io 
1785 22 50 
1787 23 19 
1790 ae) 39 
179 23 36 
1792 23 44 
1793 23 5° 
1794 23 54 
1795 2358 
1796 24. fo) 
1797 24 o 
1798 2 ° 
1749 24 I 
1800 24. 2 
3801 24 3 
2802 24 6 
1803 24, 769 
ae 24. 8.4 
1805 2 9.8 
180 = aH 8.6 
bei ene: yeh with thofe previous to the year 
i800, that t t to aoa as ed upon ster lefs 
than three ur four minutes ; much on account of the 
imperfection of the inftruments, o na the want of accuracy 
in the obfervers, as for the d Fe times of the year, or of 
the day in which ~ obfervations were taken, which, as will 
prefently appear, occafiona very material difference. An 
it is for this r eafon, principally, that when the declination 
for the fame year is given by different cokaers about the 
fame hae their ftatements feldom agre 
remark which obvioufly occurs in — a 
oe table, is, that when the declination was firit o 
ferved in London, the north end of the needle fto 
a of the me tidian. 
obferved to decreafe, until about the year 1657, 
a it was obferved to proceed towards the weft. ee for 
nto ontinted feries of cbfervations, we cann ren 
oie fay hen the change from eaft to wet ceday took 
place 
Tf we take the number of years eae fince the firk ob- 
fe rvation was made, as ftated in the 
made gene that a ri 
are le tt ae that the declination has reached its ulti~ 
mate limit towards the weit, and that the north end of the 
no certain aad determi thus ftated 
rkable obfervations relative to the annual variation 
f the declination, it will now be neceflary to flate na 
monthly and oe ate The inge- 
n Canton was the o took particular 
care to examine the daily variation a ce 
and an account of his obfervations is contained in oa € jl 
oak of the Phil. Tranf. His ftatement is as follo 
The Declination obferved at diferent Hours of the fame Day. 
June 27th, 1759. 
I 
Hours. Min. | Declin. Weft. f{ Fahr. therm, 
° 18 fe) 62° 
6 4 18 58 2 2 
8 fe) 18 s 
Morniag 7 3 7 3 a 6 
10 20 1 657 69 
Lir 40 19 4 682 
fo 5° | 19 9g 70 
yp Hie bye 
10 I ‘ 
Afternoon ¢ : ac a so | 6 
9 12 | 19 6 59 
Il 40 18 = 51 5TE 
The mean Variation for each Month in the Year. 
January - - 7 8" 
February - 8 58 
Marc - - Ii 9 
April - - IZ 26 
ay - - 130 
June - - 13 2% 
July - - 13 14 
Augu - - 12 1g 
September - - II 43 
ob * - IO 36 
November - - 9 
ecember 
6 58 
Lately Mr. Gilpin made : a grea iangay accurate obfervas 
od on the 
From that time the pects was tions of the fame nature at the apartments of the Royal So- 
nthe ciety, a 
and on account of the diftance of time, it vill be 
Beedle was fouad to point due north and fouth ; aad ison ufeful to compare the mean refult of his obfervations — 
fs) t 
