DIPPING. 
of the canfe upon which that phenomenon depends, may be 
derived from the fol ee rent. ae 
net, NS, Plate 1V. Magn m, fig. 22 
rella; or a magnetic feel ned N5 . y drawing a 
circle round thelatter, one may eafily be zure to ‘him lf th he form 
of a globular magnet.) ‘I Che extremity N of this silane or 
bar, is - north pole, and the extremity Sits fouth pole ; 
Ra is its middle or equator. P.ace it upon a tbe as 
then pe e another {mall and obloag magnet, or a com- 
mon re rende 5 fufpend i it by fafen- 
h a manner as to remain 
uence 
mall magnet, eee held by the 
the thread, be brought juft over the middle of 
ce ee magne t, withia two or three inches of it ; you will 
find that it will turn itfelf fo as to dire its fouth ‘pole 5 to- 
wards the north pole N of the large magnet, and its cae 
pole z towards the fouth pole S of t e large one; it bei 
well-knowa law in magnetic s, that aie of diffe Biel t den mea 
ai ata sues other, de Alay be fa: ae) cbferved that os 
h 
byt the ei! poles of the large magnet, which are 
Serr fro ormer. But if the fmall magnet be 
moved a little nearer to one end the 
large magnet, then one of the poles a the former, namely, 
that which is neareit to the contrary pole of the latter, wil 
incline itfelf towards it; and of courfe the other extremit 
will be elevated above he horizo This inclination of the 
{mall magnet will be ‘ee to increafe in ie aa as it 
is eee nearer an arer to 0 e pole or S; 
, at laft, if it be beag direétly one ofite to — of thofe 
er it will turn its contrary pole towards it, will place 
ifelf in the fame ftraight ee with the axis 7, the lar 
magnet, as is indicated byt the figures 22 aa 23, wherein the 
like parts are denoted by the fame letter 
- It muft now be obferved, that all ae fats that have hi- 
ats been noticcd relative to the fubje& of magnetifm, i 
to prove, le the whole earth is, or muft be confidered as 
q 
nee ama agnetic needle, or any cther magnet w 
i d on different parts of the earth’s furface, in- 
clin nes, or ae to sncline e, the one or the other of its extrem:- 
‘fe 
o 
© 
Zh 
Pp 
pots 
= 
3 
2 
‘09 
fr) 
> 
er 
2 
oe 
ea 
> 
ao 
oA 
o 
eS 
Len 3 
oO 
ao 
Pe a 
au 
= 
5 
XQ 
o 
bad 
Rac) 
“a 
5 
» 
equator of the earth, it an horizontal fitua- 
tion; that if it be moved nearer to one of the poles of the 
ar t muft incline one of its extremities 5 ; me , that 
u 
laitly, that when brought juft ov either the magnetic 
poles of the earth, it met ftand rependculr to the ground; 
vie. in eed fame ftraight line with the axis of the earth. 
er muft not be oer to hear that a fouth 
eset ifm i is baieeriy to the north pole of the earth ; it 
being only meant, that it has a magnetic polarity contrary to 
that.end of ea. agnetic needie which is direted towards it ; 
and as.we call the fame end of the needie a north magnetic 
by any other - 
en of the {mail magnet are ‘equally at~ . 
ot 
o 
ae we mui of neceffity attribute a ey il that 
a fouth magnetic polarity, to the f the 
earth; viz. it 
muit be confidered as being poffeffed of a no:th magnetic po- 
arity. 
By a little oe rena it will be eafily compre- 
hended, that the true and natural fituation of a magnet, or 
s a combination ‘of its horizontal and verti- 
; . the magnetic needle endeavours to place 
itfelf in the plane of the magnetic meridian, and in a direc- 
tion more or lefs inclined to the horizon, according as it hap- 
ns to be fituated, nearer to or farther trom a ny of the 
a 
ore, in order 
the magnet, the magnetic 
needle, or oblong mapnet, en be placed in the magnetic 
meridian ; viz. in the ufual direétion of the compafs at a 
place of obfervation ; ; otherwife the incination of the ma 
netic pole . 
the magnet is called the sagt line. Theref 
di nvi 
ai be 
or though it foon appeared, that neithe gnetic 
poles, the magnetic equator, of the earth, coincided 
with its true poles and true equator; yet that very fame cir- 
cumitance feemed to furnith the ae re determining the 
longitude; which method was g ots the following 
principle ; viz. that if the magnetic ple hough sapitioe 
from the real ‘ea of the earth, be either fixed i 
places, or do mov 
ftruments were ea eee va 
teacher of t i 
° 
i] 
longitude y place in th rid. Phil. Trans. v. viii. 
p-6065. Mr. Bond was not the only projeftor of the kind. 
Mefirs. Ditton, Whifton,- and many others followed his ex- 
hy 
ample. Some were potitive, otliere doubtful, 
a 
