Experiments and Obfernsatiom. 65 
of horfe-hair, confifting of five or fix links, to which the 
needle was fufpended. Each link is about three-quarters hf an 
Inch in diameter ; and the extremities of each piece of hair, 
which is formed in a ring, are joined by a knot, and fecured by 
a little fealing- wax. The link on one end of this chain is 
fufpended to a pin in a proper frame, or any fupport that may 
be at hand ; and to the link of the other extremity which lies 
lower mo ft, a piece of fine filver wire is hooked. This wire is 
about an inch and a half long, and its lower extremity is 
fattened round a final! and cylindrical piece of cork, through 
which a common fewing needle, made magnetic, is thruft 
horizontally. Thus the magnetic needle is fufpended by a 
hair-chain, the links of which, on account of the fmoothnefs 
and lightnefs of the hair, move very freely in each other, and 
allow the needle more than a whole revolution round its centre, 
with fo finall a degree of fri&ion as may be confidered next to 
nothing. By comparing this needle with others of the beft 
fort in ufe, I find the former to be much more fenfible ; for 
when bodies which have an exceedingly fmall magnetic power 
are tried, this needle will be frequently attracted by them when 
the others are not fenfibly attested. 
In order to try farther the delicacy of fuch fufpenfion, I 
placed a piece of looking-glafs under the needle, and nearly 
horizontal, fo that the image of the needle was feen in it. 
Now, as a fine line had been previoufly marked on the glafs, 
things were fo difpofed as that the image of the needle might 
coincide with the line marked oh the glafs, the eye being placed 
in a proper point of view; afterwards, by ftiaking the needle 
either very gently or very quickly, I repeatedly endea- 
voured to place it out of the magnetic meridian ; but every 
Vol. LXXVI, X endeavour 
