of fufpending Magnetical Needles. 543 
To prevent this needle from being fhook off the point, 
and wandering about in the bafon, 1 placed alfo a metal- 
lic point underneath, upon which the under cap muft 
bear if the needle fhould by any caufe defcend from the 
upper point, or if I Ihould chufe to make the whole link 
by increafing its weight. 
Having now found, by experience, that a faxing mag- 
netical needle did point to the magnetical meridian near 
as well under water as in the open air, and that by the 
refiftance of the medium much of its too great verfatility 
was taken away ; I wanted to try, what degree of mag- 
netifm could be given to a thin fteel cylindrical tube, as 
a needle made in this lhape could be as light as required 
without being incumbered with cork or glafs tubes ; but 
finding no fuch tubes ready made, I tried one made 
of tin and found it fufceptible of a much greater 
magnetic virtue than I expeiled, confidering that 
the iron plates of which it is made are neither fuffi- 
ciently hardened for this purpofe, nor approach 
enough to the nature of Heel; befides that, being co- 
vered with a pewter coating, they cannot be expofed to 
the bare friction of a fteel magnet. 
This experiment, however, afforded me a certain 
proof, that a magnetic needle, made of a thin fteel tube, 
4 B 2 would 
