Dr. ingen housz’s Method 
544 
would be fufceptible of a ftrong polarity, fo as to ferve 
for the purpofe here intended. 
But as the two agate caps, if fixed in the middle of 
the fubftance of the tube, would interrupt fome part of 
the continuation of the Heel, and thus leflen the mag- 
netic power, the points of fufpenfion would be better 
foldered or fixed upon the furface of the tube itfelf, and 
the agate caps fixed upon the fupport underneath and 
above the tube; fo that fuch a needle fhould be the re- 
verfe (in refpedt to the fufpenfion) of the common nee- 
dles, Another advantage would be derived from fixing 
the points of fufpenfion upon the needle itfelf, viz. that 
by the motion of the fluid in which it fwims, it would be 
lefs apt to acquire a too ftrong waving or undulating 
motion. 
If it fhould be found difficult to make very thin fteel 
tubes properly hardened, a piece of fteel could be fcooped 
out fo as to conftitute the half of a tube; the other half 
could be made of another fimilar piece, or perhaps bet- 
ter of thin brafs, or any other metal, and they might be 
foldered togther. 
It would, perhaps, anfwer the fame purpofe if a fteel 
magnet was fhut up in a thin tube of glafs or fome 
metal. 
I fhould 
