5 42 Dr. ingen housz’s Method 
could be fupported on either of the caps, and turned 
with either furface upwards. I fixed on one of the flat 
furfaces, on each, fide of the center, a thin glafs tube, 
hermetically fealed, of fuch a fize, as made the whole 
together dip in the water fo deep that only a fmall 
part of the glafs tubes remained above the furface of the 
water. I then deprefied the needle entirely under the 
furface of the water by thrufting a metallic point in the 
cap which was uppermoft, and fixing this point to the 
cover of the bafon : thus the needle, kept under water, 
bore againft the point only with that fmall degree 
of prefliire which the very inconfiderable difference of 
fpecific gravity, which it had above an equal bulk of the 
water, could give it, which did not amount to above a few 
- grains of weight. Thus this needle, lofing nothing of 
its polarity, loft very near the whole of the refiftance of 
its weight, and at the fame time that quivering motion 
and reftleflhefs, which it had in the air, moving fmoothly 
in a medium, which could only obftrudt its too great vi- 
brations (almoft in the fame way as aftronomers flop the 
vibrations of their plumb line by hanging the weight in 
water or oil) without obftrudting (but retarding only) its 
tendency to the magnetic meridian, liquids prefling 
equally on all fides. 
To 
