[ 296 ] % 
Fig. IV. The brafs fcale with its 
under-piece to be {crewed to it, and 
ferving to embrace clofely, by its 
{pring, the glafs tube, fo as to be 
fufpended by it upon the brafs gingle, 
exprefied in Fig, V. The infide of 
this under-piece ought to be lined 
with a piece of fponge, on purpofe 
to prefs foftly againft-the glafs, 
and to prevent its being fcratched 
by fliding the glafs tube up and 
down. againft the brafs, 
Fig. V. The gingle, or the two 
brafs rings, fuch as are ufed in 
_ common fea-compafies, whofe move- 
_ able axes act contrary to one ano- 
ther, to give the body fufpended 
upon them every poffible motion, 
| a thus to keep it in a perpendi-_ 
N. B, 
