( 3 »> ) 
1 8 or xo Pounds Weight, when the End of the Ann 
is carried clofe to the fmall Head^, Fig. i. and confe- 
quently (the Semidiameter of the Pillar being an Inch 
and Half, and the Diftance of that Head from the Axis 
about 28 or 29 Inches) the End of the Arm will be car- 
ried by the united Forces of both the Springs, towards 
the other End of the Reft, with a Force equivalent to the 
Weight of about two Pounds. Each of the Pegs, Y and Z, 
turns in a Hole made in a Piece of Wood /, faftned to 
the under Side of the Arm ^ and the Pieces being flit with 
a Saw from one End through the Hole, and about half 
an Inch beyond it, the feparated Parts are drawn to- 
gether by a Skrevv w, till the End of the Peg is griped 
between them, with a due Degree of Force. By thefe 
Pegs, with the help of the Telefcope H, the Tube is 
eafily direfted to any Objed, and made to accompany 
a Celeftial one in its Diurnal Motion, while the End of 
the Arm moves the whole Length of the reft. 
If it be deflred, that when the Objed is found, the 
turning of one Peg fliould carry the Tube along with 
the Motion of the Heavens, fo as to keep the Objed al- 
ways in fight 5 this may eafily be effeded in various 
Manners. 
The concave Surface of the Objed-Metal has many 
little Spots in it, which could not be brought to take 
a Polifh. In one, or two Places, the Metal itfelf 
feems to have fome fmall Parts, fomething harder or 
fofter than the reft, occafioning an irregularity in the 
Figure of the Metal about them. But thefe Parts being 
fmall, in Proportion to the whole, do not feem confi- 
derably to affed the Diftindnefs of the Appearance. 
The open Air has commonly an undulating Motion 
in* its Parts, efpecially in the daytime, which occafions 
the Rays of Light to defied a little from theftrait Lines, 
in which they ought to move, in order to render the 
C c c 2 Species 
