C540 
fim other impedmem intervened, ( after it was come to hand,) 
Firfi on the Pubiilher's, then on the Engraver's ftde^ the follow- 
ing Particulars concerning the fame, promifed fome Monet hs ago, 
had he en imparted to the Fuhlick agood while before this time. 
F^r the draught of the Figures, reprefenting the New Inftrument 
it f elf and the Defcription of the fame^ we are obliged to the in- 
genuity of Mr, Hook. 
THe I. 2 and 3 P/j-z^Wj do reprefent the feveral parts of this 
Inftrument the 4^^ Figure^ part of the T elefcope with the 
Inftrument applied to it> and the the Rej} 5 on which the 
whole repofeth. 
The I. P/^/^r^reprefentsthe Brafs-hxe with the whoklnfiru- 
mnty (excepting onely the Moveable Cover,) and the S crews ^ 
by which it is fixt to the T elefcope^ In this Figure {aaaa) is a 
fmall oblong Brafs-hox^ ferving both to contain the S-crews, znd 
its Sockets oi' Femal Screws^ ^nd alfo to make all the feveral move- 
able parts of the Inftrument to move very true^fmooth, and in 
a fimple dire^l motion. To one end hereof is fcrewed on a Round 
pLre of Brafs ( bhhb) zbont 3 inches overt the extream Limb 
of whofe outfide is divided into a 10 ^ ^^«^/parts, and numbred 
by 10, 20. 30. ^c. Through the middle of this Plate^ and the 
middle of the Box {aa:a) is placed a very curioufly wrought 
Screw oi about the bignefs of a Goofe-quill, and of the length 
of the Bi)x y the head of which is by a fixed Ring or Shoulder^ on 
the Lifide, and a fmall springing Flate^ ( dd) on the Outfide^ fa. 
adapted to thePlate,thacitis not in the leaft fubjed to fhake.The 
other end of this Screw is by another little Screw ("whofe fmall 
point fills the C enter or hole made in the end of the longer Screw^ 
for this purpofe) rendred fo fixt and fteady in the Boxe^thsit 
there appears not the leaft danger of /baking. Upon the Head 
of this Screw without the Springing-Plate^ is put on a fmall Index 
(^ee) and above that a Handle {mm) to turn the Screw xovrndj 
as often as there ftiall be occafion^ without at all endangering the 
difplacing of the Index it being put on.very ftiff upon a Cylin- 
drical part of iht Head^ and the Handle upon a Square. The 
^mw]mh that 7 bird of it^ which is next the Pto^^bigger than the. 
other 
