moveable fight (fcj either a Thread nearer or a Thread farther of
frortf the fficB hghtrf^vthe •(*&> ^hich.will,not adrfiit-of any
fhaking'T There are Sixty of thefe Threads, andanfwerable
thereto are made‘Sôftÿ divMiöfi^ on the. dbg® <?f tlid Möïi ör
• RulerblS'Jléand'a Iroall Index ■ ($ fix d;to theBohc» faaa) defifotes
Jiiow. many Threads the edges oTtkeltwo fights;#^ ; and d(!if)îare
diftant ; Éd the îndex fiê) (hews on the circular platejwvhat
part ofa Revolution there is more,; every Revolntidnasrwas faid
before being divided into an hundred parts, at the fame :time^that
the; movable fight (h) is moved forwards or backwards* or -more
Threads of the courfer Screw, is the plate": (pp in Fijg. ie^ fo as
the middle, betwixt: i the .fights may lie in the Axis'rof dhfeQlafs,
however the .Screw be turned, The midft betwixt the .fights, will
.always be in;xthe Axis, and the fights will equally^either open
from ity or (hut towards it.
..Figures.1 Reprefents the mcweâblêcover^tainingjtheScfews,
to be by the Bookfeller cut
Paper, and;to be fitly p l a c e d ' o n ' aCcördfe^’tó' the
pricked line ’(yjp} dnfwering fherCtOj ttecby the taking- off1MtiÊk
were, or folding up of thiscove-r^; the inwardContrivanCdof the
Screws, and fights may appear.
And becaufe ft isxofaeeivbl by fome Ingenious Men^: that it
will be more convenient ittfteâd ôf the edges- o f the1 ïWfcf fights
(b.&rjto employ two fights, -fitted with hkirs," theref^éis add*-
ed Figure fa.) Reprefenting the two fights,1^ si)fo fitted with
Threads, (t t/y u) that they éiayi be cofrveniently^ufed dn the
place of the iolid edges of thé fights (h i/y t i) :
The fourth Figure reprefents,: how the Screws are to be put on.
The Table (A D, ) is divided into three lengths, of which (as
in ordinary onesT (A. C.) is to, lengthen or Contrabt, .as the ob*
je& requires; ButA. JBa. is here added,; that at A. yon may put
fuch Eye. piaffes,. as lhall be thought moft convenient and to
fet. themftill -at the diftance moft proper for them, Indexes, or
Pointers, ’which here are fuppofed to be at, B. which length
alfo alters alfo in. refpeétof divers Perfons £yes,<(£.) is aScrew,
by which the great Table can be fix’d fo, as by the help of the
Figures
Figures any ftnafe-rpart !of. it Cap iminediaite^fcje-Found,; meaJ-
«furing’Qnly or knowing^ Divifions pud (rSr,G ) . the diftanoë óf
thehbje® Glaffe-s ffom the Pointers if^fi#rhe;-Anpfcfcfcpieéq óf
Wöpdthat liesontheupperScrew^ffth^re^kMsrbftdsfêprefeb^-
ed, by Figure the’5 th. Asïfór; a deforiptiofi-dfthe mfes of this ingé-
niouftyvcontrivedv^arid veryiehrious ^ngirfêi,; iied&aberma^Uri'
derftand it by the precedingiTetter. (i
To this may 'be.aunexed:anóther lbgtiér b{ fagéftibds
Gentleman,
fallings' Monthly? fe; f e v e r i a l i I a f % i -
ldws.
I j ... « J a n .f t f t i 6 ^ \
“T fHave now. completed t e l a f t $ ëtó?l ©bfeva&êfëf Which t
JL I f was Wëry defiïöus ftlöü%. accbmpahy tië bffiëfs ThuW'fèh^
“ you, and I hope you will bê*'plèaféS èpë# thWfëëfëdo1 j^rdbn
‘c my delay in ’obeying your Commands * I wi(h ttè yT a dÖ n
“ more exa&lymifde, and fhou’d have ;bëèn:fójjfi had they bebni
41 intended for shy.’thing bfit my ovvn fa'fisfaaiö'^^^nd éiïkWhg
k me to give fome Conjecture at the Prop'ortion of -Rain thnfe^ fk^Lls
a in this Country,-: with'that&tTon^^-arid in Öêherpa'fts ofthis
“f'Ribgdojn, Mb in this I ha-vEnot yltv^ïki^êm^my dêfitfédérid^
‘i not havihg-heard of the like trade fii. ü y paft' ^EHghn^^Èió1
“ a Ftiend or two^Had proffiifed to
‘>ri|lCcount of their ©bfe^Vëtóöb^, 1 bWit nfeycM ShCy^^lid3*®)!'
% think it worth their :whiië^ï!öf that' it^ éü ’d pr0vë!®5t#Ff^i-'>
‘‘ blefome thandTóühd |N For-f only him^a rèünd’TötmêFöf ^T 2
inches Diameter to a lêadeö'-Pipé^hwltièh could -admit o f ho
“ Water bht whaü came through thé Tónnel,
vTodèr’d to I thdTunnel-il felfi Which-Wént qveEfhe^Pipe]1 ahd
4‘ fetved alfo to fix it to it, as well as to keep diif any ;Wet, 'thkt
f in ftormy Weather might, béat- againfithe under '^trEdf 'the
“ Tunnel, whi'ch was fo placed thaf there Was mo biiildihg rtrar"
Ifi it, that; w:ou’d give 'öCCSfióif to füfpécl, * that it did hot féfeëiie
“ its due Proportion of Rain; that, fell through the Pipe forne
F “ nine