Astronomy,

^ddl ^ 6 ^ ea ** on we ca ^ t ^ ic Spring j the3 b e ^ e °f which is shewn by the Index to^de^J 1 th of March , as this Machine was

lS s

f « the OJd-Stile.

As

^Ar Lii „

C 0 m EO — a, and Radius — I; then is x /i —^ x* of the Angle ZNS fwi Sine of the Angler (P er Spherics) we have h c f I — x x ± ,a d-

fluv- Sun’s Altitude S B ; which multiplied by'° n °t Time — z will produce the

tlf , °f the Sun’s Heat, viz. k X b e ‘J i — x~ rb a 3 .’Putti

-XX

PlateLXIVMFig, 6,

‘hepT’^r

Hi

Sun’s Heat, vip-g, V i —

; X b.c V s J

— h, a d—f

’ — r we have

. 7.1 ot the Heat zzzXgb ±-f __ ^ « £

l hS;‘ ^ow to find the Value of *, letA » A’ 0 f efe E C theCo-fine, -m> Krfta C B_ avvn infinitely near to E B, and B . P‘ g qC n * t * S evident from the fimdar h ' l "

i. That EC : BC :: D G : G B, or h . I -

PlateEXIF.Fi S- 7-

*/

He

U3£l on of the Heat, whose Fluent is xg ± fz,

e nce z — — • wherefore — X gb± f~ ::g :h b

1 e gse ref ° re is as the Quantity of Heat from NoonOf**. p r ® n Time, as required. '

h a 111 t his Theorem we may calculate the Heat^ H T ^S ar I* 1 any given Latitude required :

£Ple s

{V

4 ^ich T ‘ U Cne .. _ j o ___-i - j

^Plez, . shall give the several following useful Ex-, t it be required to express the Heat of an

ftUCl' i n * fc .lt-.LjUlI.CU tu CfJ.

wid&C- ti>e Equator . In this Cafe thef^Sue 0 ) ^' ace > s Nothing, therefore « = oj~adz — o. In the other remainingth ?S ^ = ?> f = I ; therefore the Heat wiH '

Wf ^ e at 1 s f nce the Semi-diurnal Arch is 90 Degrees,He TX 0 *he half Day will be as x m j and of the

iti- 1,1 f ■

ji jfttitug e Hat of an Equinoctial Day le required for

■° t) P M: °f rT °

'epi- -c

fnation

51 ° 30'; then because in this Cafe there.

°f the Sun, d zz 0, and so a dz — 0.