Mijcellanea Curiofa. a6i 



SP, and $ i to BL, and the Arch S T, to the 

 Arch LS, being the femidiurnal Arch in that La- 

 titude and Declination ; the Sine whereof, tho 3 

 not expreflible in Fig. 4. mull be conceived as 

 Analogous to the Line TS or UP in Fig. 3. 



The Relation between thefe two Figures be- 

 ing well underftood, it will follow from what 

 precedes, That, the fum of the Sines of the Meri- 

 dian Altitudes of the Sun in the two Tropicus? (and 

 the lil^e for any two oppcjlte Parallels) being multi- 

 plied by the Sine of the femidiurnal Arch, mil 

 give an Area Analogous to the Curve Surface 

 ^{MSQJ>Py and thereto adding in Summer, or* 

 fubftratling in Winter, the Prcduft of the length of 

 the femidiurnal Arch, ( taken according je^Y&n 

 Ceulen'j Numbers) into the difference of the above 

 fa id Sines of the Meridian Altitude : The fum in 

 one cafe, and difference in another, fhall be as the 

 Aggregate of all jhe Sines of the Suns Altitude % 

 during his appearance above the Horizon j and con- 

 [equenfly of all his Heat and Atlion on the Plain of 

 the Horizon in the propofed Day. And this may 

 alfo be extended to the parts of the fame Day ; 

 for if the aforefaid Sum of the Sines of the Meri- 

 dian Altitudes, be multiplied by half the Sum of 

 the Sines of the Sun's Horary diftance from 

 Noon, when the Times are before and af- 

 ter Noon j or by half their difference, when 

 both are on the fame fide of the Meridian ; and 

 thereto in Summer, or therefrom in Winter , 

 be added or fubftra&ed the Product of half the 

 Arch anrwerable to the propofed interval of Time, 

 into the difference of the Sine s of Meridian Alti- 

 tudes, the Sum in one cafe and Difference in the 

 other, (hall be proportional to all the Action of 

 the Sun during that Ipace of time. 



S $ I fore- 



