: pa muft be Lived, „When it is fouth. 
MATHEMATICAL (PAP. Ek S. 75 
tions, sete again by the tangent of the geographical lati- 
` "The fécond part confifts of the. faid change in the de- 
ion, multiplied by the tangent of the fun's declination, 
ct, again by the co-tangent of the fun’s horary angle. 
When the -fun’s declination is north, this fecond part of the 
equation is to be fubtratted from the firft ; but when i it isfouth, 
it is to be added to it ; and the difference or^ füm ` will be the 
equation to the equal altitudes : Which equation is additive, 
when the fun is declining fouthward ; i. e. when the declina- 
tion is north decreafing or fouth increafing ; but when zu con-- 
trary, it is fubtractive. - 
Thefe rules are to be obferved, when the latitude i is north: 
e: "ef i'n ila Will appear, byn By 
Whole change in declination 6’ 22^. Half do. 3111” added 
to 5^ 1' o", the declination at the time of the morning obfer- 
vation, gives 5? 4' 11^ for 6's declination at noon. - AG 
Half change of declin. EL ii Egi" 2 2810334 
x Secant of co-hour angle, 40° of o .— IO 1157460 
+x Tangent of the latitude, . 42 23 28 9 9603952 
Firft part of the equation, 227, 6 2 3571746 
4s. 
w 
UR e K2 . Half 
