La Valette hy Astrmomkal Observations. ^81 
Solar Eclipse, May 5. 1818. 
I observed the beginning at 18^ 12“ 2T.5, the end at 20*^ 29”* 
ir.5, mean time. May 4th, at La Valette, with an achromatic 
telescope by Gilbert, of 44 inches focal length, and 2.8 inches 
aperture. The observation was made in Strada St Paolo, 
nearly under the meridian of the palace, but about 120 fathoms 
to the north of it. I have used the latitude 85° 54' 0".8; and 
the longitude is supposed to be 14° 30' 30" east. 
The Baron de Zach observed the end at 20^ 15“ 28®. T, mean 
time at Genoa, St Bartollommeo degli Armeni, Pallazzo di 
Durazzo, in latitude 44° 24' 34", and longitude 8° 55' 37" E., 
well ascertained. 
I have reduced the latitudes to the Earth‘’s centre, and com- 
puted its radius by the 3 ratios 
320 299 329 
321’ 300’ 330 
5 and used a mean. 
Place of Observation. 
Reduced Latitude. 
Log. Radius of Earth. 
La Valette, 
Genoa, 
35 43 49 
44 13 12 
9.9995309 
9.9993285 
Let <p be the reduced Latitude, B ([ ’s true Latitude. 
Obliquity of Ecliptic. ^ augmented Semidiam. 
b Zenith distance of Nonages. ^ , (^’s apparent Latitude. 
L d’s true Longitude. P — ^Diff. of Equat. Parallax. 
D d’s equat. hor. Seraidiam. ^ Diff. of Parallax in Long. 
0 Sun’s mean Longitude. 
d Sun’s Semidiameter. 
g Radius of the Earth. 
Arcli of Meridian. 
A Longitude of Nonages 
Then cos cos (p = cos M 
b 
Sin M sin (n+«) =sin. 
g \ eos L-.)=cosA cos Atan (L-x) ^tan.^ 
^ COS B ^ 2 sin ^ I A 
Sin ^ cotang (p = cotang N 
Tan M cos^N4-A»^=tanA 
g sin (P — p) sin 5=sin C Cos ^ X 
cos|(B— +_C)sinJ(B qlC). 
cos B sin ^ i A 
i D X cos cos 
cos B sin A ”” 
N, M, and A are auxiliary Arcs. 
:tan/S 
