On Shooting Stars. 99 
Let A be one, and B the other place of observation upon the 
earth, whose center is C, pole P, equator NQM, and X the observ- 
ed point. From A,B,X drop perpendiculars to the plane of the 
equator, meeting itin a,b,c. Put A’=the Right Ascension of mid- 
heaven for B, B’ its geographical latitude, R’ its distance from the. 
center of the earth; and let A’, B”, R” represent the same for the © 
point A, then is Co=R’ cos. B’, Ca=R” cos. B”, and aCb=A” — 
A’. Call the Right Ascension of the meteor as seen from B=’, 
its Declination=0’, and let a’’, b’ represent the same for the point A, 
then is wbL=a’ — A’, caK=a’’—A”; and if & represent the 
Right Ascension of midheaven for the point U where the meteor 
stood in the zenith, thenis tCa=x —- A”, cCb=x—A’. Wethen 
Cob. sine bL Ca. sin. raK 
Jae Cos Visi Czb, Mpa xa ae 
R’ cos. B’. sin. (a’— A’) R” cos. B”. sin. (a”—A”) 
Ct mre ry a Ta Ge a ean 
sin. (a/— <2) sin. (a’’ — x) 
whence we easily obtain 
R’cos. B’sin. (a’ — A’)sin. a” —Rcos. BYsin. (a’”— A”)sin.a! 
tang 7=R7cos. B’sin. (a’—A’)cos. a” —R”cos. B’sin.(a” — A”)cos.a’ 
Hence x — A’, the difference of longitude between the place of ob- 
servation B, and the place where the meteor stood in the zenith, is 
given. 
