G.W. Dean—Longitude Determination across the Continent, 448 
Formule used in the Reductions. 
STAR. 
LampTallies 
a 
O. 
M.U | Mean of Tallies 
F. Mean of Thread Intervals. 
when F sec 0 is less than 2", it may be neglected. 
log R. 
hk R=F sec dog; and is to be added to M te. —— the Time 
of Transit over the mean of all the 8. 
6, =the level correction in time,,c dete ‘oot inequality 
| "of pivots: it is positive for west end high. 
A. A= sin ie 
q 5) { 180 °—d being used instead of J when 
B. B= sete ne star is below the pole. 
cos 
t do. 
C, C= secd 
%. x = the diurnal aberration = sec 0°021 cos g sec J, It is 
(—) in upper and (+) in lower culminations. 
Ba,. 
T. | T=M4+R, 
z. t= ay ah “BB, 
. o=e —t= St Aas 
Ce, 
“9 =w-+ Ce, upper sign for lamp west. 
The co. satan constant (c) is determined from reversals on 
circumpolar stars, and is to be obtained from the equation 
te — ty = Oy — 4, = 20 
A is positive except for stars between the zenith and north pole. 
B at lo ower culmination. 
Cc “ “cc 
The local time and simu are obtained thus: assume an 
the correction for aniee ear bY mls — 
° x daily rate, 
(1) = +* 24 rar 
and we have, putting A= Aat—4, 
rad + shes zw, 
ZAA0-4+ZA2a = SAo’,, 
Haag we determine a, 46, and thence At for the time ne 
