140 



THE SAYKE OBSEKVATORY. 



Let 20".4451 + y be the true value of the constant of aberration, x + 8x the corre- 

 sponding correction, 

 Then /c + Ak = (20".4451 -]- ?y)[— JC' -I- "i') oosucos©— J(«?'H <V)sln©]. 



By division 



k 20". 4451 



k + A k - 20".44G1 + y 



From which Ax=x.x where x is written for w , I' ■. 



20.4451 



Let <£>], ^) 2 , <£> ;! , $, be the values of the latitude given by Groups I, IT, I IT, TV, 

 A,, A., A ;1 , At the constant part of the correction which these values require, 

 The true value of the latitude will be 



f = </'l + A l + ",X 



<l'x\- \ -I' V 



</'s + A 8 + V 



= 'h I- Vl" V 



Employing the values of <£>,, <£ 2 , $8 and $< determined on the same dates and sub- 

 tracting the consecutive equations we have 



= </>, — 2 + (A, — A 2 ) -I- (a, — Kl )x 



— <h ~ 'h ' I ( A 2 ~~ A .'|) - I - ("j — "»)« 

 = 'Z 1 !! " 'h + ( A 3 — A 4> "I" 0.1 — "4) 3; 

 = <Pt ~ 'h + ( A 4 — A l) + ('<4 — «'l)»- 



latitude were employed where 



ic same or consecutive dates. 



Adding we find =: 2A<?> + XAx.x. 



For deriving the value of y, those determinations of 

 both evening and morning observations were obtained on I 

 In three eases two days intervened between the morning and evening observations, and in 

 one case three days. 



The details are shown in the table which follows. £<£ is the sum of the seconds of 

 observed latitude for the dale indicated, the foregoing corrections having been applied for 

 reduction to mean declination of group; Sx, is the sum of corrections for aberration. 



The process of assembling in groups and formation of equations seems to call for no 

 farther explanation. 



