[ *+] 
Received November i 6 , 1767. 
IV. An EJJay o?i the Connexion between the 
Parallaxes of the Sun and RIooji ; their 
JDenfeties ; a?id their dijlurbing Forces on 
the Ocean . By Patrick Murdoch, D . D. 
F. R. S. 
Read Feb. 18,^ N a letter to Mr. Reid, formerly pre- 
i fented to the Hon. Society, and printed 
in Vol. LIV. Part II. of the Tranfactions, mention 
was made of a rule which I had ufed for computing 
the fun’s parallax j but as that rule, though it gave a 
folution near the truth, was in part founded on au- 
thority (which, however refpe&able, ought to be 
cautioufly admitted in fuch enquiries), I have conii- 
dered the iubjedt anew, upon fuch principles alone, as 
the eftablifhed theory and the heft obfervations fur- 
nifhed me. And the refult is now humbly fubmitted 
to the Society. 
I. The length of a fecond-pendulum at the equa- 
tor, and on a level with the fea, being 36 inches 
7 lines, Paris meafure, according to the accurate 
obfervations of M. de la Condamine *, that length 
* Journal du Voyage, &c. p. 163. In the copy of this paper, 
which was read in the Society, the length of a fecond-pendulum, 
at the equator, had been computed from its length at London : 
but here it is taken from the immediate obfervations of a very 
able allronomer. Some other Imall alterations have been made ; 
and the examples placed in a better order. 
(properly 
