[.* 5 ] 
IX. Occultatio Jovis a Luna, obf. LondinL 
Read June 7. 
1744. 
Notante Horologio. 
d h / // 
1744 .June 6 , ii 13 40 Immerlio centri Jovialisfat cerfe. 
35 14 aSerpentaria culminat. 
43 15 Emerfio centri,raptim inter nubes. 
Tubo 12 Ped. 
J. Bevis. 
X. A letter from Mr. Abraham De Moivre, 
F. R. S. to William Jones, Ffquire , F. R. S. 
concerning the eaftefl method for calculating 
the value of annuities upon lives-, from tables 
of obf ervat ions. 
SIR , 
Pre/ented June 7 '%f O U may remember, that fome time 
J 744 - after the printing of the fecond 
edition of my book of annuities on lives, you 
told me, that it feem'd ftrange to you, that, con- 
hdering I had demonftrated the chief proportions in 
the book, 1 had negledled to demonftrate the theo- 
rem, which is found in page 8 < 5 . line 12. which, you 
faid, of all the reft, appear’d to you the moft curi- 
ous j I anfwer’d, that, as the demonftration de- 
pended upon a principle which was not commonly 
I known 
