VOL. XXXIV,] PHILOSOPHICAL TRANSACTIONS. }43 



again in the same telescope; so that in IS"* 22*^ IQ™ 35^ there were nine emer- 

 sions; and the interval between each was about 1"* J 8*' 28"" 50^ This subtracted 

 from the time of the emersion observed at Wansted, Aug. 27, will give the 

 true emersion at Wansted on Aug. 25, 14*^ 28'" 50' mean time, that is, 4^ 56"' 

 30* later than it was observed at New York. 



Sept. 10, 8^ 0"^ 10' by the clock, another emersion was observed at New 

 York. From the altitudes of the sun's limb taken the morning before, Mr. P, 

 computed the error of the clock at the time of the emersion to be I"' 10% and 

 that the emersion happened at 7*' 59"^ apparent time, that is, 7*^ 5 J"" 52'' mean 

 time at New York. But subtracting the forementioned interval of 1'' 18^28'" 

 50' from the time of the emersion observed at Wansted Sept. 12, 7^ 17"' 13' 

 mean time, we shall have the time of the true emersion at Wansted on Sept. 

 10, at 12*' 48"" 25' mean time, which is 4*' SS"* 33' later than it was observed 

 at New York. The difference therefore of meridians between Wansted and 

 New York, allowing about 15' for the difference of telescopes, is about 4^ sO"" 

 45', and between London and New York, 4"^ 56^"^. So that the true longitude 

 of New York from London is 74° 4' west. 



Eclipses of Jupiter s^rst Sate/lite, observed at Lisbon in the Years ] 725 and 

 1726. By Fa. Carbone. N° 394, p. 90. From the Latin. 



True time. 



1725. July 28'' 12'' 12" 26'. . the satellite immerged into the true shadow. 

 Sept. 12 15 O 10 . it emerged out of the true shadow. 



14 9 28 7 • • it began to emerge out of the shadow. 

 21 11 24 55 . . began to emerge out of the true shadow. 



Oct. 23 8 11 10. . the beginning of the emersion. 



Nov. 8 6 30 4 . . the beginning of the emersion. 



15 8 24 50 . . the beginning of ditto. 

 Dec. 8 8 33 30 .. ditto. 



1726. Jan. 9 4 58 50 . .emersion. 



Iti 6 51 10 .. emersion. 



On the Latitude of Lisbon. By Fa. Carbone. N° 394, p. 92. 



From a number of the sun's altitudes, accurately observed at the Jesuit's 

 college at Lisbon, accompanied with proper allowances and calculations. Fa- 

 ther Carbone determines that its latitude, from a medium of the whole, is 

 38° 42' 30". ■ ) 



