238 



PHILOSOPHICAL TRANSACTIONS. 



[anno 1787. 



V 



By Emersions. 



Diff. of me- 

 ridians. 



1773, Nov. 1 



1775, Feb. 15 



Mar. 17 



1778, Mar. 13 

 Apr. 12 



1779, Mar. 30 

 Apr. 1 



1781, May 24 



31 



1782, Aug. 29 



1783, Aug. 2 

 Oct. 26 



1784, Sept. 5 



1785, Nov. .9 



16 



Mean of 15 em. 

 MeanofSimm, 



Mean of both ^ 

 means • J 



DifF. of mer. Circumstances of the observations at 

 corrected. Greenwich. 



gm JQS 



10 44 



9 43 



10 46 



9 46 



10 43 



9 56 



49 

 8 

 27 

 54 

 45 



9 4 



9 26 

 9 45 



9 44.4 

 9 17 



9™ 3' 



10 37 



9 36 



10 46 



9 46 



10 43 



10 9 



9 49 



9 8 



9 27 



S 54 



9 45 



9 9 



9 26 



9 45 



9 42 

 9 19 



9 31 



9 30| 



6 F. air a little hazy. 

 6 F. twilight. 

 6 F. air a little hazy. 

 — Bright moonshine. 

 Air hazy. 



2 F. reflector, air very clear. 

 Air very clear. 



Air very clear. 

 Air very clear. 

 Air very clear, but Jupiter low. 



Air very clear.' 



1 8-inch reflector, new metals, 



Circumstances of the observations at 

 the Royal Observatory at Paris. 



Air very clear. 

 Air very clear. 



Air hazy. 



Air very clear. 



The sat. very near Jnpit. disc. 

 Limb's undulating much. 



{5-feet reflector by DoUond, 

 magnifying 450 times. 



Hazy. 



Before the 24th of May, 1781, a 34-feet achromatic telescope of Dollond, 

 of 42 lines aperture, that was but an indifferent one, was made use of at the 

 Royal Observatory at Paris. From that time a very good one was employed of 

 the same siZie and aperture. 



Difference of meridians of the Royal Observatory of GJreenwich and the Hotel de Clugny at Paris, 

 2' of time east of the Royal Observatory, deduced from observations of eclipses of Jupiter's first 

 satellite observed at both places. 



