[ 6 °9 ] 
number. But if you have an inclination to undertake 
a labour of this kind, you may meet in the memoires 
of the accademy with occultations of ftars obferved 
at different times, and find fome correfponding ones 
made at London, from whence you may deduce the 
difference of the meridians of thefe two cities, which 
we may be afhamed to fay we are uncertain of to 20". 
For whether it be 9' 15" or 9' 40" is difficult to 
determine : I mean of Paris and Greenwich. 
I am, 
Yours, &c. 
* De la Lande. 
Obfervations of the ijl Satellite of Jupiter. 
1761. h ' " 
July 22. Ini. 12 45 30 Some clouds. Gregorian telef. of 2 \ ft. 
July 29. Im. 14 39 13 Great telef. of 5 feet of Mr. Short’s. 
Aug. 14. Im. 12 56 21 Newtonian telefcope of 4 i feet. 
Aug. 21. Im. 14 52 20 Gregorian telefcope of 24 feet. 
Aug. 23. Im. 9 21 8 Thro’ vapours. Greg, telef. of 2 4 feet. 
Sept. 8. Im. 7 42 7 Gregor, tel. 2 ? feet. 
Sept. 15. Im. 9 39 48 Gregjor. tel. 24 feet. 
Sept. 24. Em. 8 17 26 Gregor, tel. 2 4 feet. 
Sept. 29. Em. 15 45 1 8 Some vapours. Gregor, tel. 2 4 feet. 
Oct. 1. Em. io 14 9 Gregor, tel. 2 4 feet. 
Oct. 17. Em. 8 3,6 25 Gregor, tel. 24 feet. 
0 &. 31. Em. 12 28 7 Gregor, tel. 2! feet. 
Nov. 9. Em. 8 52 12 Gregor, tel. 2 4 feet. 
Nov. i6< Em. 10 47 22 Tel. of 25 ft. refra&or. a little doubtfu. 
Nov. 18. Em. 5 15 30 Thro’ vapours. Gregor, tel. 2 4 feet. 
Dec. 6. Em. 7 16 o Thro’ clouds. Gregor, tel. 2 4 feet. 
