[ 1 57 ] 
fuppofing that you Gentlemen have received it. The 
latitude of Selenginfk is 5 i d 6 / 6 // . I have fettled the 
longitude to be 50 " from the Paris meridian. 
Some immerfions of the firft and fecond fatellite of 
Jupiter have given me 6 h 57'i5 // , 6 h 57 / 2o' / , and 
6 h 58 / 3 1", by comparing the obfervations of Mr. 
Rumowfki with the tables corrected upon the obfer- 
vations made at Paris and at the Cape, and eftimat- 
ing, as well as I was able, the different effects of the 
reflectors and telefcopes. The 15th of July, Mr. 
Le Monnier obferved the meridional tranfit of <p Sa- 
gittarii at 1 8 h 25'3 8 /7 \ of his clock, being at 
76 °oo / 45 // from the zenith. The preceding limb' 
of the Moon paffedat 1 8 K 3 8 / 2 8 /7 4, or at nhoi^o" 
apparent time; when the center paffed, the diffance 
of the upper limb was at 75 d 52 / oo // from the zenith; 
and the lower at 76 d 22 / 25 // ; the threads, which are 
5" thick, beingentirely upon theMoon. cr Sagittarii had 
paffed at i8 h 35 / 22 // 4-> the diftance from the zenith 
being 75 d 22 / 20 // . I have obferved at Rodriguez the 
immerfion of cr Sagittarii at 14^0 \.' 2W' 1- apparent 
time, and Mr. Rumowfki obferved at Selenginfk the 
immerfion of <£> at n h 24 / 5i // apparent time. Upon 
comparing all thefe things together, I find the lon- 
gitude of Selenginfk to be 6 h 57'2 i // i. Ea ft from Paris. 
But this goes upon the fuppofition that the error of 
the tables has been quite conffant during near 7 hours, 
which cannot be warranted. Laftly, the obfervation 
of the eclipfe of the Sun made at Selenginfk June 3, 
1761, compared with the fame obfervation made at 
Toboifkand at Cajanebourg, determines the longitude 
of Selenginfk 5 h i6 / 4i // -L Eaff from Cajanebourg, and 
at 2 h 3 4' 3 o ' ' Eaff from T obolfk ; confequently 6 h 5 8 X 2 2 / 
Eaff, 
