1840.] Fort William, and Futtehghur. 77 



which Mr. Taylor thinks may be 8 or 10 seconds in defect. Mr. 

 Taylor, who has now,, I believe, gone to England, will no doubt 

 find there, numerous observations with which he can compare 

 the above, and the subsequent observations he has made, and 

 will be able to put to the test, the value of the lunar transits, 

 when he has the comparisons from the 1st. and 2nd limbs 

 of the moon in equal and greater numbers; he will also get 

 correspondents for his numerous sights of Jupiter* s satellites : 

 we shall then see, how far the two modes, by the transits 

 and by the satellites, agree with each other. It is an inquiry of 

 interest, but in the interval, I think we may fairly take the 

 mean of what I have above stated, thus- — 



h. m. s. 

 Mr. Goldinghanr's 1st. and 2nd satellites, 5 21 9*40 

 Mr. Taylor's 1st. satellite and lunar transits 3*77 



Ditto, 2nd. satellite of ditto, ditto, 5 20 55*62 



Mean Madras Obsij. 5 21 02*93 



The following series of nine immersions, and eight emersions of 

 the first satellite is selected from my notes, as having been made 

 under the circumstances most favourable to accuracy. Those 

 circumstances are, that the immersions and emersions be equal 

 in number ; these are nearly so— -it is proper that they should be 

 taken with telescopes of the same description, at either place; 

 these were so taken, the telescopes being those of Dollond, of 

 45 inches focal length, aperture 2 inches *7 and power 70 to 75 ; — 

 that the same person observe at each place ; I myself did so at 

 the Surveyor-Genera? s House at Chowringhee, Calcutta ; and the 

 same individual, I believed, took the eclipses at the Madras 

 Observatory — the satellite was the first, which by reason of its 

 quicker motion, gives the best results. The circumstances of 

 climate, and altitude of the planet, did not very materially differ 

 at Calcutta and Madras. When these conditions are attended to, 

 a moderate number of corresponding sights will give a better 

 difference than a far greater number would under other cir- 

 cumstances. I have the dates and particulars of all these 

 eclipses, but it would take too much space to insert them here ; 

 they were taken in 1821, 1826, 1827- The differences in time, 

 reduced to the Flag- Staff, are — 



