_Longit._ _Latit._ 1757. ° ´ ° ´ Sept. 16. at 4 h. ante mer. The comet in ♋ 10 15 with 10 10 North. 17 -- 3 -- -- -- -- -- ♋ 14 7 ---- 9 38 18 -- 3¾ -- -- -- -- -- ♋ 18 10 ---- 8 57 19 -- 4 -- -- -- -- -- ♋ 22 1 ---- 8 17 22 -- 2¾ -- -- -- -- -- ♌ 3 46 ---- 6 15 23 -- 4 -- -- -- -- -- ♌ 7 36 ---- 5 24 25 -- 4¼ -- -- -- -- -- ♌ 14 50 ---- 4 6 28 -- 4 -- -- -- -- -- ♌ 24 22 ---- 1 41 Oct. 1 -- 4¾ -- -- -- -- -- ♍ 2 46 ---- 0 12 South. 4 -- 4½ -- -- -- -- -- ♍ 9 45 ---- 1 30 9 -- 4½ -- -- -- -- -- ♍ 20 20 ---- 2 40 11 -- 5 -- -- -- -- -- ♍ 24 46 ---- 3 9 But the two last observations will, in my opinion, differ the most; because, when I made them, I was in some doubt about the adjustment of my instruments; and the comet was then far advanced into the morning rays. I have, since the month of February last to the end of May, made sundry observations on fixed stars, with a telescope of 16 inches, made by Mr. Short; and with a pendulum clock, made after the manner of Mr. Graham, by Mr. Vryhthoff of this place. In the months of February and March, by a medium of eight observations, I found, that by the clock, the star Rigel, in every daily revolution, passed 4 min. 2⁴⁄₉ seconds of time earlier, in the telescope; and in the latter end of May I found, by six observations, (the clock not in the least changed or altered) on the star Spica Virginis, that that star, in every revolution, passed 4 min. 5¹⁄₂₀ sec. earlier, in the same telescope; which intervals differ pretty nearly 2⅗ seconds of time from one another. Whether this difference arises from any defect in the clock, or whether it proceeds from any small difference of velocity of the earth’s motion round its axis, I would have been very glad to have endeavoured to find out by farther inquiry, had not the death of Mr. S. Koenig intervened, and I thereby hindered from continuing my observations. The above observations were taken in the observatory of his illustrious Highness the minor Prince of Orange and Nassau, _&c. &c._ under the direction, and with the approbation of the aforesaid Mr. Koenig. After the death of that gentleman, I petitioned her Royal Highness the Princess Governess of these Provinces, _&c._ that I might have leave to continue my astronomical observations; but as yet I have not been able to obtain her Royal Highness’s permission: otherwise I would have observed this last comet with more exactness. Had I been able to pursue the above-mentioned observations, I would, for the greater certainty in regard to the pendulum, have made use of a farther precaution. By means of a stove, with the help of a thermometer, I