255 . 
XXXIX. 
On the Eclipse of the Sun of Sept.17, 1811, with the longitudes of seve- 
ea laces in this country, deduced prom all the observations of the 
ene Ad the Sun and Transits of Mercu ial Venus, that have 
published in the Transactions of .the al Societies of Pa- 
ris 71 London, the Philosophical Society foe 4 at Philadelphia, and 
the American Academy of Arts and Sciences. 
BY NATHANIEL BOWDITCH, a.a.s. 
And member “ae the Amer. Philosophical Society held at Philadeibhia. 
Bi 
I OBSERVED the eclipse of Sept. 17, 1811, in the garden ad- 
joining my house in Salem, about 300 feet SS W from the meet- 
ing house where the Rev. Doctor Barnard officiates. An excellent 
chronometer, made by Grimalde, was used in this observation. The 
regulation was made by equal altitudes of the sun, observed in the 
morning and evening, for several days before and after the eclipse, by 
an accurate sextant made by Ramsden, and a level surface formed by 
a bowl of Barbadoes tar. ‘The observation of Sept. 16, 17, and 18, 
gave the following result. : re 
App. a by om slow for 
chronometer. pp. time. Diff. 
_ 16, by 28 observations 10h. 47' 520 1h. 12" 087-0 
3 17, “48 10 i47. 22°90.) od AS B74 . 29% 
te, * 36° * 10 46 52°5 1 io 4%... 00.8 
- During the whole eclipse the weather was very clear, not a cloud 
was to be seen, and there was but little wind. The telescope used 
was a four feet achromatic, with a power of about 30. An assistant 
seated near the telescope counted the seconds from the chronometer, 
at the times of the beginning and end of the eclipse. About two 
minutes before the commencement of ae eclipse, the part of the sun’ 8 
