Astrono7ny 589 



researches on the orbit of Biela's comet for its six recorded 

 appearances from 1772 to 1852, and asking for the aid 

 of the Institution in calculating the perturbations over the 

 whole interval from 1772 to 1865 (the next appearance), 

 so as to unite, in a single theory, all the observed places 

 of the comet. 



Professor Henry's printed note on this letter highly com- 

 mends the project of Professor Hubbard, but indicates that 

 the assistance desired could not be given at that time. Some 

 assistance was, I believe, subsequently given. At any rate, 

 astronomers have fully appreciated Hubbard's work on this 

 comet, which was printed in the early volumes of the Astro- 

 nomical Journal. 



The Report for 1874 contains a notice of a work of the 

 same sort on the periodic comet of Tuttle (period 13.7 years), 

 which was done by Professor Ormond Stone and assistants 

 at the cost of the Smithsonian Institution. A careful compu- 

 tation of the perturbations from 1871 to 1885 served as the 

 basis for an ephemeris of the comet during its appearance 

 in 1885 (published in Circular No. i of the McCormick 

 Observatory), and the orbit is now in charge of Doctor 

 Rahts, of the Observatory of Konigsberg. 



ORBIT AND PHENOMENA OF A METEORIC FIRE-BALL 



The "Contributions to Knowledge" contain a paper ^ by 

 Professor James H. Coffin with the title given above. This 

 great fire-ball was visible about 10 r. m. from Lake Mich- 

 igan to a point at sea southeast of the island of Nan- 

 tucket, — a distance of 1300 miles. The observed path of the 

 meteor was its orbit with respect to the earth as a center of 



l"Tlie Orbit and Phenomena of a Meteoric Fire-Bali seen July 20. i860," in Volume 

 XVI of the "Smithsonian Contributions to Knowledge, 1869.'" 



