AMERICAN ASSOCIATION FOB THE ADVANCEMENT OF SCIENCE. 65 



Much trouble was experienced in securing a good casting for the steel axis of 

 the instrument. Three were found imperfect under the lathe, and the fourth was 

 chosen, but even then, the pivots were made in separate pieces, which were set in 

 very deeply, and welded. 



Dr. Gould said he would have preferred a smaller instrument, in which the 

 facilities of manipulation would have been greater, but was hampered by one pro- 

 viso, upon which the Trustees of the institution insisted — that this should be the 

 biggest instrument of its kind, and the instruction was obeyed. He had been l'e- 

 quested by the gentlemen who had this enterprise in charge, to suggest, as a 

 mark of respect to a gentleman of Albany, who was a munificent patron, 

 of Science, that this instrument be known as the Olcott Meridian Circle. 

 The other large instrument for the Observatory, the Heliometer, has been 

 entrusted to an American artist, but is not yet completed. It was also announced 

 that the American Astronomical Journal, hitherto supported at Dr. Gould's own 

 expense, was in future to be published at Albany, under Dr. Gould's editorship, 

 the responsibility of its cost having been assumed by a number of gentlemen of 

 that City. 



Among the Astronomical papers read before the Association was one by Dr. 

 Peters on a Periodical Comet of thirteen years. This Comet was discovered by 

 Dr. Peters, at Naples, in 1846. He has prepared an ephemeris of the Comet 

 from 1857 to 1860. The comet was very difficult to observe; its light was so 

 faint in 1846 that he could not perceive it until he had reposed his eye for some 

 seconds in darkness. Even under these circumstances he had only seen it at inter, 

 vals during a period of twenty days. He had devoted some time to calculating 

 where the comet might be looked for on its re-appearance, and had drawn lines on 

 a map, from eight days to eight days, so that the observer would be saved much 

 of the labor of sweeping, and the comet could readily be discovered. The proba- 

 ble orbit gives an ellipse of thirteen years, wilh a probable error of one year, so 

 that its period might be twelve or fourteen years. In 1854, Saturn came into 

 nearly the same position as this comet, and some uncertainty exists as to its dis- 

 tance, it having been difficult to ascertain whether it was nearer the interior or 

 the exterior of that planet. Unless some accident had happened, the comet might 

 be looked for either fifty-six days before or fifty-six days after the 15th of March, 

 1859. This enquiry had become of more importance since two comets pronounced 

 periodic, those of de Vico and Briinnow, had failed to re-appear. Dr. Peters re- 

 marked that the discovery of comets has decreased. Last year, not more than one 

 or two were discovered. He thought this falling-off is owing partly to the fact 

 that the award of a comet medal has been abandoned by the King of Denmark. 

 For many years, the discoverer of any telescopic comet received a comet-medal 

 from the King, but in 1848 the custom was abolished, and the zeal for discovery 

 has since declined. He hoped the institution of the comet-medal would be re- 

 newed here. 



Dr. Gould observed that it was not a little curious that since the establishment 

 of the Observatory at Pultowa the realm of Denmark had contributed 200 per 

 cent, more to the progress of astronomical science, in proportion to its population, 

 than any other country. The comet medal, whose institution was suggested by 

 Schumacher, continued to be awarded for fifteen years, during which period the 

 discoveries of comet3 averaged five to seven per annum, and the average discover* 

 VOL. H.— K 



