EEPOKT OF THE SECRETARY. 17 



presenting tlie subject. After these modiflcation.s liatl been made, it 

 was submitted to the American Oriental Society, and was by it referred 

 to a special committee, consisting of Messrs. Hadley, Trumbull, and 

 Whitney, who, having critically examined the memoir, reported that it 

 contained a series of highly interesting facts, which, they believed, the 

 students of philology and ethnology, though they might not accept all 

 the conclusions of the author, would welcome as valuable contributions 

 to science. 



The investigations of Professor Newcomb, relative to a new orbit of 

 the planet Uranus, in continuation of those relative to the planet Xep- 

 tune, an account of which was given in previous reports, have been tem- 

 porarily interrupted by the visit of the author to Europe to observe the 

 total eclipse of last December, and to collect ancient observations for 

 correcting the mean motion of the moon. These investigations were 

 commenced as far back as 1860, but Professor Newcomb had so little 

 time to spare from oflicial duties, and had to depend so much upon him- 

 self on account of the methods to be employed, that four years elapsed 

 before even the first formula} for the i^erturbations were computed. The 

 best accepted elements of the planets were first used, viz, those of 

 Bouvard for Jupiter and Saturn, and those of Pierce and Kowalski for 

 Neptune. The calculated places of Uranus and I^eptune were found 

 from these data to differ so widely from the true ones given by observa- 

 tion as to show that the elements of these planets which had been 

 adopted were not to be relied on. A re-investigation of their orbits 

 therefore became necessary. That of Neptune was made exhaustive. 

 The magnitude of the corrections required in the old elements is shown by 

 the fact that the longitude of the perihelion of Neptune was changed 

 by about four degrees. This investigation was published by the Insti- 

 tution in 1805, and the tables for predicting the position of the planet 

 were immediately adopted by the nautical almanacs of England, Ger- 

 many, and this country, and afterward by that of France, so that tha 

 computations of Neptune's motion are now generally made from them. 



The elements of Uranus were next so far corrected by a preliminary 

 investigation, that, with the perturbations already computed, the motion 

 of the planet from the time of its discovery in 1781 until 18(32 was repre- 

 sented within a very few seconds of arc. On collecting the perturba- 

 tions of Saturn there appeared to be considerable discrepancy between 

 the old ones employed in Bouvard's tables and those since computed' 

 b}^ Hansen. As there could be little doubt of the correctness of the 

 latter. Professor ISewcomb accepted them as the basis of a preliminary 

 investigation of the orbit of Saturn, and obtained elements which repre- 

 sented its motion near enough for the i)urpose desired. The elements 

 of Jupiter were found to be sufdciently near the truth. The old com- 

 putations of the ''first-order" of perturbations were then corrected, and to- 

 guard against the possibility of an error the perturbations were then 

 recomputed by an entirely different method. After long study and lab©r 

 2 s 



