Covrespontlents are requested lo he a s bripf as possible. T l~c wviler's ?tame is in all cases req~cired usproof'oJgood f u i t i~. The great comet of September, 1882. A RXORE recent determination of the orbit of this comet tllan those mentioned i r~ No. 57 of Science has been made, and the results may be of interest. 'Po avoid (as far as may be) the errors which arise from the fact that different observers have observed various portions of the nncleus, it was thought best to take a series of observations made at a single observatory. A fine series of over one hundred observations made at Cordoba, and extending from Oct. 17, 1852, to June 1, 1883, was chosen. Up to Peb. 12, the same portion of the nucleus mas observed : this portion afterwards became invisible, and then the estimated centre of the elongated nebnlous mass was taken. By con~paring these observations with an ephemeris compated from a former orbit, three normal places were found, the four observations made in Xay and J u n e being neglected. The dates of these normal places were Nov. 16.0, Jan. 3.0, and AIarch 2.5.0. I t is to be regretted that these observations did not begin in Sept,ernber, so that the first normal place might have been nearer the time of perihelion. Below is the derived system of elements, which is referred to the mean ecluinox of 1883.0, Greenwich N.T.

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