Page:Science vol. 5.djvu/43

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_ ■; is, as 8 natural consequence, inhabited by « difTereiit Tauna : in fact, by n tropical deep- sea faiina. an extension or that of the West Iiidies. Not only the lilc-fisli. but certain crus- taceans, are examples of these. NatiiraUv tbey would he sensitive to cold. Duiing the spring of 18S2. violent and long-coutiuued easterly and northerly winds prevailed, and numerous icehei-gs stranded on the George's Banks just north of the belt. We have every reason for believing that these winds carried the inshore waters, which were naturally cold, but whose temperature had been lowered by the sti-anded bergs, across the border-line and into the wunn area. If this were the case, such delicale animals as the tile-fish could not pos- sibly stand the sudden change which their more hardy neighbors could easily live through. .So il was that the tile-fish and a few other species were eslerminated from these grounds. Al- though the fish- com mission has organized many extensixe expeditions for the sole purjxise of searching after the tile-fish, not a single speci- men has since been found, either of the tile-fish or the other species. Whether or not they still exist in waters more southern is an open question; but we understand that Professor Verrill believes they will be found there. At any rate, il is certain that they are entirely absent fi-om their former haunts, and that, if they do exist elsewhere, many years must elapse ere they inhabit this bank again in abundance. Such sudden changes as these, and local extinction of several species by such

I'mple means, cannot help throwing much light ^n paleontolt^cal geology. Ram-ii S. Tabr. ■c.

��ICOUETS AND ASTEROfDS OF 1884.

��I WtriLX the year 1S84 has brought no i^ometa of reniwkable brllliaiicy or popular luterest, compared vith [he comet! of 1881 or 1382, nearlj all the comets o( the year will dftlm mora tlian ordinary attention at the hands of utroiinmers, on account of the interest which attaches lo the investigation of tlielr orbtla. Of the five comets seen, four have been periodic.

The Qrst comet which was discovered in 1884 be- longs properly with the coroel* of the preceding year, as it [MKsed perihelion on Dec. •Hi, 1SS3. It was discovered, however, on Jan. 7. 1884, by Itoas, an ama- l«lir observer, at Elaiernwick, uear Melbourne, Aus- tralia.— "a taint nebulous object, with an iil-defiiied central condensation, and a small, tail-like projec- tion.'' It was not visible in the northern hemisphere, and was under observation for only about a tnonlli. Th e t^l was one and a balE degrees long on Jan. 18,

���NCH. 31

The Qrst comet of 18S4. in order of perihelion pas- sage, was that discovered, or rather re-dii^covered, by Broolta, at rhelp», N.Y., on Sept 1, 1883. It has been commonly known as the Pons-Brooks cornel, or Pons comet of 1812, having been originally discovered by Pons at MsrselJles In that year. An account of this comet has already appeared in Setince (iii. 6T|.

The second comet, in IwLli order of perihelion pas- sage and of discovery, was that found by £. E. Bar- nard of NashvilJe, Tenn., on July 16, 16(4. At the time of discovery it was a nebulous object, slightly condensed near the centre, and tolerably bright. It was found to move in an elliptical orbit with a period of about live and a balf years, the elements bearing a very close resemblance to those of DcVico's comet (1844, i.). The comcIB do not, however, appear to be identical. The nearest approach to the sun was on Aug. IH.

The third comet of JS84 was di»^covered on Sept IT, by Wolf, a student at Heidelberg, and is still under observation. In lis physical appearance, the comet has changed very little since discovery. As far as I know, It has not at any time been viribie to the naked eye, nor has it shown any indications of a Uil. Wheu examined on Nov. 1.3. with the nine- inch equatorial at the Nnval observatory, under a magtiifying-power of one hundred and two diame- ters, It presented the appearance of a 'slightly oval, nebulous object' Near the centre of the nebula was a bright disk nearly circular, anil in the centre of this disk the stellar nucleus. The line of demar- cation between the disk and the surrounding nebula was, of course, extremely uncertain; but measures made with the filar micrometer gave, roui^hiy, a di- ameter of l'52"fortheoutor«ebula, and a diameter of IS" for the central disk. Using the distances given In Knieger's ephemeris, these measures would represent distances of forty-seven thousand and seventy-five hundred miles respectively. By far the most interest- ing feature of the comet is its orbli. Krueger has assigned a period of about six and sevenlh'ieotbs years, but there Is no evidence of any previous appear- ance. He remarks that at the returus in 1871 and 1878 It was unfavorably situated. In 1801 and IStii Its situation is favorable, If we can suppose that it fol- lows the same path as at present. Krueger points out, furthermore, that In the early part of 1875 the comet must have suffered considerable perturbation by Ju- piter, and before that time it may have been following an entirely different orbit. Perihelion was passed on Sept. 20.

Eucke's comet, the moat Interesting short-period comet, has just been reported by Professor Voung. It la extremely faint, but will grow somewhat brighter. It will not reach perihelion till March, 1885.

To complete the list, we should mention a 'sus- pected ' comet to which some interest Is attached. A faint, round, nebulous object was found by Spitaler with the twenty-seven inch refractor of the Vienna observatory, while searching for comet 1S5S, iii.. on the moniiiig of May 28, 1834. Unfavorable weather prevented a re-exam I nation of this place till June 17 aud IS, when the object could no longer be seen, nor

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