35, 36 Capt. CLARKE: Note on the Figure of the Earth. 37, 38 20 = The numerical values of u and v are,04151; + 0·9970 this series of photographs enabled M. Liais to conclude that at the intended central station, the centres of the two bodies passed within 15. The remainder of the account, consisting principally of from which we obtain the following results,— meteorological details, may be left for future and more sufficient publication. Note on the Figure of the Earth. By Captain Clarke, R.E. The geodetical operations executed in India extend from 8° 10' north latitude to 29° 30'; those in Europe from 38° 40′ to 70° 40'. The hitherto existing gap of nine degrees is now half filled up (though in the opposite hemisphere) by the valuable results of Mr. Maclear's measurement at the Cape, given in the last number of the Monthly Notices of the Royal Astronomical Society. I propose to examine the effect of this new are in modifying the results obtained for the figure of the earth at page 771 of the Account of the Principal Triangulation of Great Britain and Ireland, referring to that work for the method of calculation. If we assume for the radius of curvature of the meridian the expression a = 20926364 20855340 b then if x be the necessary correction to the latitude of the north end, the corrections to the latitudes of the other stations will be as follows: or, from which These semiaxes exceed those given at p. 771 of the Account, &c., by 2 and 19 feet respectively. We have, therefore, this interesting result, that the very slight modification in the elements of the earth's figure and dimensions due to the arc at the Cape is entirely owing to the extraordinary disturbance of the vertical line at Kamies Berg. On the Development of the Disturbing Function in the Lunar Theory. By A. Cayley, Esq. The development of the disturbing function for the lunar theory is effected in a very elegant manner in Hansen's Fundamenta Nova, but a further step is requisite to exhibit the result in a perfectly explicit form and to compare it with those of other geometers. To do this is the immediate object of the present memoir, the mode of development being a reproduction of that made use of by Hansen. The results are compared with those obtained by Lubbock and Pontécoulant. But the memoir is written with a view to the development and application to the lunar theory of the theory contained in the author's "Memoir on the Problem of disturbed Elliptic Motion," and the notation is consequently that of the memoir just referred to. rays, The solar eclipse of Sept. 7, 1858, was observed at the Isle of St. Croix, Danish West Indies, by Major Lang. The last contact occurred at 21b 9m 18s local mean time. The sky was free of clouds, but the direct heat of the sun's about 130°, was almost insurmountable. No appearance of Baily's beads nor any other remarkable phenomenon. The atmosphere pure and clear. A very large spot with an extensive cluster on the sun's south-west quadrant, the whole length of which the day before was computed to be about 75,000 English miles. The following note is by Mr. Williams, the Assistant-Secretary of the Society : "This morning, about twenty-five minutes past eleven, chancing to look at the sun, which was at that time greatly obscured by a fog, I distinctly saw without optical assistance what appeared to be two spots very near each other, a little below the equator of the sun towards the west. Upon applying the telescope my conjecture was verified, two large spots appearing in that place and another above the equator towards the east. This last I was unable to perceive without the telescope. There were also five or six smaller spots visible in the instrument. "Nov. 10, 1858." Note on the Nomenclature of the Minor Planets. A few months since my attention was directed by Sir John Herschel to the inconvenience and confusion which are being gradually introduced into the nomenclature of the minor planets by the acceptance of names, easily mistaken either in speaking or writing for others belonging to planets previously discovered. I have been fully sensible of the liability to error or misapprehension thereby induced, and am desirous of recording a protest against any further continuance of what must eventually become a positive nuisance to those who are more particularly occupied with the observations and calculations bearing upon this numerous group of planets. Thus we have already : Thetis, Themis; Lutetia, Lætitia; Iris, Isis; Vesta, Hestia; Pallas, Pales. It will naturally be the wish of every discoverer of a planet that his enfant trouvé should be known to posterity by the name which it has borne during his lifetime; but if the practice to which allusion is here made be suffered to continue much longer, there is certainly a probability that a day will arrive when, for the sake of their general convenience, astronomers will consign these troublesome names to oblivion, and substitute others less liable to engender confusion. This consideration alone, we might suppose, would prove sufficiently powerful to induce hesitation on the part of the discoverer before accepting any name likely to be objected to on the score of similarity with that of a planet previously found. Nov. 11, 1858. Letter addressed to the Secretary by Sir J. F. W. Herschel. Read and published by his request. "In the fourth edition of my Outlines of Astronomy, p. 337, in which the discovery of Hyperion (Saturn's eighth satellite) is mentioned as there recent, the discovery is attributed to Mr. Dawes and Professor Bond, without any mention of Mr. Lassell, in whose observatory and with whose instruments, by the joint observations both of Mr. Lassell and Mr. Dawes, the discovery was made. "The passage was written very hastily, in the absence of any possibility of reference to books or letters, and under the urgency of very pressing public business, and has, unfortunately, been passed uncorrected in the new edition of that work recently published. My attention having been drawn to the point by a mutual friend of all the parties, I think it due to them, as well as to the Society to which I have the honour to belong, to offer this explanation of what must otherwise appear a singular piece of injustice." There were exhibited at the Meeting a series of stereoscopic photographs of the moon, which had been executed in the first instance by Mr. De La Rue, and were subsequently enlarged by Mr. R. Howlett to eight inches diameter from the original negatives. The stereoscope in which they were viewed was manufactured by Messrs. Smith, Beck, and Beck. The instrument was of similar construction to Wheatstone's reflecting telescope; but the objects being transparent, the usual arrangements and adjustments were considerably modified. Prisms with slight curvatures worked on the surfaces were employed instead of mirrors for combining the pictures. The photographs were capable of being resolved; and the illumination was effected by Tyler and Son's new Belmontine lamps, large mirrors being provided for daylight. The appearance of rotundity over the whole surface of the moon is perfect; and parts which are as plane surfaces in the single photograph in the stereoscope present the most remarkable undulations and irregularities. By desire of Mr. De La Rue, the instrument is now on view at Smith, Beck, and Beck's, 6 Coleman Street, where it can be seen through by any one interested in the subject. RECENT PUBLICATIONS. The Nautical Almanac for 1862 has recently been published. The usual Supplement containing the ephemerides of the minor planets for the proximate year, appears in a separate form, the Lords Commissioners of the Admiralty having ordered that the volume itself shall be published more in advance than hitherto. By this arrangement the Supplement is published a little later than the volume, but purchasers of the latter may obtain the former by applying any time before the end of 1859, at the Nautical Almanac Office, 3 Verulam Buildings, Gray's Inn, London. Astronomical and Meteorological Observations made at the Radcliffe Observatory, Oxford, in the year 1856, under the superintendence of Manuel J. Johnson, M.A., Radcliffe Observer. Vol. XVII. Oxford, 1858. This volume commences as usual with the observations made with the transit instrument and the meridian circle. Then follows a catalogue of the stars observed in the year 1856, showing the result of every observation. The number of stars is 1368. The astronomical part of the volume closes with a provisional catalogue of 1481 stars, deduced from the observations made at the Radcliffe Observatory during the years 1854-5-6, reduced to 1860'0. This catalogue, to which allusion has already been made in the Monthly Notices, is designed to comprehend all objects in the heavens beyond the solar system which are supposed to be affected by some physical peculiarity, or to which other circumstances lend more than ordinary importance. In its present form the Catalogue is not a completed work. It merely represents the progress of the undertaking down to the year 1856. The following are the classes of objects which in its ultimate form it is intended to include: 1. Stars above the third magnitude. 2. Stars situated within 6° of the north pole, which can be conveniently observed with telescopes of 4-inch aperture. 3. Stars which are, or are supposed to be, variable, or which present unusual appearances of colour. 4. Stars which are, or are supposed to be, affected by proper motion exceeding o" of the great circle. 5. Double stars known to be affected by orbital motion. 6. Stars of whatever magnitude contained in the standard catalogue of the Nautical Almanac, as well as those whose places are used for comparison with the moon. Mr. Johnson has appended to the present provisional Catalogue a list of stars which differ more than 0.5 in R.A., and 4" in N.P.D. from those in the British Association Catalogue. It is plain from the notes which follow this list that the discordancies are in most instances attributable to an erroneous proper motion adopted in the construction of the British Association Catalogue, resulting generally from a comparison of only two determinations. The Catalogue contains a table of variations and epochs of the variable stars, compiled by Mr. Pogson from his own observations, and from the publications of other observers. Détermination des Orbites des Planètes et des Comètes. The author first gives a general explanation of the method for determining the orbit of a planet or comet founded upon employing no more observations than the number which is mathematically necessary for the purpose. He then gives a similar exposition of the method employed by himself, which consists in obtaining expressions in a converging series depending on the time, for the geocentric longitude and latitude of the planet or comet, founded on an indeterminate number of observations made during a short interval of time; and then, by means of those expressions, and the results of their successive differentiation, combined with the differential equations for the motion of a body revolving in a conic section, determining the heliocentric distance, and the velocity and direction of motion of the body at a given instant, these being the fundamental circumstances of motion from which the elements are readily deducible. The principle of this method, it will be seen, is the same as that used by Laplace in his solution of the same problem, but M. Villarceau has pointed out and skilfully discussed the various circumstances which render a modification of the form of solution indispensable, and has given convenient formulæ applicable to each particular case. He has also shown how the elements may be rectified by a process of approximation founded on applying successive corrections to the coefficients of the expressions for the geocentric longitude and latitude, the values of these corrections being obtained by the solution of a system of linear equations. The author, at the close of his investigation, gives numerical applications illustrative of several cases of the problem considered by him. *"Extrait des Annales de l'Observatoire Impériale de Paris," tome troisième. 42, 43 Descrizione del Nuovo Osservatorio del Collegio Romano D.C.D. G., E Memoria sui lavori eseguiti dal 1852 a tutto Aprile 1856, del P. Angelo Secchi, D.M.C., Roma, 1856. This volume commences with an historical account of the Observatory of the Collegio Romano. The author then gives a description of the New Observatory, and the principal instruments with which it is furnished. These consist of a meridian circle by Ertel, two feet three inches in diameter, a small transit-circle by Reichenbach, a refractor equatoreally mounted, by Merz, having a clear aperture of nine French inches, and a sidereal clock by Dent. Professor Secchi contemplates devoting the resources of the observatory to the advancement of stellar astronomy. For this purpose the great equatoreal chiefly claims his attention. This fine instrument was first erected in the new observatory in the month of October 1854, and has already done good service in the hands of the distinguished Director of the establishment. The second part of the volume is devoted to an account of the observations made during the period referred to in the title of the work. The first section contains a series of micrometrical measures of double stars with the great refractor, and a comparison of the results with those of other observers. Then follow, in the second and third sections, observations of nebulæ and clusters of stars, with remarks upon the zodiacal light. The fourth section is devoted to micrometrical measures of Saturn and his rings, and the fifth to physical observations and micrometrical measures of Jupiter and his satellites. In the sixth section the author determines the latitude of the observatory, which he finds to be 41° 53′ 53′′72. The seventh section contains miscellaneous observations on the spots and temperature of the sun, on selenography and on the colours and scintillation of the stars. The eighth and ninth sections are devoted to meteorological and magnetical observations. In an appendix the author has inserted some cometary and planetary observations; also additional measures of Saturn and observations of the planet Mars. Zweijahrige Beobachtungen der Meisten jetzt Bekannten Veränderlichen Sterne. Von J. A. Č. Oudemans.* In this paper Dr. Oudemans gives the details of observations of most of the known variable stars, made by him at the Observatory of Leyden during the years 1854 and 1855, and part of the years 1853 and 1856. The method employed by him, which is due to Argelander, is founded on a series of comparisons of the light of the variable in each instance with that of certain stars in its vicinity. The paper contains a discussion of the observations of 3 Lyre and d Cephei, and the deduction of the definitive results with respect to the epoch and period of each star. The author has also given a graphical representation of the variations of the light of each star, and has instituted a comparison between his results and the corresponding light curves of Argelander and Heis. * Verhandelingen der Koninklijke Akademie van Wetenschappen, Derde Deel, 4to., Amsterdam, 1856. ERRATUM. Vol. XVIII. No. 5 for March, 1858, page 140, in the Apparent N.P.D. of Irene, Jan. 28, for 77° 20′ 36" 84, read 77° 20' 28" 83. Letter from Mr. Maclear to the Astronomer Royal. "I herewith send the observations made on D'Arrest's comet. By the same post I forward a copy of them to M. Villarceau of the Paris Observatory, who wrote to me respecting them. "It was a very faint object, partly owing, perhaps, to the line of sight being through the Kloop that separates the Lion's Head from the Table Mountain. When I detected it all light had been excluded from the equatoreal room for some fifteen minutes, otherwise perhaps it might have escaped; and when occasionally I looked during the series of observations afterwards, the image was never brighter than at first. Making due allowance for the low altitude, and the direction along the north edge of the Table Mountain cap, my impression is, that in the search for it hereafter the object-glass should not be less than six or seven inches." Underneath are the observations referred to in the foregoing letter: Right Ascensions and North Polar Distances of D'Arrest's Comet observed at the Royal Observatory, Cape of Good Hope. By T. Maclear, Esq. Cape Mean Time. No. Cape of Mean Date. Star. Time. Difference in R. A. 1857. h m S m 8 R.A. of Comet. h m h m S 8 49 5'3 I 13 20 IO 21 20 13 30°22 20 13 33.65 20 31 4'04 20 31 6.36 '7732 3 *7724 IO 10 *7737 *7715 5 *7727 9 14 8 57 52'1 16 7 43'01 4 51 39 4 58.04 5 3 27 8 3.23 + 7 4'76 110 + 0 47°76 9 5 30.8 II 8 53 19.6 + 0 52.01 109 55 19'4 8 47 52'4 + 4 23.15 109 46 35'4 2 53.6 + 7 40'44 8 55 9.6 1 44.81 -11 30°44 + 4 14.65 3 254 III 3 19'9 IIO 44 44 8 110 44 38.1 110 38 55.6 110 19 0.8 110 18 54'1 3 35'7 109 27 57'0 *7222 17 107 21 18.6 107 7 56.3 106 40 22.7 105 57 30'1 |