* LIBRARY in- run ^nioersittJ af ^alif REFERENCE. No Division Range Shelf / Received ••' ,<:;'-;: -;'. v;t--- • ..I ' «• ; - • J , - ••• A'/;: ;•'"'-'•• •: v •--- -"--i •- \ •- ^H ., - ,. • - ':' " - • • . : " •' •••• ' ' ••• -:. '" ' • "• -.<•.•„ • . ••-:. :-••-:- • „ M -. '.'"-' ••> •;, : ."' -.---/ -. ••- . - . ,,• . ,.,, •'• i • --• ,-i.; ,-'. ', i ^, • .- _• - Rt« - - ....•_> • : •..••,'- : . -.- ••• • • ' ' ^ i^vhii, :- - "'(, SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE. . 199 AN INVESTIGATION OF THE ORBIT OF NEPTUNE, WITH GENERAL TABLES OF ITS MOTION. BY SIMON NEWCOMB, PROFESSOR OF MATHEMATICS, UNITED STATES NAVY. [ACCEPTED FOB PUBLICATION, MAY, 1865.] COMMISSION TO WHICH THIS PAPER HAS BEEN REFERRED. Admiral C. H. DAVIS, U. S. N. Prof. STEPHEN ALEXANDER. JOSEPH HENRY, Secretary S. I. COLLINS, PRINTKB, PHILADELPHIA. TABLE OF CONTENTS. CHAPTER I. INTRODUCTION. SECT. PAGB 1. Introductory remarks . . 1 2. Account of Walker's theory ....... 1 3. Account of Kowalski's theory ....... 3 4. Form of Kowalski's equations of condition, and origin of the difficulties arising from it .......... 4 5. Objects of the present investigation ...... 6 CHAPTER II. PROVISIONAL THEORY OF NEPTUNE. 6. Formulas for the perturbations of longitude and radius vector ... 8 7. Formulas for the perturbations of latitude ..... 10 8. Secular variations ......... 13 9. Theory of the action of an inner on an outer planet through the Sun . 13 10. Development of the preceding theory according to the powers of the ratio of the mean motions ......... 16 11. Method of treating the long-period perturbations of the elements produced by Uranus .......... 19 12. Adopted elements, masses, and constants of theory, for perturbations . 20 13. Computation of the perturbations by Uranus, Saturn, and Jupiter . . 22 Action of Venus, the Earth, and Mars ...... 31 14. Indirect perturbations by Saturn .... 31 15. Collection of the long-period and secular perturbations of the elements . 32 16. Collection of the perturbations of the co-ordinates — Comparison with Peirce and Kowalski ...... 33 17. Formulas for computing an ephemeris . . 36 18. Elimination of the elliptic terms ...... 36 19. Elements and formulas of the provisional theory . . . . .38 20. Heliocentric and geocentric positions resulting from the provisional theory . 41 CHAPTER III. DISCUSSIONS OF OBSERVATIONS OF NEPTUNE. 21. Choice of observations, and method of discussing them . . 44 22. Reduction of Lalande's observations, May 8-10, 1795 . 45 23. Probable error and value of the Lalando positions . • . .49 24. Method of treating the modern observations . . . 49 25. Mean corrections of ephemerides of Neptune, given by different observatories . 51 26. Investigation of the systematic differences between the results of different obser- vatories . ..... 53 i TABLE OF CONTENTS. SEPT. PAGE 27. Concluded Normal Eight Ascensions and Declinations . . . 5(J Systematic discrepancies still remaining between different authorities . 61 . 28. Longitudes and latitudes compared with the theory . . . .62 CHAPTER IV. RESULTS OP THE COMPARISON OF THE THEORETICAL WITH THE OBSERVED POSITIONS OP NEPTUNE. 29. Formulas for corrections of the elements ..... 65 30. Equations of condition — Method of treating them . ... . .67 31. Solution of the equations — Residual errors ..... 70 32. Impossibility of correcting the mass of Uranus . . . . .72 33. Impossibility of yet detecting an extra-Neptunian planet — Almost perfect accord- ance of theory with observation during the nineteen years of observations . 72 34. Position of the plane of the orbit ...... 73 35. Concluded corrections and final values of the elements of Neptune . . 74 CHAPTER V. TABLES OP NEPTUNE. 36. Fundamental theory on which the tables are founded ... 76 37. Data given in the several tables ...... 77 38. Elementary precepts for the use of the tables ..... 82 39. Examples of the use of the tables ....... 84 Tables 88-110 ON THE ORBIT OF NEPTUNE. CHAPTER I. INTRODUCTION. THE errors of the published ephemerides of Neptune are now increasing very rapidly. In 1SG3, Walker's ephemeris was in error by 33", and Kowalski's by 22". Both ephemerides may be 5' in error before the end of the present century. The orbit of this planet is, therefore, more uncertain than that of any other of the larger members of our system. The uncertainty arises from the insufficiency of the data at the command of those astronomers who have hitherto investigated the motions of this planet. These motions are so slow that it is impossible to determine the elements of the orbit with accuracy from observations extending through only a few years. In Walker's investigations the errors of observation are multiplied more than a hundred times in the elements deduced from them, on account of the smallness of the arc through which the planet had moved. The time has now come when the orbit can be determined with some approach to accuracy. The planet has moved through an arc of nearly 40° since its dis- covery, and the errors of observation will be multiplied only ten or twelve times in the errors of the elements. In commencing the work of a revision of the theory of Neptune, it will be well to glance at the past and present state of our know- ledge on this subject. Approximate elements of this planet, neglecting the effect of perturbations, were computed by several astronomers within a year or two after its discovery. But the work of preparing a theory which should include the perturbations produced by all the other planets seems to have been left entirely in the hands of Professor Peirce and Mr. Sears C. Walker. § 2. All the first approximations to the elements showed that the mean motion was very nearly half that of Uranus. It was, therefore, for some time doubtful whether the mutual action of the two planets might not be such as to render the period of Neptune exactly double that of Uranus, and thus present us, on a much grander scale, with a phenomenon similar to that exhibited by the satellites of Jupiter. Professor Peirce's first perturbations of Neptune were computed on this hypothesis, and published in the Monthly Notices of the Royal Astronomical Society, Vol. VIII, p. 40. The eccentricity of Neptune was neglected, but that of the disturbing planets was included in the perturbations. With these perturbations, the ancient observations of Lalande, and the vast number of modern observations made in nearly every active observatory in the world during 184G and 1847, Mr. Walker computed his "Elliptic Elements I." of 1 May, 1865. 1 2 THE ORBIT OF NEPTUNE. Neptune. The longitude of perihelion referred to the mean Equinox of Jan. 1, 1847, eccentricity, and mean daily motion were as follows : n = 48° 21' 2".93 e — .00857741. n - 21".55448. This mean motion rendered it certain that the supposed relation between the mean motions of the planets Uranus and Neptune had no foundation in fact. Professor Peirce thereupon revised his theory, and published the new perturb- ations in the Proceedings of the American Academy, Vol. I, p. 286. The near approach to commensurability of the mean motions renders the general theory of the mutual action of Uranus and Neptune extremely complex. Twice the mean motion of the latter exceeds that of the former by only 320" according to Walker, or 304" according to my first revision of his elements. The terms in the perturbations which contain this very small quantity as a divisor will, therefore, be very large. Considered as perturbations of the elements, their period will be more than 4000 years. We have an analogous instance in the 900 year equation of Jupiter and Saturn. But in the latter case the perturbations of the mean motion are of the third order with respect to the eccentricities and inclinations, while in Uranus and Neptune they are of the first order. From this circumstance it happens that, notwithstanding the smaller masses of the dis- turbing planets, the perturbation of the mean motion is as great in the case of the planets in question as in that of Jupiter and Saturn, and that of the other elements enormously greater. In fact, the perihelion of Neptune oscillates through a space of eight degrees in consequence of the terms in question. Such a perturb- ation as this, four degrees on each side of the mean, is, I think, found nowhere else in our system. Moreover, a change of 1" in the mean motion of the planet will produce a change of nearly 2' in the coefficient of this perturbation. Any attempt to determine its magnitude with accuracy will, therefore, be hopeless. But the difficulties connected with these terms can be avoided in the case of a theory which is designed to be exact for a period of only a few centuries. Not- withstanding the great magnitude of the general integrals of the perturbations, if we take these integrals between limits not exceeding a couple of centuries, we shall find them so small as not to involve serious difficulty. Their effect on the co-ordinates can then be developed in powers of the time, and the values thus obtained will not be subject to any uncertainty of moment. This is substantially the course adopted by Professor Peirce. He says of the terms in question : " These coefficients will vary very sensibly by a change in the value of the mean motion of Neptune, arising from a more accurate determination of its orbit. But the principal effect of these terms can for a limited period, such as a century, for instance, be included in the ordinary forms of elliptic motion, and the residual portion will assume a secular form which is no more liable to change from a new correction of the mean motion of Neptune than the other small coefficients of the equations of perturbations." Accordingly, subducting from the terms in question a series of expressions THE OKBIT OF NEPTUNE. 3 which would result from arbitrary changes in the elliptic orbit, there is left a small residual, mostly developed in powers of the time, and only amounting to a few seconds in a century, which alone is retained. With the new perturbations, and revised normal places of Neptune, Mr. Walker obtained the following final set of elements, which he denominated Elliptic Ele- ments II.: 7i = 47° 12' 6".50 £1= 130 4 20 .81 = 328 32 44 .20 1 46 58 .97. e =.00871946. It — 21".55448. Epoch, Jan.l, 1847. From these elements and perturbations we have a continuous ephemeris of Neptune since the time of its optical discovery. From 1846 till 1851 inclusive, this ephemeris is found in the Appendix to Vol. II of the Smithsonian Contri- butions to Knowledge ; for 1852, in Vol. Ill of the same series, and also in the Astronomical Journal; and for subsequent years, in the American Ephemeris and Nautical Almanac. All the modern observations on which these elements were founded were made in the yetars 1846-47, while the planet was moving over an arc of only two and a half degrees. Considering that the complete determination of the elements requires, effectively, four observed longitudes, all in different parts of the orbit, and that three of these positions are included in a space of less than three degrees, it must be admitted that an accurate determination of the elements was, under the circumstances, impossible, owing to the imperfections of the observations. As already remarked, the errors of observation would be multiplied several hundred times in the elements. Hence, with the best possible observations, the elements would be uncertain by one or more minutes. But the observations themselves were mainly differential ones; and it is very doubtful whether the positions of the stars of comparison were as well determined as the position of the planet itself could be determined by a series of good meridian observations. § 3. The theory of Neptune was next taken up by Professor Kowalski, of the University of Kasan. His work was published under the title of " Eeclierc1t.es sur les mouvements de Neptune, suivSes des tables de cette planete, Kasan, 1855." The long-period perturbations of the elements are here developed, in their general form, as perturbations of the co-ordinates. There are, therefore, a much larger number of terms having large coefficients in this theory than in that of Professor Peirce. Owing to this change in the form of the perturbations, the two theories cannot be directly compared. But the ephemerides resulting from each theory can be compared directly with observation, and corrections of the elements thence ob- tained. It is thus found that the elements in question require, approximately, the following corrections in order that the ephemerides may agree with obser- vations to 1863 : 4 THE ORBIT OF NEPTUNE. Theory of Walker. Theory of Kowalski. %n _ 4° 11' • _ 4° 12' " Se — 0 0 52 — 0 0 51 & — 0 3 6 2 53 Sn 8.4 8.5 Thus, it seems that the theory of Kowalski is, on the whole, no nearer the truth than that of Walker, although it was founded on observations up te 1853, when the planet had moved through an arc of sixteen degrees since its optical discovery.* The cause of this failure to derive a more accurate result is an accidental mistake in the computation of the perturbations of the radius vector by Jupiter, as I have more fully pointed out in the Monthly Notices of the Royal Astronomical Society for December, 1864. § 4. The form which Professor Kowalski finds his equations of condition to assume is illustrative of an interesting and important principle of the method of least squares. By the comparison of his provisional theory with observations, forty-four equations of condition are obtained for the corrections of the four elements 7t, e, e, and n. It is then inquired whether it is possible to determine the orbit of Neptune from the modern observations alone, omitting that of La- lande, the planet having moved through an arc of sixteen degrees. Treating the equations derived from the modern observations alone by the method of least squares, four normal equations are obtained. Two of these equations are, omitting the terms involving the correction of the mass of Uranus, which we do not need, — 10.4994 jn — 21.2GG1 8s + 13.0QS8 e%n + 40.2211 «e - — 324".65, 26.9661 3n — 73.2702 & + 40.2211 e&n + 139.9907 fe = — 886 .63, and the other two can be transformed into the following : — 10.4994 in — 21.2661 be + 13.0073 efa + 40.2219 & = — 324.50, — 26.9661 hi — 73.2702 fc + 40.2219 efa + 140.0009 be = — 886.77. It will be seen that the last two equations are very nearly identical with the first two. Hence it is concluded that the modern observations alone give only two independent relations between the four unknown quantities sought, and do not suffice, therefore, to determine the elements of Neptune. Now, the identity in question does not prove that the modern observations are insufficient to determine the elements, because it is the necessary result of tltc ///<>i/r. of treating equations of the kind in question by tlie meffuod of least M/tuircx. This can be most easily shown by a theorem in determinants. By the elementary principle of determinants, if we have a number of linear equations between the same number of unknown quantities, of the form * The differences of the two values of An and Se, which are so small, do not correctly represent the absolute differences of the two theories, owing to the great difference of longitude of perihelion in the two theories proceeding from the different forms given to the perturbations. The real difference Kowalski — Walker is given Ijy the equations <).e8in7r=+ I", fi.e cos it = — 13. THE ORBIT OF NETTUNE. i» + % + CjZ + etc ..... = «!, «2x + % + c.2z + etc ..... rr n.,, etc* etc. etc. etc. etc.; each unknown quantity is given in the form etc., in which R represents the determinant formed from all the coefficients a, b, etc. in the given equations, and A1} A.2, etc. the partial determinants, obtained by omitting column a, row 1, column a, row 2, etc. If, now, the number of equations is greater than that of the unknown quantities, and they are solved by the method of least squares, the form of the solution will be the same as the above, except that for R will be substituted the sum of the squares of all the determinants R, formed by solving separately every combination of such number of the given equations as is equal to the number of unknown quantities, and for Al} A.2, etc., certain powers and products of the partial deter- minants which enter into the separate solutions. Hence, if these determinants are very small, the corresponding determinants in the solution by least squares will be very small quantities of the second order. But the determinants will all be very small if the equations are nearly equivalent to a number less than that of the unknown quantities ; that is; if they can be put into the form rp aX+ (3Y+yZ+ etc. + p = n4, a'X+ @'Y+ yZ+ztc. + p' = «6, etc. etc. etc. etc. etc. etc.; the quantities X, Y, Z, etc. being less in number than the unknown quantities, and p being a very small linear function of the unknown quantities. If the p's vanish, all the determinants will vanish with it ; whence, if they are very small, the determinants will be very small likewise. Calling a system of equations identical when they really give fewer independent relations than there are un- known quantities, the theorem sought may be expressed as follows : If a system of equations differ from identity by a very small quantity, the normal equations derived from them ivill be identical to small quantities of tlie second order. Hence, if such a system of equations is to be solved by least squares, it will be necessary to carry the solution to nearly twice as many decimals as are necessary in the original coefficients. Thus, in the case under consideration, as Professor Kowalski considered it necessary to retain four places of decimals in the coefficients of the unknown quantities, it would have been necessary to include at least six or seven decimals in the normal equations, instead of only four. But the necessity for so long a numerical calculation can be avoided by a suitable transformation of the equations of condition. If the equations are identical, they really give certain linear functions of the unknown quantities less in number 6 THE ORBIT OF NEPTUNE. thcin the unknown quantities. We may then substitute these linear functions themselves in place of an equal number of the unknown quantities. If the equations are not absolutely identical, the coefficients of the other unknown quan- tities will not entirely vanish by the substitution, and thus we shall still have the whole number of unknown quantities, only the coefficients of certain of them will be very small. The solution by least squares can then be performed without trouble, because the extra decimals will be necessary only in multiplying by the very small coefficients, when they can be introduced with ease. Afterward the values of the original unknown quantities can be deduced from those of the linear functions, and the unknown quantities which have been retained. Suppose, for example, that the equations of condition are aft -\- It^j -\- CjZ — TO! a.2x -f- cnz = nn A simple inspection, or, at least, an attempt to solve three of the most diverse of the equations, will show if the given n equations are really equivalent to only one or two. Then we should put X— ax + $y + yz the coefficients a, /?, y, being entirely arbitrary, and so taken that when X and Y were substituted for x and y the coefficients of z should be as small as possible. It would conduce to simplicity if a and /?', or a' and /?, could each be made zero, which could always be done. If we attempt to correct the elements of a planet's orbit by observations extending over only a few degrees, the equations of condition will necessarily be of the kind referred to. Hence a transformation of this kind will be advisable. An example will be given in the correction of the orbit of Neptune from observation. § 5. Ten years have elapsed since the publication of Kowalski's theory, and no general revision of the orbit has been published by any astronomer, so far as the writer is aware. The observations which have accumulated in the mean time would seem sufficient to fix the elements exactly enough to give the place of the planet within 5" during the remainder of the present century. It is, therefore, proposed, 1. To determine the elements of the orbit of Neptune with as much exactness as a series of observations extending through an arc of forty degrees will admit of. 2. To inquire whether the mass of Uranus can be concluded from the motions of Neptune. THE ORBIT OF NEPTUNE. 7 3. To inquire whether those motions indicate the action of an extra- Neptunian planet, or throw any light on the question of the existence of such a planet. 4. To construct general tables and formulas by which the theoretical place of Neptune may be found at any time, and, more particularly, at any time between the years 1COO and 2000. In giving the steps of an investigation like this, the true end should be to furnish the means whereby every step can be corrected, or verified if already correct, and to start only from admitted data. Sometimes a result will necessarily depend, to a certain extent, on an act of judgment, as in assigning relative values to different determinations of the same element. In this case data should be given for a revision of the judgment, as far as this may be thought desirable. Such, with very few exceptions, is the rule adhered to in the present paper. The data are the published volumes of astronomical observations, and the funda- jnental formulae of celestial mechanics. The steps will nearly or quite always be so short that any one may be verified from the preceding one without much labor. The author is indebted to the courtesy of the Astronomer Royal, of the late Captain James M. Gilliss, and of Professor G. W. Hough, for the observations made at Greenwich, Washington, and Albany in the years 1863 and 1864, which have added greatly to the reliableness of the results of his investigation. WASHINGTON, April, 1805. THE OIII3IT OF NEPTUNE. CHAPTER II. PROVISIONAL THEORY OF NEPTUNE. § 6. ALL the perturbations have been computed by formulae founded on the method of La Grange ; the development of the perturbative function in series, and the variation of arbitrary constants. The following notation is used : I rz mean longitude. /I — mean longitude, counted from ascending node of inner planet on outer one. <£> rz inclination of orbit to the ecliptic. ) U in which i, i', j, and/ are numerical coefficients. 7i is a function of the ratio of the mean distances, the eccentricities, and the mutual inclination of the orbits. Then, by the theory of the variation of arbitrary constants, any term of the perturbative function in the action of an inner on an outer planet will cause the following differential variations of the four elements which determine the form of the orbit, and the position of the planet in it. Putting e — sin 4> (j rz cos ^ tan | ^ ; we have ^- — — 2 mi'ha'ri sin N. dt ( <11> dh ) - >• cos N, ( 1 ) da f dt' YJd^^ "c -j— zz mn'h •] /' cot A//' + *y [ sin ^ it t V / f/Tt' ,/77i -77- zz mn' cot -f -r- cos N. dt dd THE ORBIT OF NEPTUNE. 9 From the first equation and the relation between the mean distance and mean motion, we obtain 3£zz9irf&ffim*y> dt These equations are entirely rigorous, provided that we regard the elements in the second member as variable. But they can be integrated only by successive approximations. In a first approximation the elements are regarded as constant Equations similar to (1) for the elements of all the planets whose action is taken into account being integrated in this way, the resulting values may be substituted in the second members of (1), and a new integration be performed. In the case of Neptune, however, the variations of the elements are so slow that a single approximation will be amply sufficient for a period of several cen- turies, provided that we adopt suitable values of the elements in the second members ; that is, if we add such constants to the integrals that the latter shall n' be very small for the present time. Putting v = - — J i'n'-{-'in we shall have, on the supposition that the elements as they enter into the second member are constant, log a' = mvA cos N-\- a'0, d = mvE cos jV+ e?0, (2) I' = mvL sin N-\- n'0t + e'0, ri zz mvWsin N-{- rf0) A, L, E, and W being given by the equations A = 2 i'h, E= — h(fcoimv { eL — eW+ emv{eL — eW— E}$m.(N— 2/) —etc. +lemt>{eL—eW+E}an(N+2f) (4) + V we should put 7 dh (7x, n — d 'x^; a -7 - = da •=-=• ', da da s7t cot ^ = set*-1 Xl + se's + ' (— J Xl + xa) . * § 7. Perturbations of latitude. The equations which determine the change in the plane of a planet's orbit are dtt a'ri dR _ dt ' ~ sin q>' cos fy dq>' d_ , dR dX dR d^ dR d$ ~ ' ~T~ dti d$ "^ dy dRdR fa dR rfw dR dX dR 'dR THE ORBIT OF NEPTUNE. 11 The values of the second of each pair of differential coefficients can easily be determined geometrically. /I, w, /I', etc., it will be remembered, represent the dis- tance of certain points on each orbit from the ascending node of the disturbing planet on the disturbed one : the infinitesimal changes in those quantities, produced by infinitesimal changes in the position of the plane of either orbit, will be due entirely to the changes in the position of that node. Let us put x1 = distance of common node from ascending node of disturbed planet on the ecliptic. x zz same quantity for disturbing planet. By drawing the diagram, it will readily be seen that by a change in <£>' the common node will be moved forward on the disturbed planet by the amount + sin x1 cot yd' cot ydQ', — cos x" sin <£>' cosec ydff, — sin x' sin We therefore have cZ/l da 1 do' zz —. — -M zz cos x cot y, O I 1-1 ,*' fl(V I ' I do -jfT, — cos x cosec y, dy 1 dy •f-. = — cos x'; -. — , jfe = — sin x'. ' ' '' Also, by the differentiation of the representative term of R, dR mi'h . ,T dR mj'li . ,, -7 - - zz -- r sin N, -T- = -- -- sin N, d% a' drf a! dR mill . ,., dR mjJi . ,r -^- = --- Bin JV, -j— = -- r sin N, dh a' f?u a' dR dR du m dh -j- zz -, -- r~ zz \ —, -T- dy du dy a' du 12 THE ORBIT OF NEPTUNE. Substituting these expressions for the differential coefficients in the values of . ^ and rfr we have - =. — h sin y> sin N { (i' +/') cot y + (i -\-j) cosec y } - -j- cos \y cos it cos N. (id) tt Q> du - (id) 1 dR m — (t sin <£> dQ Let us now put .. , ,. i' +/)co m dli cosecvj — i ~, -r- It may be remarked that i will then be the coefficient of the longitude of the common node of the orbits in the usual development of the perturbative function. The above equations may then be put into the form dR m -I • , • »T m , 1 . f. I 1 • I • AT 1 m 'fa I »7 -r = — —rih cosec y sm / sin N — -7 (V + f) ft tan A y sm x' sin N — 1 — ? -5- cos -1 y cos x cos N. dip a! a ^ a du 1 dR m , . . ,r wi , ,, , . . ,,. m dh -~j- — —th cosec y cos x' sin IV -(- — (tT +/) A tan J, y cos x' sin /v — £ — y cos sin , V = mv { (I— T) cos (N+ T) + (7+ T) cos (N—r) } ; § 8. The equations (2) and (9) determine the periodic perturbations of the elements. For the secular variations, which proceed from those terms of the perturbative in which both i' and •*' are zero, the same expressions apply, only changing v sin JVinto n't Cos N ; v cos JVinto — n't sin N. We therefore have, for the secular variations, dl' -jj- — mri L0 cos N ; de! . -^— — — mn A) sin Jy ; dt = mn'W0cosN; (10) -~- •=. — 2 mn' {I0 sin t sin N-\- T0 cos t cos N} ; U-t ^r — — 2 mn' { IQ cos r sin N — Tu sin r cos N} . ctt Owing to the smallness of the eccentricity of Neptune, it will l>e advisable to substitute the rectangular co-ordinates of the centre of its orbit for the eccentri- city and longitude of perihelion. The perihelion itself is subject to changes so great that it would otherwise be necessary to develop the perturbations to quantities of a higher order than the first. We shall, therefore, put II-=.G sin 7i ; lt — e cos n. For the secular variations of h and k, we then have, to a sufficient degree of approximation, dk sn § 9. Development of the action of an inner on outer planet through the Sun. The perturbations which one planet produces on another may be divided into two distinct parts. 14 THE ORBIT OF NEPTUNE. 1. Those produced by their direct attraction on each other. 2. Those produced by the displacement of the Sun by the attraction of the disturbing planet. The co-ordinates of the disturbed planet being counted from the centre of the Sun, the displacement of the Sun not only changes the value of the co-ordinates by changing their origin, but also by modifying the attraction of the Sun itself. The perturbations of both classes may be included in the same formulas, and the total perturbations computed in the same way that those of the first class are, by a very simple modification of those functions of the ratio of the mean distances which enter into the different values of h. But in the case of the action of an inner on an outer planet more than twice as far from the Sun, this method will be subject to this serious inconvenience; that the perturbations of the elements are many times greater than those of the co-ordinates. Referring to formulas (4) and (5), it will be remembered that L, E, and W really express per- turbations of the mean longitude, perihelion, and eccentricit}r, and it will be seen that the perturbations of the true longitude fe are expressed as a function of the perturbations of those elements. Now, having in this way computed the perturb- ations of any co-ordinate which depend upon the different terms of the perturbative function, when we collect those coefficients which are multiplied by the sine or cosine of identical angles, we shall frequently find that their sum will nearly vanish, as has been already remarked. As this circumstance depends on a theorem of some importance, which will furnish a valuable check on the developments we shall presently give, it is worth while to trace it to its origin. The elements of a planet depend on its position and its velocity at a given epoch ; each element is a function of the co-ordinates, their differential coefficients, and the time, or, representing an element by a, and putting, for shortness, t dx _ dy „ dz t-dt^-di^-dt' we have six equations of the form an=f(x,y, z, £, >?, £, f) (12) When we express the co-ordinates as a function of the elements and the time, we have x, y, or z —f (al} a.2, a3, a4, a6, ae, f) (13) Substituting for the elements the values just given, £, y, and £ must vanish iden- tically in the value of each co-ordinate. If, now, the changes in £, >y, and ^ are of a higher order of magnitude than those in x, y, and z, the co-ordinates will he subject to smaller variations than the elements. Suppose, now, that one of the co-ordinates is affected with an inequality of which the period is very short compared with that of the revolution of the planet. Represent it by c sin (pnt -f- e ) . Its differential coefficient will be pnccos THE 0 KBIT OF NEPTUNE. 15 Since the elements contain this coefficient, and therefore include terms in which the large number p multiplies the coefficient of the angle, their perturbations will be much larger than that of the co-ordinate. But, in passing from the perturb- ations of the elements to those of the co-ordinates, these large terms must destroy each other. Let us apply this principle to the case under consideration. That portion of the perturbative function which arises from the action of an inner planet on the Sun may be developed in a series of terms of the form * t (X c representing a number, not a line. It therefore becomes infinite when a is infinitely small. The second differential coefficient of the perturbation of any rectilineal co- ordinate of the outer planet will be of the order of magnitude . dR me -j-f — -r cos ^> da' a- putting N= iT + & + G. Q If we integrate this differential, and develop the quantity ., . according to i n ~\~ in 7? o the powers of — =. ~, the largest terms in the first differential coefficient of the (I,', n a'* co-ordinates will be of the form me . — sm 2V. This also will become infinite when a is infinitely small; and since the perturb- ations of the elements contain these terms, it follows that they also will be infinite in this case. Finally, by another integration, we shall have for the largest per- turbations of the co-ordinate itself men -^j- cos N, which will vanish when a is infinitely small. Hence, in the case under consider- ation, although the perturbations of tlie elements become infinite, those of the co-ordi- nates vanish. The co-ordinates referred to arc linear. The order of magnitude of the angular co-ordinates, or the logarithms of any linear co-ordinate, will be given by dividing by a'. We shall, therefore, have for largest term in the perturbations 8v, $3, or & log r =. mca N. cos Hence, when we collect the perturbations of the co-ordinates due to the cause in question, all terms of a higher order of magnitude than this ought to destroy each other identically. 16 THE ORBIT OF NEPTUNE § 10. That portion of the perturbative function which is due to the action of the inner planet on the sun is r' -5 cos V r V being the angular distance between the planets. Developing it in a series of terms of the form • cos (m + \JL f* h will be of the form -# c being a numerical coefficient, multiplied by powers of GC- the eccentricities and mutual inclinations. From this development, and the equations (3), (4), (5), (7), and (8), I have computed the following analytical values of the coefficients for the perturbations of the longitude, latitude, and logarithm of radius vector. a Vft :^ 25 a 6 ^32— (17) 2 Vu — 3 =e = e2 (— \l v, + V ^9 — THE OR13IT OF NEPTUNE. 17 = net (— = ue( 2 The values of JVW are as follows : N<» = X — K = - a,' + 2 A — o — 2 a/ — a — ' —a' — vf (19) ^ — 2/1' — 2/1 — — 2 —2 6> zz 3 (20) A'+ 2^— 2 o' — 4/1' — /L — 3o>' From these values of N the corresponding values of v are derived, remembering that ri ~ ' i' and i being the coefficients of /I' and 2. respectively in the value of N. The check on the correctness of the preceding values of V, R, and B may now n be applied by developing v in powers of — , and retaining only the first term ; /& that is, by putting v z= ^, v2 =. 0. Making these substitutions, all the values of % V, R, and B will be found to vanish. In other words, [j? will be the lowest power of /j. which will enter into the values of V, R, or B, as we have already shown from a priori considerations. For convenience, we shall give the values of V, R, and B developed according to the powers of n, the ratio of the mean motion's, a form similar to that in which the lunar inequalities are developed in the theory of the moon. Putting we have sy— May, 1865. 18 THE ORBIT OF NEPTUNE. We shall also put V rV V — — — yi-a*-ff _R _cR ^-a3-^' B cB c being a constant, equal to unity if we neglect the change of mean distance pro- duced by the action of other planets. We then have ! sin N, 8 log r = mac^R^ cos N, (21) sin N. Substituting the above developments for the vs in V, R, and B, we have Vf» = (1 — uz — i-e2) (— 1 —i? — 6 fj.s — 19 ft4) + ^(1 — 2(j.2 — 30p8) VV =€€>(- |- f;U2- \lt?) i^2+ fl«3+ f|M4) 1«2+ V3+ 25^) 3^2— 27 ^3 — 135 ^4) (22) _ ^ (_ y _ y ^ _ 2| 25 _l_42 — 24 =^ ( I— 6^2— 3(V — 116 ^4) (23) zre2 ( fTV^2- i1^3) THE ORBIT OF NEPTUNE. 19 Such arc the formula} by which we shall proceed to compute the perturbations of Neptune by Jupiter, Saturn, and Uranus. It will be noticed that the coefficient of ft vanishes identically in the last de- velopments. I have not completely investigated this law, but it seems to arise from the circumstance that that portion of the perturbation in question which proceeds from the change in the origin of co-ordinates is independent of (i, while that portion which is caused by the modified attraction of the Sun is of the order of magnitude ^. It furnishes a yet more valuable check than the last on the developments. § 11. Allusion has already been made to the complications introduced into the theory of Neptune by the near approach of its mean motion to double that of Uranus, and the consequent oscillation of all the elements of its orbit in a cycle of 4300 years of duration. In order to construct a dynamical theory which should be correct within a tenth of a second through the whole of one of these cycles, it would be necessary to include many terms dependent on the second, and perhaps some dependent on the third power of the masses of the disturbing planets. If this task were accomplished, the necessary uncertainty in the mass of Uranus and the elements of Neptune would destroy all the value of the theory. A change of one-tenth in the mass of Uranus would produce a change of 200" in the co- efficient of the perturbation of the mean longitude. The mean motions of Walker and Kowalski being each about 8" in error, the place of the planet from this cause alone would be in error by nearly 10° at the end of a cycle. After much careful consideration of different ways of relieving the theories of Uranus and Neptune from the complexities introduced by the large perturbations referred to, I finally determined to develop them not as perturbations of the co- ordinates, but of the elements. It will readily be seen that if the eccentricity or perihelion is greater than the mean during several revolutions of the planet, there will be a perturbation in the radius vector and longitude having nearly the same period with the revolution of the planet, although the latter may really scarcely wander from a true elliptic orbit during an entire revolution. In such a case it is clearly best, in constructing a theory designed to remain of the highest degree of exactness for only a few centuries, to take not the mean values of the elements, but their values at a particular epoch during the time the theory is expected to be used. In doing this, we shall be treating the change in the elements in the same way that the secular variations are usually treated. These variations are really periodic, and in a perfect theory would have to be treated as such. But the elliptic elements on which all our planetary theories are founded are not mean elements, but elements brought up by secular variation to the epoch 1800 or 1850. Thus, our perturbations of the elements will be of the form 01 IT Sa zz c -f aj + 2a2 {kt-^-s}, cos iji which a' is the secular variation proper, k a small coefficient equal to 2 ri — n or its multiples, and c a constant added to the integral, of such value as to make &a vanish at the epoch 1850. 20 THE ORBIT OP NEPTUNE. § 12. Adopted dements and masses. The elements of Neptune adopted in the computation of the perturbations are obtained by correcting those of Walker so as to agree with the Lalande obser- vations, and as nearly as possible with seven normal places derived from the modern observations from 1846 to 18G3. The latter series is thus represented within a second of arc. As these elements are merely provisional, it is not worth while to give any details of the corrections, except their amounts, which are as follows : &« = — 4° 11' 18".6 ; n = 43° 3' 18".G be = — .00025451; e =.00846495 &n = — 8".40G ; n = 7864".3G8 & - _ 3' 5".92 ; e = 335 5 31.10 log a = 1.4 780405 i 1° 47' 1" n 130 7 20 Epoch, Jan. 0, 1850, Greenwich, M. noon. To obtain the value of log a, the mean motion was diminished by the secular variation of the longitude of the epoch = 21".354. A more exact value of this quantity will appear, in the course of our computations, to be 21".4426. The provisional inclination and longitude have been taken from Walker without change, as the small corrections which his values of these elements may require will not affect the perturbations. The adopted elements of Uranus, Saturn, and Jupiter, with their functions used in the theory for the same epoch, are as follows : Uranus. Saturn. Jupiter. 71 167° 34' 21" 90° 4' 0" 11° 54' 51" £ 28 27 14 14 48 40 159 50 20 i 0 46 30 2 29 28.8 1 18 41.1 0 73 14 14 112 22 14 98 56 10 n 15425.030 43996.127 109256.72 e — .0466972 .0560050 .0482273 log a 1.2837047 0.9802225 0.7162201 t 335°38' 77°56' 355°52' u .0131517 .0083880 .0082735 a 0.638195 0.317301 0.1727703 m t i i These elements of Uranus have been obtained by applying to Feircc's values of the mean elements (Appendix to American Ephemeris and Nautical Almanac, 1860-64, p. 4) approximate long-period perturbations of the elements produced by Neptune at the epoch 1850. The elements of Jupiter and Saturn are from Hanson's prize memoir on the mutual perturbations of those planets, and are, sub- stantially, the same as Bouvard's. THE ORBIT OF NEPTUNE. 21 The values of those constants which depend on the ratio of the mean distances are as follows, using the notation of the Mecanique Celeste : L— URANUS AND NEPTUNE. c/i(; rf^T «s i d«K d'V? I Bi Jo, ' da* 1 da* da* 0 2.26969 0.72903 1.8326 6.4384 35.17 1 -1.68379 6.05279 —13.0023 65.5556 —259.42 2 0.37751 0.95867 2.1283 6.7135 35.99 3 0.20310 0.72530 2.2389 7.4924 36.95 4 0.11422 0.52446 2.1024 8.2270 39.52 5 0.06593 0.36954 1.8319 8.5192 43.00 G 0.03870 0.25606 1.5157 8.302 46.01 7 0.02299 0.17533 1.2085 7.679 47.57 8 0.01379 0.11900 0.9365 6.804 47.27 9 0.00832 0.0802 0.7100 5.818 45.18 10 0.0051 0.054 0.533 j<0 "**l "^ da" 0.8966 26.5493 2.80 3.2907 11.9366 60.92 2.4710 11.0760 59.76 1.7806 9.6115 57.07 1.2524 7.9427 52.59 0.8668 6.3301 46.80 0.5931 4.9065 40.34 0.4023 3.7215 33.83 0.2711 2.7738 27.69 0.1817 2.0381 22.20 0 1 2 , 3 4 5 6 7 8 9 It will be observed that in 5|, atff, and their differential coefficients, we have included those multiples of — which are introduced by the action of Uranus on the Sun. It seemed less laborious to do this than to make, a separate computation of the terms produced by this cause. But for Saturn and Jupiter —^ is so large that it will be better to use the developments previously given. oc 22 THE ORBIT OF NEPTUNE. II.— SATURN AND NEPTUNE. i • ;; (i) •3 rffS 3'raT / of decimals, to avoid writing zeros. The logarithms are reduced to the common base, 10, .and are expressed in units of the seventh place. THE ORBIT OF NEPTUNE. 23 ACTION OP URANUS. I. — / iz: 0 ; /' ~ 0 tt 7 »/ I = 0. ^, 0 + 1 2 3 4 5 6 7 8 9 » 0 — 1 — 2 — 3 — 4 -6 — 6 — 7 — 8 — 9 A + 1135.50 840.31 + 187.98 + 100.3 7 + 55.83 + 31.75 + 18.29 + 10.63 + 6 2 +3.7 a.Dai l + 367.47 + 3026.10 + 478.7 + 359.3 + 256.9 + 178.5 + 121.4 + 81.2 + 53 6 +36 Mh + 6 Hi; 4 r. .52 — 4.1 — 7.6 — 8.7 — 8.4 — 7 4 -6.2 — 5 0 -4 IDuh. — 10.84 — 2.66 — 8.36 — 6.1 — 4.3 — 3.0 — 2.1 — 1.4 — 1 0 • L + 3005.97 + 1747.45 + 1919.99 + 1232.4 + 799.6 + 519.5 + 336.3 + 216.9 + 138 9 +91 tf W 6 ;«; -t 1S 53 — 4.1 — 7.6 — 8.7 -8.4 — 7 t -6.2 — 6 i E 0 + 3.56 — 1.0 — 1.3 — 0.9 — 0.7 — 0.5 — 0.3 — 0 2 it // tt it n tt tt tt „ J!-i-sin JV — 17.853 — 9.808 — 4.19 7 —2.043 -1.061 — 0.672 — 0.317 — 0.17 8 —0.102 6u-t-sin (N — f} 4 0.( ia — 0.112 — 0.06 6 — O.OS2 -0.028 — 0.0 IK — 0.012 — 0.00 8 N h jf O.I (HI — 0.096 — 0.05 J —0.037 -0.025 -0.0 17 — 0.011 — 0.00 8 N + 0.( KK> — 0.001 — 0.00 1 N+if —0.001 — 0.001 — 0.00 1 6 log r -f- cos N + 361 — 81 — 43 :-24 14 — 8 — 5 — 3 -r2 N-j e 0 — 1 — 1 0 0 0 0 0 0 N+f 0 + 1 + 1 0 0 0 0 0 0 S/3 -s- sin (.2V— F) — 0.030 + 0.055 + 0.02 3 + 0.014 + 0.008 + 0.005 + 0.003 + 0.00 1 (Ar+ r) + 0.083 + 0.030 + 0.01 1 + 0.007 + 0.004 + 0.002 + 0.001 + 0.00 n.-y=i;/ = - L; , = o. i' — 7 6 6 — 4 —3 — 2 —1 0 + 1 2 3 4 6 6 7 t + 7 6 6 4 3 2 1 0 —2 — 3 1 — 5 — 6 — 7 /i + 0.21 + 0.26 + 0.30 + 0.33 +0.3 2 +0.24 + 0.05 — 0.24 — 0.32 0.91 + 0.35 + 0.' 18 +0.50 + 0.4€ + 0.40 a.Dah + 1.8 + 1.9 + 1.9 + 1.65 +1.1 6 +0.38 — 0.66 — 1.32 -1.50 + 1.05 + 0.20 + 1.: 4 +2.00 + 2.37 + 2.5 De'll + 24.8 : .".( 5 + 35 .1 + 38.5 +37.4 + 27.93 + 5.69 — 28 .77 — -38.29 — 1 J7.13 + 40.77 + 66.1 + 58.0 + 53.0 + 44.6 L e'W + 4.8 + 24.8 +5.2 + 30.5 + 5.4 + 35.1 + 5.1 + 4.1 + 38.5 +37.4 + 2.10 + 27.93 — 0.82 + 5.69 — 2.24 — 28.77 - -4.80 -38.29 — 3.01 — 107.13 + 2.4 + 40.77 + 5.1 + 56.1 + 6.8 + 68.0 + 7.3 + 53.0 + 7.2 + 44.5 E + 24.6 + 30.3 + 34.9 + 38.3 + 37.2 + 27.81 + 6.65 — 28.95- -38.47 — 107.20 + 40.61 + 55.E + 67.6 + 52.4 + 43.7 n / r , t tt n tt tf „ it it „ n n it &l -f- sin N + 0.007 + 0.009 + 0.011 + 0.013 + 0.01 4 + 0.011 — 0.008 4 •0.049 + 0.015 — 0.008 — 0.01 3—0.014 — 0.012 — 0.010 «D-^sin(JV— /) — 0.072 — 0.103 — 0.143 — 0.196—0.25 5—0.284 — 0.115 -0.783 — 1.095 + 0.277 6 + 0.236 + 0.179 + 0.130 N — 2J — 0.001 — 0.001 — 0.002 — 0.002—0.00 3—0.003 — 0.001 -0.008 — 0.012 + 0.003 + O.OC 8 + 0.002 + 0.002 + 0.001 & + f — 0.002 -1 0.002 J log r ^ cos N— f — 1 — 1 — 1 — 2 —3 — 3 — 1 — 8 ll + 3 + 3 + 2 + 2 + 1 Ill.-j=-l;j' = 0; , = 0 i' — 5 _4 — 3 — 2 — 1 0 + 1 2 3 . 4 5 6 7 8 i + 6 5 4 3 2 1 0 — 1 2 — 3 — 4 — 6 — 6 — 7 h + 6.5 + 9.0 + 11.4 + 12. r —219.7 — 17.00 — 62.71 57.57 3 —46.20 — 33.2- 23.66 — 16.41 — 11.20 — 7.6 af)ah -t 34.1 4 36.0 + 32.1 H 17. t +444.1 — 59.5 - - 120.65 — 1 r,i.f>7 — 170.23 — IS 7.H — 1 35.8 - -110.3 — 86.4 — 66.2 De'h — 2.0 — 1.7 — 1.3 — 1. ) + 1.01 — 1.50 — 1.29 + 0.61 + 2.96 + 4.81 ) +6.0 + 6.4 + 6.2 + 5.7 IDuh 0 0 0 + 0. i + 2.75 + 2.31 + 3.23 • - 3.61 + 3.48 + 3.01 ) - -2.6 + 2.2 + 1.4 + 1.2 L -f 95.5 + 10R.6 + 108.7 4 7;>. S +223.3 — 153.0 - - 178.40 + 85 IIC..7- — 871.70 — 6S 4.2 — < 43.5 - -331.0 - -244.5 — 180 e'W — 2.0 — 1.7 — 1.3 — 1. ) + 1.01 — 1.50 — 1.29 + 0.61 + 2.96 + 4.8 > +6.0 + 6.4 + 6.2 + 6.7 E + 0.1 + 0.2 + 0.2 + 0. L —0.95 0.00 + 0.27 + 0.48 + 0.67 ' + 0.5( i +0.5 + 0.4 + 0.3 + O.S n n „ „ „ „ n „ tt „ it if SI -t- sin 2V + 0.138 + 0.184 + 0.220 + 0.201 i +0.750 — 0.766 — 1.752 + 2163.60 5 +9.279 + 3.09! + 1.631 + 0.854 + 0.504 + 0.308 n ff v — sin fJV f) + 0.004 + 0.004 + 0.004 + 0.005 + 0.004 + 0.005 + 0.00. + 0.00. 1 +0.006 > 0 + 0.001 + 0.001 — 0.005 0 + 0.116 + 0.104 + 0.054 + 0.04S + 0.036 + 0.032 + 0.025 + 0.022 + 0.018 + 0.0161 + o.oi n + 0.012 i log r -f- cos If — 2 — 2 — 3 — 3 + 31 0 — 26 + 61 + 29 + 17 + 11 + 6 + 4 (^V — /") + 1 1 <^+y) — 1 — 1 ^.^yr-r) 0 0 0 + 0.00. + 0.004 + 0.012 + 0.036 — 0.046 — 0.021 — 0.011 — 0.007 • -0.004 - o.oor sin(JV+ F) + 0.001 + 0.014 + 0.012 + 0.028 — 0.028 — 0.011 — 0.006 — 0.004 - -0.002 -0.001 _ 24 THE ORBIT OF NEPTUNE. IV.- -j = 0;j' = — 1; i = 0. *' —5 • +6 — 4 S — 3 4 — 2 3 — 1 2 0 1 1 0 2 — 1 3 1 4 — 3 5 — 4 6 — 5 7 — 6 8 9 -7 —8 ft —0.68 aDaJl —4.17 Vf'h —79.9 I H'ik 0 i —11.5 J5 —80.1 —0.91 — 4.56 — 107.5 0 — 13.2 — 107.5 — 1.1.' — 4.2;: — 133.8 0 — 13.5 — 133.9 — 1.21 — 2.71 — 142.5 — 0.1 — 10.3 — 142.6 — 0.72 --- 11.97 -85.17 + — 0.16 —0.62 -85.24 + + 32.76 — 54.83 38fi5.es — 0.52 — 27.80 3865.40 + 12.73 + 14.12 + 1503.24 — 0.51 + 21.87 + 1502.86 + 4.267 + 47.61 + 504.23 — 0.611 -557.07 + 504.02 + 12.016 + 33.38 + 1418.28 — 0.72 + 214.18 + 1418.32 + 9.00 :. :\:;.su r 1061.5 — 0.68 + 147.4 + 1061.7 + 6.43 + 30.55 + 758.9 - — 0.6 + 111.0 + 759.4 - + 4.47 + 25.64 t- 527.1 — 0.5 + 83.6 h 527.7 + 3.04 + + 20.5 + + 358.7 + 2 — 0.4 — + 62.0 + f 359.3 + 2- 2.05 + 1.36 15.8 + 11.8 40.1 + 158.8 0.3 0 15.3 + 32.1 10.7 +159.4 // / n tt it n n n • 5( -r- sin ,2V —0.017 jo^siu(JV— /) +0.232 Jf—2f +0.002 N— 3/ 0 A> / 0 — 0.022 + 0.364 + 0.004 0 0 — 0.027 + 0.543 + 0.006 0 0 — 0.026 + 0.721 + 0.008 0 0 -0.002 l n..-,::] - + 0.006 0 0 — 0.139 -38.716 — 0.411 — 0.006 — 0.002 + 0.215 — 29.524 — 0.313 — O.IXB — 0.001 - 141.69 — 2.279 + 30.174 + 0.321 + 0.004 — 0.011 — 0.770 + 11.061 + 0.117 + 0.001 — 0.008 — 0.383 + 5.239 + 0.055 + 0.001 — 0.005 — 0.216 + 2.720 + 0.029 0 — 0.003 — 0.128 — ( + 1.478 +( + 0.016 +( 0 I — 0.002 — ( (.077 —0.040 ).823 +0.467 1.009 +0.005 ) 0 1.002 —0.001 03 jr— 2/ o 0 0 0 0 + 8 0 0 + « 0 + 2 — 408 — 5 + 6 — 311 — 4 — 17 + 318 + 4 — 8 + 116 + 1 — 5 + 55 + 1 — *\ + 29 0 — 2 — + 15 + 0 1 0 9 +6 0 0 tt ii tt „ „ ,i 5|3-^siiifjV + T) 0 0 0 0 0 0 0 0 0 — 0.003 — 0.003 — 0.005 — 0.005 — 0.005 — 0.010 — 0.002 — 0.005 — 0.001 — 0.003 — 0.001 — 0.002 0 — 0.001 0 0 0 0 y._/--2j/=lit=:0. i' i — 4 5 — 3 4 -2 3 —1 2 0 1 1 0 2 — 1 3 — 2 4 — 3 5 — 4 6 — 5 7 — 6 8 — 7 A a Pa/i 2ZVA + 0.03 +0.02 + 0.1 + 0.0 + 6.5 + 4.6 — 0.0 + 0.2 — 15.9 J +0.01 0.0 + 1.4 + 0.02 + 0.08 + 6.1 + 0.006 + 0.08 + 1.3 — 0.0145 + 0.014 — 3.87 — 0.033 — 0.11 — 7.9 — 0.0 — 0.2, — 11.0 6 —0.05 — 0.34 — 13.0 5 —0.06 — 0.40 — 13 — 0.05 — 0.44 — 12 — 0.05 — 0.44 — 11 „ n a H it n • n „ it {I -f- sin JV + 0.001 0 «r-i-8in(Ar+/)— 0.011 —0.009 0 + 0.04 0 J— 0.005 + 0.001 — 0.026 + 0.002 — 0.013 + 0.56 + 0.007 — 0.084 + O.W — 0.0, 5 +0.00 7 —0.04 4 +0.003 4 —0.032 + 0.00' — 0.02- >. +0.002 — 0.019 vi._ y sliis-iMSst t' t — 4 + 5 — 3 4 — 2 — 1 3 2 0 1 1 0 2 — 1 3456 _2 —3 —4 —5 7 — 6 8 — 7 & 2ZVA — .002 — 1.0 — .002 — 0.9 — .001 — M -0.7 —0.6! 1 — .002 — 1.04 — .004 — 2.10 — .0058 — 2.80 — .007 +.008 +.012 +.01 — 3.47 +2.86 +6.9 +7.8 i +.018 + 8.6 + .018 + 8.8 tt tt II 0 ti 0 n 0 0 0 0 | + 0.21 — 0.001 000 // n n n 0^ 0 it S«-i-Bin(JV— /) + 0.002 + 0.002 + 0.002 +o.a 12 +0.005 + 0.021 — 0.037 +0.015 +0.020 +0.02) ) + 0.017 + 0.015 VII.— y=l;y = 0; t = -2 i — 4 + 5 - 3 4 — 2 — 3 1 0 2 1 1 0 2 1 3 2 456 -3 —4 —5 7 — 6 8 — 7 h IDu A — 1.3 -1.7 — 1.9 —2. 2 —23 — 1.85 — 0.031 — 1.17 — 0.66 —0.3 —0.1 0 0 0 «( +- sin JV • + 1.11 n „ tt it it „ / ,, ti 83 -5- sin 0 vr-F) — 0.004- -o.oo- — 0.010 — 0 015 —0.02! — 0.03 6—0.58 + 0.007 +0.002 0 0 0 0 . THK ORBIT OF NEPTUNE. 25 VIIL— y=0;/ = l; 6 = — 2 t i + 4 + 5 3 4 — 2 3 — 1 2 0 1 1 0 2 — 1 3 — 2 4 — C 5 — 4 6 — 5 7 — 6 IDe'h + 1.6 + 1.8 + 1.8 + 1.6 + 2.3 + 0.4 - t-0.10 — 0.09 — 0.1 B —0.21 — 0.17 — 0.14 IDu/t + 0.5 + 0.6 + 0.6 + 0.5 + 0.75 + 0.15 - -0.033 — 0.03 — 0.0 3 —0.06 — 0.04 0 „ n it it it it n tt it ar-i-si l(AT+/ — O.OC 13 —0.004 — 0.005 — 0.005 — 0.012 — 0.004 — 0.001 — 0.0 01 —0.00 1 0 0 „ „ n // it tt 20-!- sin (A*— I") + 0.0( 1 +0.001 + 0.002 + 0.002 + 0.004 + 0.001 0 0 0 0 0 ix.— y =_*;/=o;t=b. i' — 3 _., — 1 0 i 2 3 4 5 0 7 8 9 t — 5 4 3 2 i 0 — 1 — 2 — 3 — 4 — 5 — 6 — 1 h Dt'lt + 0.66 + 2.07 — 0.06 + 0.64 + 1.36 — 0.01 — 17.57 + 30.S + 0.19 + 0.10 + 1.36 : 0.07 + 0.214 + 5.03 + 0.12 + 2.766 +9.55 + 0.06 + 3.750 + 15.48 — 0.17 + 3.944 + 19.71 — 0.51 + 3.660 + 21.67 — 0.86 + 3.161 + 21.6 — 1.15 + 2.58 + 20.2 — 1.35 + 2.04 4 18.0 - — 1.4 + 1.57 H5.4 — 1.4 L + 6.4 + 4.7 + 33.- + 2.9 + 10.3 + 16.3 + 5.32 — 565.6 + 112.77 + 80.22 + 64.9 453.1 - H41.9 „ n t. n n n „ ff * • // it // SI -r- sin JV + 0.009 + 0.008 + 0.068 + 0.007 + 0.034 + 0.080 + 0.050 — 71.93 — 1.253 —0.425 — 0.227 - -0.138 - -0.087 2i>-rin(V— /• 0 0 0 0 0 0 + 0.002 0 0.021 — 0.010 — 0.007 - -0.005 - -0.003 (A- + / 0 0 0 0 0 0 + 0.001 0 0.018 — 0.009 — 0.007 • -0.005 - -0.003 •TT1 • 1 . ^ — "I {, -I -2 — 1 0 1 2 3 4 5 6 7 8 9 i h5 4 3 2 1 0 — 1 — 2 — 3 ^— 4 — 5 — 6 — 7 h 0.113 — 0.107 - -0.0!K) + 2.814 — 0.325 — 1.305 — 1.90 3 —2.06 — 1.954 — 1.70 0 —1.4 0 — 1. 2 —0.86 a Hah 0.50 — 0 42 - -0.40 - 6.48 — 1 .50 — 3.38 — 6.03 — i.30 -9.63 — 10.01 — 9.1 2 —8. •4 — 7.5* He'lt — 3.3 — •i 5 — 10.5 H ; .".1.8 -38J) — 154.2 — 224.07 — 24. 1.19 — 2 28.57 — 197.7 — 161 .t — 127. ! —96.9 L 1.4 — i 2 -1.1 -3.5 — 6.11 — 0.38 42! — 57 .2!t — 40.86 — 33.2 — 27. I —22.3 K — 3.3 —12.5 — 10.5 + 331.8 -38.7 — 154.2 — 224.05 — 243.20 — 228.68 — 197.8 — 161.S — 127. ) —97.0 „ H „ „ n it „ „ „ * // // n SI -f- sin A" — 0.002 —0.002 - -0.0112 — 0.015 — 0.011 — 0.03C — 0.00 ! +38.09 + 0.63C + 0.21 7 +0.11 6 +0.01 55 + 0.04i ai'-s-ninr.V— /) + (-V-2/I 0.038 + 0.0 12 4 0 0 -0.012 0 — 1 .lift! — 0.017 + 0.257 + 0.003 + 1.514 + o.oie + 4.25 + 0.04 0 5 — 5.074 — 0.054 — 2.10 — 0.02 2 —l.K 2 —0.01 1 —0.61 2 —0.01 •A— 0.402 17 — 0.004 5 log r -^ cos A7 0 0 0 0 0 0 — 2 + 5 + 2 + 1 + 1 0 (A'-/) 0 0 0 — 17 4-3 + 16 + 44 — 53 — 22 — 12 — 7 — 4 XI -/=0;/=-i i' — 3 — 2 0 l 2 3 4 5 6 7 8 9 t 45 4 3 2 i 0 — 1 — 2 — 3 —4 — 6 — 6 — 7 A a.Da.h 0 + .03 0 + .03 0 + .03 + .01 t-o.oc + 0.01 + 0.18 + 0.14 + 0.25 + 0.169 + 0.655 + 0.2677 + 0.810 + 0.259 + 1.018 + 0.228 + 1.12 + 0.206 + 1.11 + 0.152 + 1.04 + 0.118 + 0.92 De'lt L E + 1.1 + 1.1 + 1.1 + 1.1 + 1.1 + 1.1 + 2.08 + 2.1 + 1.76 + 0.4 + 1.8 + 32.51 + 0.50 + 32.50 + 40.15 + 0.36 + 40.15 + 63.13 — 39.2 + 63.13 + 60 52 4 + 7.24 + 60.54 4 52.90 4 + 5.15 - 52.92 4 - 42.98 + 4.4 - 43.01 1- 34.1 + 3.5 t-34.1 + 25.8 + 2.2 + 25.8 „ ti tt / „ n it n n S! -i- sill N 0 0 0 0 + 0.001 + 0.002 + 0.003 — 4< 19 — 0.080 -0.027 -0.015 — 0.009 — 0.005 „ n „ it n „ n a n n n So-f-sinOV— f UV-2/ ) —0.003 ) 0 — 0.00 0 4 —0.004 0 — 0.010 0 — 0.012 0 — 0.319 — 0.003 — 0.757 — 0.008 + 1.344 + 0.014 + 0.564 + 0.006 + 0.301 + 0.003 + 0.178 + 0.002 + 0.110 + 0.001 2 logr -j- cos (A' — f) 0 0 0 0 0 — 3 — 8 + 15 + 6 + 4 + 2 + 1 Hay, 1865. 26 THE ORBIT OF NEPTUNE. xn.-,-=-3;y=o. \ 6 — 3 L + 51.5 « + -»* + 4.37 XIII.-/ = — 2; $- — 1. 5 0 + 3 1 2 2 1 3 0 4 — 1 5 — 2 6 — 3 7 — 4 8 — 5 9 — 6 10 II1.1 7 £ 2iVA + 64.5 + 1.4 + 6.0 + 23.4 + 41.7 + 55.17 — 38.5 — 3.26 + 62.63 + 68.87 + 53.4 + 44.8 rr rr „ rr rr „ rr rr rr /, ° N—Zf — 0.091 — 0.003 — 0.015 — 0.076 — 0.001 — 0.201 — 0.002 — 0.503 — 0.005 + 0.727 + 0.008 + 0.320 + 0.003 + 0.189 + 0.002 + 0.116 + 0.001 XIV.-/ = -l;/ = -2. i' 1 0 + 3 1 2 2 1 3 0 4 — 1 5 — 2 6 — 3 7 — 4 8 — 5 9 — 6 10 — 7 £ 2/Vft — 03 — 1.8 — 2.8 — 10.9 — 20.7 — 28.4 + 10.0 rr — 3330 — 31.7 — 28.5 — 24.8 rr rr rr rr rr + 0.85 rr rr „ rr 8r -h sin (N—f) 0 + 0.004 + 0.007 + 0.036 + 0.100 + 0.259 + 0.387 + 0.172 + 0.101 — 0.065 XV.^=0;/ = _3. 5 0 + 3 1 2 2 1 3 0 4 — 1 5 — 2 6 — 3 7 — 4 8 — 5 9 — 6 10 — 7 2fle'ft 0 + 0.1 + 03 + 1.2 + 2.3 + 3.6 + 4.25 + 4.47 + 4.24 + 3.8 + 3.3 rr rr „ „ rr rr rr rr •. + -«(*-/> 0 0 — 0.001 — 0.004 — 0.011 — 0.033 + 0.052 + 0.023 + 0.013 + 0.009 THE OKBIT OP NEPTUNE. 27 ACTION OF SATURN. if 0 1 2 3 4 i 0 — 1 — 2 — 3 4 h aDah De'h \Duh L E + 1026.84 + 57.04 + 0.780 — 0.773 + 2167.76 0 + 164.82 + 178.60 — 1.092 — 0.99 + 794.46 — 0.70 + 39.15 + 82.47 — 1.56 — 0.44 + 268.80 — 0.33 + 10.3 + 32.3 — 1.02 — 0.17 + 91.9 — 0.1 + 2.8 + 11.9 — 0.5 — 0.06 + 31.2 — 0.1 SI -H sin N- — 10.186 — 1.723 — 0.394 — 0.100 -=- sin (# — /) — 0.007 — 0092 + 0.180 + 0033 + 0.008 30 THE ORBIT OF NEPTUNE. XII.-^ = — !;/ = — 2. ¥ i + 2 + 1 3 0 4 — 1 5 — 2 6 — 3 De'k — 0.14 — 1.75 — 2.00 — 1.5 — 1.0 // ir it i> if «v^a\n(N—f) + 0.001 + 0.068 — 0.148 — 0.028 — 0.010 XIIL— y=0;/ = — 3. i' i + 2 + 1 3 0 4 — 1 6 — 2 . 6 — 3 De'h + 0.02 + 0.28 + 0.40 + 0.30 + 0.3 ft rf // // ti iv-~ sin (AT—/) 0 — 0.011 + 0.030 + 0.006 + 0.003 THE ORBIT OP NEPTUNE. 31 ACTION OF JUPITER. The direct action of Jupiter is so nearly insignificant that the details of the computation are omitted. The only terms in the longitude exceeding one hun- dredth of a second, and not sensibly confounded with the elliptic elements of Neptune, are 0".278sin (% — X) + 0 .019 sin 2 (tf — A ACTION. OF VENUS, EARTH, AND MARS. The only appreciable effect of the attraction of these planets is found in the relation between the radius vector and the mean motion. The coefficients of the perturbative function which correspond to the case when both i' and i are zero introduce changes as below into the secular variation of the longitude of the epoch. Those which correspond to the term in which N=X — o' introduce con- stants as below into the logarithm of the radius vector. For the sake of com- pleteness we include the similar perturbations produced by Jupiter, Saturn, and Uranus, as already computed : de It Action of Venus, + 0".0403 — 11 Earth, + 0 .0444 — 12 Mars, + 0 .0059 — 2 Jupiter, +15.3571 —4240 Saturn, +4.8687 —1344 Uranus, + 1 .1261 —311 Total, 21.4425 — 5920 The principal term of y , and, indeed, the entire portion not multiplied by the at second power of the eccentricity, is while the principal term in 8 log r is 8 lo r = — The effect of these terms might, therefore, have been included in the mean distance as a single term, without appreciable error. § 14. Perturbations of Neptune l>y Saturn throuyh the Sun. These perturbations, it will be remembered, have been omitted in the preceding computations, from reasons already set forth. They have been computed by formula) (16) — (19), and are as follows: 32 THE ORBIT OF NEPTUNE. - 20".536 sin (X — X) 0.007 sin (2 a/— 2 ;i — o' + + 0.530 sin (— a' + 2 a — o) — 0 .059 sin (A, -co') — 0 .340 sin (2 X — a — o') + 0 .022 sin (— 51' + 3 a — 2 o . 0 .007 sin (A/ + a — 2 u) — 0 .002 sin (2 a, — o — o') ACTION OF SATURN. 8 log r = + 345 cos (a/ — + 10 cos (— 3,'+ 2 A — w) — 2 cos (* — o') + 3 cos (2 a' — a, — o') § 15. Perturbations of the elements. — Collecting and adding up the coefficients of all sines or cosines of the same angle in the perturbations, \ve find them as below. For 2, and a, their values, I — t and -n — t, are substituted. We shall first collect those terms which are developed as perturbations of the elements, namely, the secular variations, and all terms in the action of Uranus in which i' — 2 i. We find them to be as follows : + 125".67 sin (2 7' — 7) — 0.42sin (27' — I — 2n) -0.36 sin (2? — l+n — if) + 0.14sin (2 1 — I + Tt'— TI) — 30".93 sin (4 Z' — 2 7 — TI) + 8 .03 sin (4? — 27 — Tt7) • 0.03sin(47' — 27+7^ — 27t) + 2".62 sin (6 7' — 3 7 — 2 7t) — 1. 37 sin (62'— 37 — rt — n) + 0.17sin(67'— 37 — 2 71') + + + 2163".60sin(27' — 7 — TI) 14 1.69 sin (2 7' — 7— TI') 0.56 sin (27' — 7+ TT' — 2 ?t) 0.21 sin (27' — 7+7t — 27t/) 1 .08 sin (27' — 7 +71 —2 T) O.OSsin (27' — 7+Tt' — 2r) = + 125".G7 cos (2 ?' — 7) + 0 .42 cos (21' — I — 2 TT) —0.36 cos (27' — I — it + 71} + 0.14cos (27' — 7+ rf — n) — 30".93 cos (4 7' — 2 7 — n) + 8 .03 cos (4 7' — 2 7 — 7t') — 0 .03 cos (4 7' — 2 7+ it— 2*) + 2".62 cos (6 7' — 3 7 — 2 n) —1.37 cos (6 7' — 3 7 — Tt' — 7t) + 0 .17 cos (6 I — 37 — 2 TI') +0".003U a = — 1232 cos (2 7' — 7 — n) + 92 cos (2 7' — 7 — rf) + 85 cos (4 I' — 2 7 — 2 n) — 44 cos (4 7'— 27 — T^ — n) + 6 cos (4 7' — 2 7— 27^) — 71".93 sin (4 7' — 2 7 — 2 n) + 38 .09 sin (4 7' — 27 — TI' — 7t) — 4 .99 sin (4 7' — 27 — 2 7t') + 4".36sin (67'— 37— 3 TI) -3.27 sin (6 7' — 3 7 — Tt7 — 27t) + 0 .85 sin (G ¥ — 3 7 — 2 rt — n} — 0.08 sin (07'— 37— 3^) + 2V.4425 i THE ORBIT OF NEPTUNE. 33 = — rMlsin (2 f — I — 71+ T) — 0 .72 sin (2 P — I — « — T) + 0 .16 sin (2 I' — I — 71!+ r) + 0 .15 sin (2 ? — Z — TI'— T) — 2".98sin (4P — 2Z — T) 0".0110 « — l".ll cos (2 Z' — Z — n + T) + 0 .72 cos (2 P — I — n — T) + O.lGcos (2Z' — Z — 7t+ T) — 0 .15 cos (2 1' — I — rf— T) — 2".98cos(4Z' — 2Z — T) + 0".0001< § 16. Perturbations of the co-ordinates — Comparison with PEIRCE and KOWALSKI. — The first column of the following tables gives the coefficients according to Peirce (Proceedings of the American Academy, Vol. 1, pp. 287-291) ; and the second, the values according to Kowalski (Recherches sur les mouvements de Neptune, pp. 14-16). In the case of Uranus, Peirce's coefficients have been increased by £ + 3*5-* ^° reduce his mass of Uranus to the adopted one. The coefficients enclosed in parentheses are not comparable, as they include the effect of terms now developed as perturbations of the elements, and therefore omitted from the perturbations of the co-ordinates. The perturbations of the radiua vector have been reduced to logarithms by multiplying by I.— ACTION OF URANUS. c5 log r = -206".91) (_244".40) + 3' '.002 sin (I' — 1) (—2284) (— 2289) + 314 cos (I' — I) f 10 .24 + 10 .02 + 9 .994 sin 2 (f — I) + 167 + 163 + 162 cos 2 (I — I) f 2 .01 + 2 .02 + 1 .960 sin 3 (t — I) + 40 + 69 + 38 cos 3 (I — I) f 0 .64 + 0 .62 + 0 .610 sin 4 (V — I) + 14 + 38 + 18 cos 4 (P — I) f 0.25 + 0 .27 + 0 .237 sin 5 (V — I) + 5 + 23 + 5 cos 5 (V — /) f 0 .11 + 0 35 + 0 .104 sin 6 (J' — I) + 2 + 11 + 1 cos 6 (f — I) f 0 .05 + 0 .27 + 0 .041 sin 7 (I' — I) f 0 .02 + o .017 sin 8 (f — I) f 0 .01 + o .007 sin 9 (P — I) + 0".002 sin (— 4 V + 4 I — it" + it) + 0 .016 sin (— 3 1' + 3 I — it' + IT) (- 0.11) (- 0.73) — 0 .103 sin (— 2 f + 2 1 — it' + IT) (— 16.29) (— 16.79) — 0 .048 sin (— 1' + I — V + it) (+ 0.66) (+ 0.71) + 0 .045 sin ( 1'— l — ir' + it) Q .011 sin ( 2 1' — 2 I — it' + it) + 0 .003 sin ( 3 1' — 8 I — it1 + it) + 0 .003 sin ( 41' + 41 — IT" + it) + o .002 sin ( 5 1' + 5 I — it' + it) — 0.01 — 0".009 sin (— 5 1' + 6 1 — it) — 0.01 — 0 .014 sin (— 41' + 51 — ?r) — 0.02 — 0 .024 sin (— 3 f + 4 i — ir) — 0.04 — 0.08 — 0 .033 sin (— 2 /' + 3 1 — IT) + 0.19 + 0.19 + 0 .183 sin (— 1' + 2 I — it) + 2 + 2 + 3 cos (— V + 2 1 — it) + 0.27 — 1.31 + 0 .274 sin ( / — IT) 5 + 11 — 5 cos ( l-it) — 0 .238 sin ( /' — TT) — 10 cos ( V — it) (1979.72) (1955.50) + 4 .365 sin ( 21'— 1 — it) (— 1141) (-1127) + 43 cos ( 21' — I — it) (+69.86) (+68.73) + 9 .563 sin ( 31' — 21 — it) (+ 693) (+ 663) + 58 cos ( 3 1 — 21 — it) — 1.78 -1.78 — 1 .721 sin ( 41' — SI — it) 28 — 27 — 27 cos ( 41' — 31 — it) — 0.33 — 0.59 — 0 .375 sin ( 51' — 41 — it) 7 — 5 — 7 cos ( 61' — 41-it) — 0.12 — 0.29 — 0 .134 sin ( 61' — 51 — it) 3 — 1 — 2 cos ( 61' — 51 — it) — 0.06 — 0 .057 sin ( 7 V — 6 1 — ir) 2 — 2 cos ( 71' — 61— it) — 0.04 — 0 .022 sin ( 81'— 71 — a) _ 2cos( 81' — 71 — it) — 0-01 -0 .009 sin ( 9 1' — 8 / — ir) 5 May, 1865. 34 THE ORBIT OF NEPTUNE. ACTION OF URANUS (Continued). p. (-0.01) tv — K. N. + 0".001 sin (— 5 V + 6 1 — it1) + 0 .002 sin (— 4 V + 5 1 — it') — 0 .002 sin (— 3P + 4J — Tr1) — 0 .015sin(— 21' + 31 — it1) P. K. 6 log T = jr. + lcoa(— SI' + 4 1 — IT) — lcos(— 21' + 31 — it) (-0.11) — 0 .109 sin (— I' + 2 I — it1) + 2 + 2cos(— I' + 21 — it) (+ 2.33) (+ 2.65) — 0 .177 sin ( I — it1) / 21) (- 24) + 2cos( l-it) + o .209 sin ( /' — it1) + 5 cos ( I -it) (— 124.83) (—132.51) — 0 .466sin( 21'— I — it1) (+ 95) (+ 97) — 13 cos ( 2V — l — it) (- 17.45) (— 18.37) — 2 .477 sin ( SI' — 21 — it') (-174) (- 184) — 15 cos ( SI' — 21 — it) -+ 0.46 + 0.53 + 0 .452sin( 41' — SI — it1) + 7 + 6 + 9 cos ( it — 31 — it) + 0.11 + 0.07 + 0 .101sin( 51' — 41— it1) + 2 + 1 + 1 cos ( 6f — 41 — it) + 0.04 — 0.23 + o .027 sin ( 6 V — 5 1 — it1) 3 + 1 cos ( 9* — 52 — it) + 0.01 + o .014 sin ( 7 1' — 6 I — it1) + o .010 sin ( SI' — 11 — it') + o .006 sin ( 9 V — 8 1 — it1) + 0".002 sin (3 V — 2 1 + — it) + 0 .006 sin ( 2 V —it1 — it) (+16.08) (+17.01) + 0 .098 sin (81'— I — it' — it) (+ 33.73) (+ 36.67) + 0 .366sin( \l' — 21 — it' — it) (+ 2.56) (+ 3.35) + 0.688sin( 5 V — 3 1 — it1 — it) — 0 .136sin( 62' — 4Z — rf — it) — 0 .032 sin ( 7 1' — 5 1 — it1 — it) — 0 .019sin( 81' — 61 — it1 — it) — 0 .010sin( 9f — 71 — it' — it) — 0 .005sin(10f — SI — it' — IT) — 0".003sin( 22 — 2^) — 0 .011 sin ( V + 1 — 2 it') (-1-04) (-1.15) + 0 .005 sin (3 V — 1 — 2 it') (-4.29) (—4.79) — 0 .046 sin (4 V — 2 1 — 2 it') (—0.33) (—0.21) — 0 .090sin(5/' — Zl — 2it") + 0 .020 sin (6 V — 4 I — 2 it1) + 0 .005 sin (7 «' — 61 — 2rt') + 0 .002 sin (8T — 6Z — 2it') — 0".003sin( l'+ l — 2r) — 0 .016 sin (3 i'— 1 — 2r) — 0 .022 sin (4 I' - 2 I — 2 r) — 0 .041 sin (5 1' — 3 1 — 2 r) + 0 .006 sin (6 V — 4 1 — 2 T) Latitude. it) N. it) — 0" .004 sin (-41- + 5 / — r) it) — 0 ,008 sin (-81- + 41-T) it) — 0 023 sin (_2J' + 3i — T) it) — 0 ,056 sin (- ' + 21-T) it) + o .040 sin ( l-r) it) + 0, 106 sin ( f -') it) + o .320 sin ( 2V - l-r) it) + o .060 sin ( 31' — 21 — r) — 0 ,063 sin ( 41' — 3l — r) — 0, 01 6 sin ( 5F — 41 — T) — 0. 005 sin ( Gl' — 5J — T) — 0 .004 sin ( TV — 6 / — T) THE ORBIT OF NEPTUNE. 35 II.— ACTION OF SATURN. P. K. N. — 18".60 — 18".12 — 18".552 sin (V — I) + 0.15 + 0.15 + 0 .141 sin 2 (V — I) + 0 .02 + 0 .03 +0 .012 sin 3 (V — I) + 0 .06 +0 .000 sin 4 (V — I) + 0".002 sin (— V + I — * + «•) - 0 .006 sin ( 2 V — 2 I — ir1 + »r) } where The terms may then be put in the form { (p.2 — p^) sin o sin iA + (PI + p\) cos a cos i A } sin si' { (pz — pj) cos 0 sin i A — (p2 -f p^) sin &> cos i A } cos si' So that we may put $v = to. + P,.t sin I' + P,t cos Z' + Ps.2 sin 2 I + Pc.2 cos 2 1' 8 log r — 5 log r0 -f- Rtl sin Z' -f- P^ cos Z' where &v, P, and R are functions only of A, and may be tabulated as such. § 18. For Jupiter and Saturn, if we neglect those terms of which the coefficients are less than 0".03, it will be more convenient to tabulate the perturbations directly. This course we shall adopt, except with reference to those perturb- ations which depend on the mean longitude of Neptune alone, and do not contain the mean longitude of the disturbing planets. These have been omitted by both THE ORBIT OF NEPTUNE. 37 Peirce and Kowalski, as may be seen by reference to the preceding values of their coefficients. They are, in fact, very nearly confounded with the elliptic motion of the planet, but not exactly. We shall, at present, retain only the small resi- duals, after subducting those portions which are sensibly elliptic. The entire terms are as follows : 1. In the longitude. Action of Uranus, + 0".385 sinZ — 0".092 cosZ — 0".014 sin 2 1 — 0".002 cos 2 1 Saturn, + 0.099sinZ — 1.412cosZ — 0.018sin2Z — 0.020cos2Z Jupiter, +2.393 sinl — 0.567 cosZ + 0.018 sin 2? — 0.029 cos 2Z Total, + 2.877sinZ —2.071 cos? — 0.014sin2Z — 0.051 cos2Z (a) 2. In the logarithm of radius vector. Action of Uranus, -f- 1 sin Z +14 cos I Saturn, — 34 sin I Jupiter, — 11 sin I — 51 cos I Total, —44 sin Z —37 cos Z (Z>) « Changes in the functions e sin 7t and e cos n, represented by 5/t and 8k, will pro- duce the following changes in the longitude and log r, to = 2 Sfc sin Z — 2 Mi cos Z + f (We — 7tM) sin 2 Z — | (7^7i + Jfik) cos 2 Z <5 log r — — M §/i sin Z — M &k cos Z. Taking the elliptic terms to be subducted so that the coefficients of sin Z and cos Z shall vanish, we must put M = + 1".03G ; &• = + 1".438, which will produce the inequalities to = + 2".877 sin Z — 2".071 cos Z + 0".007 sin 2 Z— 0".037 cos 2 Z 6 log r — — 21 sin Z — 30 cos Z. Subtracting these elliptic inequalities from (a) and (I), we have for the residuals to = — 0".021 sin 2 I — 0".014 cos 2 Z <51ogr — — 23 sin Z — 7 cos Z. So that the constants of /*„ etc. are Constant of Psl — 0 P*= 0 Ps2-_0".021 Pc,= — 0.014 #,! = — 23 3a = - 7 38 THE ORBIT OF NEPTUNE. The constant terms in the coefficients Bsl and Bcl, which give the perturbations of the latitude, may be omitted without any error amounting to one hundredth of a second. § 19. The form of the preceding perturbations being different from that of the perturbations computed by Professor Peirce, the elliptic elements are next pro- visionally altered, so that the provisional theory shall be substantially identical with that already adopted. Small corrections have also been applied to the constants which determine the plane of the orbit. The provisional elements finally adopted for correction are as follows : e = 335° 5' 25".97 n= 7i = fc = p= q= 7864.421 + 1192 .93 + 1279 .36 +4910.17 —4137.46 Epoch, 1850, Jan. 0, Greenwich mean noon. Unit of time, 365.25 days. e= 0.00848055 e (in seconds) 1749".24 i 1°47' 1".95 n 42 59 52 .0 n 1-30 7 6.7 log a 1.4787523 The perturbations of the preceding elements are expressed in the following form : Put M = 21' — I Then, and T — Number j)f centuries after 1850, Jan. 0. M — 281° 43' 48" + 8° 26' 10".7 T; $h = 125".42 sin ( M— 0° 16'.3) + 36 .08 sin (2 M+ 1° 50') + 3. 58 sin (3 M+ 3° 42') + 1".32 T + constant. 3Jfe = 126".17 cos ( M— 0° 6'.2) + 36 .08 cos (2 M + 1° 50') + 3 .58 cos (3 M + 3° 42') + 0".31 T -\- constant. — 2247".52 sin ( M — 170° 32' 23") 5 log a = 1286 cos ( Af + 9° 8') + 98 .57 gin (2M+ 183° 24'.1) + 115 cos (2 M+ 4° 0') + 6 .81 sin (3 M + 186° 14') + constant. + 2144".26 T + const. + const. X T. + 2 .98 sin (2 M — 155° 38') + 1".10 T + constant. M— 61° 0') + 2 .98 cos (2 M — 155° 38') + 0".01 T + constant. THE ORBIT OF NEPTUNE. 39 The constants being so taken that the perturbations, and also the differential coefficient of 81, shall all vanish at the epoch 1850.0. These perturbations are given for the beginning of every tenth year, from 1GOO to 2000, in the following table : SECULAR AND LONG-PERIOD PERTURBATIONS OF THE ELEMENTS OF NEPTUNE FROM 1GOO TO 2000. Date a d logrt dh dk Sp 4 ¥ ¥ tt tr It n tt n n 1600 — 149.21 — 473 + 22.33 — 45.28 — 4.68 + 0.79 + 8.58 — 116.52 10 137.63 455 21.18 43.85 4.48 0.79 8.29 111.82 20 126.50 437 20.05 42.39 4.29 0.78 7.99 107.12 30 115.83 418 18.94 40.90 . 4.10 0.77 7.69 102.42 40 105.62 400 17.85 39.37 3.90 0.76 7.39 97.73 50 — 95.88 — 381 + 16.77 — 37.81 — 3.71 + 0.75 + 7.09 — 93.04 60 86.60 362 15.71 36.22 3.52 0.73 6.78 88.36 70 77.78 344 14.67 34.60 3.32 0.71 6.47 83.68 80 69.42 325 13.65 32.94 3.13 0.69 6.15 79.00 90 61.52 307 12.66 31.25 2.94 0.67 5.83 74.33 1700 — 54.09 — 288 + 11.69 — 29.53 — 2.75 + 0.64 + 5.50 — 69.66 10 47.13 269 10.74 27.77 2.56 0.61 5.17 64.99 20 40.65 250 9.81 25.99 2.37 0.58 4.84 60.32 30 34.65 231 8.90 24.17 2.18 0.55 4.49 55.66 40 29.13 212 8.01 22.33 2.00 0.52 4.14 51.01 50 — 24.09 — 193 + 7.14 — 20.45 — 1.81 + 0.48 + 3.79 — 46.36 60 19.52 174 '6.30 18.54 1.62 0.44 3.43 41.71 70 15.43 154 5.48 16.60 1.44 0.40 3.08 37.06 80 11.81 135 4.69 14.63 1.25 0.35 2.71 32.42 90 8.68 115 3.93 12.62 1.07 0.30 2.34 27.79 1800 — 6.03 — 96 + 3.20 — 10.59 — 0.89 + 0.25 + 1.96 — 23.15 10 3.86 77 2.50 8.53 0.71 0.20 1.58 18.52 20 2.17 57 1.83 6.44 0.53 0.15 1.20 13.88 30 0.96 38 1.19 4.32 0.35 0.10 0.81 9.25 40 — 0.24 — 19 + 0.58 — 2.17 --0.17 + 0.05 + 0.41 — 4.63 50 0.00 0 0.00 0.00 0.00 0.00 0.00 0.00 60 — 0.24 + 19 — 0.54 + 2.20 + 0.17 0.06 — 0.41 + 4.62 70 0.96 38 1.04 4.42 0.34 0.11 0.82 9.25 80 2.17 57 1.51 6.68 0.51 0.17 1.24 13.87 90 3.86 77 1.93 8.96 0.68 0.23 1.67 18.48 1900 — 6.03 + 96 — 2.32 + 11.26 + 0.85 — 0.29 — 2.10 + 23.09 10 8.68 115 2.67 13.59 1.01 0.35 2.54 27.70 20 11.81 133 2.98 15.94 1.17 0.42 2.98 32.30 30 15.44 152 3.25 18.31 1.33 0.49 3.43 36.90 40 19.53 171 3.47 20.70 1.48 0.56 3.89 41.49 50 — 24.10 + 190 — 3.65 + 23.11 -L1.64 — 0.63 — 4.35 + 46.09 60 29.14 209 3.79 25.54 1.80 0.70 4.81 50.69 70 34.66 227 3.89 27.99 1.95 0.77 5.28 55.28 80 40.66 246 3.94 30.46 2.11 0.84 5.75 59.88 90 47.13 265 3.94 32.95 2.26 0.91 6.23 64.47 2000 — 54.09 + 284 — 389 + 35.46 + 2.42 — 0.98 — 6.71 + 69.06 ftp and $q refer to the fixed ecliptic of 1850.0, 5p'and V*° tne movable ecliptic of the date, the motion being that adopted in Hanson's " Tables du Soleil," and concluded from the secular diminution of the obliquity there given. The corrections to the true longitude, latitude, and radius vector derived from the pure elliptic elements require corrections for these perturbations as follows : 40 THE ORBIT OF NEPTUNE. dv „ . dv „ . dv For the period during which Neptune has been observed, we have, to a sufficient degree of approximation, dv dl , -jj- — 2 COS /, an, d log r - dh -f- =. COS V, dp = 1, dv 0-7 -jj- = 2 sm Z: dk d log r _ ~~dk~~~ d{3 -j— = sin v. dq Theyalues of Ps_i, Pc,t, etc., derived from the perturbations by Uranus, are, putting A =: mean longitude of Uranus, minus that of Neptune, 0" .68.1 sin A — 5" .000 cos A 0 .400 sin 24 — , 11 .410 cos 2A + 0 .044 sin 3.4 4- 2 .031 cos SA + 0 .006 sin 4.4 + 0 .462 COS 44 + 0 .009 sin 54 4- 0 .165 COS -'..I + 0 .001 sin 64 + 0 .076 COS 64 — 0 .003 sin 7 A + 0 .035 COS 74 — 0 .002 sin 84 4- 0 .017 COS 84 — 0 .002 sin 9 A + 0 .008 COS 94 — 0 .001 sin 10 A 4- 0 .004 cos KM r.3 = — o".02i — 0 .254 cos A — 0 .867 cos 2 A — I .821 cos 3 A + 0 .355 cos 4 A 4- 0 .083 cos 5 A 4- 0 .039 cos 6 A 4- 0 .018 cos 7 A + 0 .008 cos 8 A + 0 .004 cos 9 A R^ = — 23 4- 4 cos 2 A — 0".038 sin A — 0 .035 sin 2 A — 0 .147 sin 3 A 4- 0 .023 sin 4 4 4- 0 .006 sin 5 A ,i = 4- 0".328 cos A 4- 0 .005 cos 2 4 — 0 .078 cos 3 A — 0 .022 cos 4 X — 0 .009 cos 5 A — 0 .006 cos 6 A — 58 sin A — 66 sin 2 A 4- 34 sin 3 A 4- 7 sin 4.4 4- 3 sin 5 A 4- 2 sin 6 A 4- 0".116 sin .4 4- 0 .048 sin 2 A — 0 .017 sin 3 A — 0 .003 sin 4 A + 4- .208 sin A — 0" 559 cos A + 10 .892 sin 2A — 0 .330 cos 2 A — l .989 sin 34 + 0 .078 cos 3 A — 0 .418 sin 4A + 0 .018 cos 4 A — 0 .135 sin 5 A + 0 .013 cos 54 — 0 .056 sin SA + 0 .003 cos 6 A — 0 .023 sin 1A — 0 .009 sin 8^4 — 0 .004 sin 94 — 0 .002 sin 10 A — 0".014 — 0 .022 cos A — 0 .027 cos 2 A — 0 .135 cos 34 4- 0 .025 cos 4 .4 4- 0 .008 cos 5 A 4- 0 .002 cos G .4 — 46 cos A — 70 cos 2 A 4- 32 cos 3 A 4- 9 cos 4 A 4- 3 cos 5 A 4- 2 cos 6 A 4- 0".148 cos A 4- 0 .002 cos 2 ^ — 0 .035 cos 3^4 — 0 .009 cos 4 A — 0 .004 cos 5 .4 4- 0".228 sin A 4- 0 .803 sin 2 4 4- 1 .849 sin 3 A — 0 .355 sin 4 A — 0 085 sin 5 A — 0 .041 sin 6 A — 0 .018 sin 1 A — 0 .008 sin 8 A — 0 .004 sin 9 A — 1 sin 3 A 4- 2 sin 4 4 — 0".256 sin A — 0 .105 sin 2 A 4- 0 .036 sin 3 A 4- 0 .008 sin 4 A THE ORBIT OF NEPTUNE. 41 The other terms in the longitude, logarithm of r, and latitude, representing the mean longitude of the planet by the initial letter of its name, are : Sv, = — 2". 949 sin A — 0".002 cos A 6r,= 314 cos A — 9.942sin2J. — 0.094cos24 + 162cos2X — 1.967 sin 3 A + 0 .016 cos 3 A + 38 cos 3 A — 0.610sin4.4 +0.004cos44 + 13cos4^1 — 0.237 sin 5 A -f 6 cos 5 A — 0.104sin64 + 2cos64 — 0 .041 sin 7 A — 0 .017 sin 8 A — 0 .007 sin 9 A + 18".552sin (S — N) + 397 cos (S — W) - 0 .137 sin 2 (S—;/) + 4 cos2 (S — JV) — 0 .012 sin 3 (S — #) — 0".524cos(2S— N) + 10 sin (2 S — N) + lcos(2S — JV) - 0.058sin5 + 0.047cosS + 4sin(S — 2N) + 4 cos (S — 2 JV) + O.lGGsin (S— 2N) — 0 .436 cos (S — 2 N) + 70lcos (J—N) + 34.121sin (J — N) + 4sm(2J—N') + 18cos(2^— N) - 0.011 sin 2 (J— N) — 5nin(J—2N) + 4 cos (J— 2N) + 0 .783 sin (2 J— N) — 0 .104 cos (2J— JV) — 0 .101 sin J" + 0.007 cos J + 0 .326sin(^ — 2N) + 0 .297 cos (J — 2 If) <5/3. = — 0".302 sin S + 0".OG5 cos S + 0".041 sin J + 0".5G3 cos J. It will be observed that in the perturbations of the longitude by Jupiter and Saturn we have neglected a number of small terms, the coefficients of the four largest of which are each about 0".03. The probable error in the theory pro- duced by this neglect is 0".04, and it was judged best, therefore, not to encumber it with them. But, should any one wish to include their effect, it can readily be calculated. Then, we have Provisional longitude of Neptune, referred to the mean equinox rr Precession, + Longitude in pure elliptic orbit, from elements page 39 + M + CP..I + 2 3&) sin Z + (Ptl — 2 3A) cos I + P,.2 sin 2 1 + Pc,2 cos 2 1 + Sv, -f- Reduction to ecliptic. Common logarithm of the radius vector = Log. radius vector in elliptic orbit - .0005920 + 8a + (fltl — MSK) sin I + (R^ — MM) cos I + 8r0. Latitude — Latitude in elliptic orbit (the longitude being increased by the perturbations), sin v + £,! — 8 cos v I is the mean longitude of Neptune, and v its true longitude in orbit, referred to the mean equinox of 1850.0. § 20. These formulae give the following heliocentric positions of Neptune : 6 May, 1865. 42 THE ORBIT OF NEPTUNE. Heliocentric co-ordinates of Neptune, referred to the mean equinox of date, for each ISOtft day, Greenwich mean noon. Date. Longitude. Latitude. log T. 0 / It 0 / H 1795, May 9, 215 5 20.12 + 1 47 59.80 1.4817427 1846, Jan. 21, 325 28 41.54 — 0 28 26.90 1.4774075 July 20, 326 33 58.15 0 30 23.48 3215 1847, Jan. 16, 327 39 13.82 0 32 19.44 2356 July 15, 328 44 28.74 0 34 14.63 1510 1848, Jan. 11, 329 49 43.21 0 36 9.15 1.4770685 July 9, 330 54 57.50 — 0 38 2.92 1.4769892 1849, Jan. 5, 332 0 11.98 0 39 55.91 9135 July 4, 333 5 27.14 0 41 48.06 8420 Dec. 31, 334 10 43.37 0 43 39.37 7742 1850, June 29, 335 16 1.07 0 45 29.78 7104 Dec. 26, 336 21 20.50 — 0 47 19.25 6503 1851, June 24, 337 26 42.10 0 49 7.76 5935 Dec. 21, 338 32 6.10 0 50 55.27 5396 1852, June 18, 339 37 32.77 0 52 41.71 4880 Dec. 15, 340 43 2.18 0 54 27.04 4383 1853, June 13, 341 48 34.62 — 0 56 11.23 3895 Dec. 10, 342 54 10.02 0 57 54.26 3405 1854, June 8, 343 59 48.28 0 59 36.04 2907 Dec. 5, 345 5 29.19 1 1 16.58 2395 1855, June 3, 346 11 12.34 1 2 55.79 1856 Nov. 30, 347 16 57.47 — 1 4 33.67 1281 1856, May 28, 348 22 43.95 1 6 10.17 0671 Nov. 24, 349 28 31.22 1 7 45.23 1.4760028 1857, May 23, 350 34 18.63 1 9 18.83 1.4759357 Nov. 19, 351 40 5.78 1 10 50.93 8652 1858, May 18, 352 45 52.17 — 1 12 21.48 7918 Nov. 14, 353 51 37.46 1 13 50.50 7185 1859, May 13, 354 57 21.65 1 15 17.89 6454 Nov. 9, 356 3 4.60 1 16 43.65 5739 1860, May 7, 357 8 46.65 1 18 7.79 5049 Nov. 3, 358 14 27.84 — 1 19 30.24 4394 1861, May 2, 359 20 8.66 1 20 50.95 3779 Oct. 29, 0 25 49.45 1 22 9.96 3210 1862, April 27, 1 31 30.52 1 23 27.19 2691 Oct. 24, 2 37 12.30 1 24 42.64 2220 1863, April 22, 3 42 55.16 — 1 25 56.24 1797 Oct. 19, 4 48 39.57 1 27 7.97 1423 1864, April 16, 5 54 25.74 1 28 17.84 1093 Oct. 13, 7 0 14.10 1 29 25.77 0801 1865, April 11, 8 6 4.93 — 1 30 31.79 1.4750547 THE OllBIT OF NEPTUNE. 43 From these heliocentric positions are concluded the following apparent geocentric positions, corrected for aberration, for the dates of the normal places to be given in the next chapter. Date. Geocentric Longitude. Geocentric Latitude. Date. Geocentric Longitude. Geocentric Latitude. O / /' O / " 0 // O / It 1795, May 9, 214 37 19.1 + 1 50 34.4 1856, Aug. 8, 349 54 3.3 — 1 8 44.8 1846, Oct. 14, 325 31 34.9 — 0 31 56.0 Sept. 13, 348 58 37.4 1 9 27.2 Nov. 14, 325 23 23.2 0 31 44.0 Oct. 26, 347 56 48.8 1 9 8.2 1847, July 20, 329 41 22.0 — 0 35 25.9 Nov. 17, 347 40 53.1 1 8 35.3 Aug. 17, 329 7 18.3 0 35 47.7 1857, Aug. 13, 352 5 16.5 — 1 12 6.2 Oct. 8, 827 52 10.4 0 35 58.8 Sept. 21, 351 4 2.0 1 12 46.1 Nov. 18, 327 36 56.3 0 35 38.6 Oct. 24, 350 16 9.6 1 12 28.3 1848, July 25, 331 58 5.0 — 0 39 22.8 Dec. 8, 349 54 1.4 1 11 11.8 Aug. 29, 331 3 15.8 0 39 55.2 1858, Aug. 18, 354 23 52.6 — 1 15 21.0 Oct. 6, 330 8 55.3 0 39 57.8 Sept. 23, 353 19 17.2 1 15 56.6 Nov. 17, 329 49 22.4 0 39 32.8 Oct. 28, 352 28 49.2 1 15 34.8 1849, Sept. 1, 333 15 38.6 ^0 43 52.7 Dec. 12, 352 8 46.7 1 14 11.8 Oct. 15, 332 15 32.4 0 43 49.2 1859, Aug. 21, 356 30 2.9 — 1 18 25.8 Nov. 25, 332 4 16.7 0 43 17.1 Sept. 23, 355 37 44.6 1 19 0.0 1850, Aug. 28, 335 39 38.5 — 0 47 42.7 Nov. 8, 354 34 29.4 1 18 23.0 Oct. 15, 334 31 9.5 0 47 41.1 Dec. 14, 354 22 52.5 1 17 9.3 Nov. 20, 334 15 23.8 0 47 9.5 1860, Aug. 20, 358 47 48.1 — 1 21 17.7 1851, Sept. 2, 337 48 58.1 — 0 51 33.7 Sept. 21, 357 54 28.1 1 21 56.4 Oct. 14, 336 48 10.9 0 51 30.0 Oct. 31, 356 58 22.4 1 21 32.2 Nov. 20, 336 28 31.0 0 50 54.1 Dec. 13, 356 36 24.7 1 20 4.6 1852, Aug. 7, 340 46 11.0 — 0 54 51.6 1861, Aug. 22, 1 2 42.4 — 1 24 6.0 Sept. 5, 340 0 10.3 0 55 19.5 Sept. 18, 0 21 7.6 1 24 42.2 Oct. 12, 339 5 43.0 0 55 14.8 Oct. 30, 359 16 38.4 1 24 24.6 Nov. 28, 338 43 23.4 0 54 23.3 Dec. 7, 358 50 3.3 1 23 7.9 1853, Sept. 1, 342 24 47.7 — 0 58 55.9 1862, Aug. 24, 3 17 34.7 — 1 26 46.7 Oct. 15, 341 19 0.2 0 58 52.4 Sept. 23, 2 31 7.7 1 27 25.7 Nov. 24, 340 56 3.0 0 58 4.7 Nov. 6, 1 25 26.1 1 26 57.3 1854, Aug. 30, 344 46 17.8 — 1 2 27.5 Dec. 15, 1 4 10.0 1 25 30.0 Sept. 24, 344 5 33.2 1 2 37.0 1863, Aug. 28, 5 29 46.2 — 1 29 23.7 Oct. 27, 343 23 17.3 1 2 15.3 Sept. 27, 4 42 49.6 1 30 0.3 Dec. 5, 343 12 2.8 1 1 19.1 Nov. 17, 3 30 58.0 1 29 12.5 1855, Aug. 10, 347 34 54.2 — 1 6 28.0 Dec. 12, 3 18 18.2 1 28 12.4 Sept. 8, 346 49 57.0 1 6 1.8 1864, Aug. 7, 8 9 20.6 — 1 30 53.7 Oct. 22, 345 45 6.2 1 5 50.1 Oct. 1, 6 52 56.7 1 32 27.0 Nov. 29, 345 24 25.3 — 1 4 54.8 Nov. 12, 5 51 37.8 1 31 49.1 Dec. 17, 5 32 27.7 — 1 30 23.1 The next step is to deduce positions of Neptune from observations, in order to compare them with the above theoretical positions. CHAPTER III. DISCUSSION OF THE OBSERVATIONS OF NEPTUNE. § 21. DURING the four years following the discovery of Neptune, observations of this planet, both meridian and extra-meridian, were very numerous. If the results of all these observations were free from constant errors, and, therefore, strictly comparable both with themselves and with subsequent observations, their combination would give very accurate positions of the planet. Unfortunately, however, we cannot assume that observations of different kinds, made at different observatories, are strictly comparable, nor have we, in many cases, the data for reducing them to a common standard. Let us consider, for instance, the meridian observations. Under the title of " Meridian Observations of Neptune," we find in astronomical periodicals series of observed Right Ascensions and Declinations. But right ascensions and declinations can never be really observed with any instrument. Only times of transit, and the readings of micrometers and other instruments, are really observed. The right ascensions and declinations of the planet are concluded from the observations, by the aid of a great number of subsidiary data, some relating to the stars, others to the instrument. Respecting these data we have, in most cases, absolutely no information whatever. But a knowledge of some of them, at least, is indispen- sable. Even if we grant that the instrumental errors are in all cases perfectly known for every observation, we still do not know either the names or the assumed right ascensions of the stars used in determining clock errors. Hence we cannot use the results, because the right ascensions given in standard catalogues not unfrequently differ by a second of space. The declinations of the planet are sometimes determined by comparison with standard stars, sometimes by measures of nadir distance, combined with the lati- tude of the observatory. The Paris observations are reduced by the former method ; those of most other observatories, by the latter. Using the latter method, it would naturally be supposed that the declinations from the observations of all observatories of which the latitudes are well determined ought to agree. But such is far from being the case. Compare, for instance, the declinations of funda- mental stars concluded from observations with the great transit circle at Green- wich with those in the Tabulse Reductionum of Wolfers, and we shall find that for stars more than 45° from the pole, the Greenwich positions are systematically nearly a second south of Wolfers', an amount greater than the probable error of a single isolated observation. We cannot impeach either authority. Wolfers' positions depend on such authorities as Pond, Struve, Argelandcr, Henderson, Airy, and Bessel. The conscientious care bestowed on the reduction of the Greenwich observations would seem to render their results unimpeachable. Besides, from a comparison of Winnecke's observations of his " Mars Stars" in 44 THE ORBIT OF NEPTUNE. 45 1862 with those of Greenwich, it would seem that the meridian circle of Pulkowa gives declinations an entire second farther south than those of the great transit circle ; so that had the Pulkowa instrument been employed on fundamental stars, their declinations would have been 2" less than Wolfers'. On the other hand, the Cambridge (Eng.) mural circle places the fundamental stars even farther north than Wolfers, and the Washington mural nearly as far north. It is foreign to our present purpose to speculate upon the causes of these dis- crepancies ; we are concerned only with their existence and amount. Their existence renders it absolutely necessary to correct the declinations as well as the right ascensions in order to reduce them to a common standard ; and no obser- vations have been used unless data for these corrections could be obtained. This rule necessitates the entire rejection of nearly all the vast mass of obser- vations on which Walker's theory was founded. In the case of the micrometric comparisons, no sufficient data seem to exist for determining the positions of the comparison stars ; the results are, therefore, heterogeneous in their character. However valuable they might have been when made, it will not be admissible, to combine them with the fifteen years of meridian observations made since. Micrometric observations were almost given up after 1850, and the planet was left to be followed by the meridian instruments of the larger observatories. The superior accuracy of this class of observations may be inferred from the fact that the comparatively small error in Walker's radius vector is made evident by them even during the period of construction of Walker's theory. A similar remark applies to the meridian observations. Four years of obser- vations made at a great number of observatories may be indiscriminately combined on the supposition that the systematic as well as the accidental errors will destroy each other, particularly if each series extends through the entire period. But, as few or none of these series made at observatories able to publish any thing but their results are continued later than 1849, it will not do to assume that the mean of their systematic errors, as fixed by the standard we have assumed, would vanish. The observations which fulfil the conditions we have indicated are made at observatories, as follows : Ancient observations. Paris, by Lalande, May 8 and 10 1795. Modern observations. Greenwich, 1846 to 1864. Cambridge, 1846 to 1857. Paris, 1856 to 1861. Washington, 1846 to 1850. Washington, 1861 to 1864. Hamburg, 1846 to 1849. Albany, 1861 to 1864. § 22. Reduction of Lalande s two observations of Neptune, May 8-10, 1795. The first of these observations is found in the Comptes Rendus, tome 24, p. 667. The second is in the Histoire Celeste, p. 158, and is the eighth star of the firsf 46 THE OKBIT OF NEPTUNE. column. They were made with the large mural quadrant of the observatory attached to the Military School. The Histoire Celeste does not seem to contain any definite information as to the observer or observers by whom the observa- tions were made. The stars of comparison which I shall select for the determination of the errors of the instrument and clock are the following : May 10. a Virginis, 1 Virginis, /I Virginis, 2 Librae, f.i Libra1, £' Librae. May8. /? Virginis, $ Corvi, q Virginis, •$/ Virginis, a Virginis, h Virginis, x Virginis, X Virginis, 2 Librae, s Libra?. These lists, I believe, include all of Bradley 's stars observed by Lalande on the dates in question within the zone of the planet, for which reliable modern positions can readily be obtained. Their positions for the year 1795 were obtained as follows. The positions given by Bessel in the Fundamenta Astronomic were reduced by the precessions there given to the mean equinox and equator of ITU"). (I. The modern positions were obtained from the Greenwich Twelve Year Catalogue, the Greenwich observations, or Eumker's Catalogue, and were also reduced to 1795.0 with Bessel's precessions. The difference of the results, being supposed due to proper motion, was divided proportionally to the time, and the concluded true position for 1795 obtained. As Lalande's observations arc subject to errors of several seconds, any farther refinement in investigating the positions of the stars would be a waste of labor. In the following table is exhibited the position of the star at the two epochs, referred to the mean equinox and equator of 1795.0, with the modern authorities, and the concluded mean positions for 1795.0 : For 1795.0. Concluded. Seconds of Year of > r l ,.., Secondsof Star. R. A., 1755. R. A., modern epoch. modern epoch. Modern authority. Dec. 1755. modern Dec. R. A. Dec. 6 Corvi, h. m. s. 12 19 16.36 s. 15.87 1850 12 T. C. 0 / // — 1522 13.2 // 28.7 h. m. s. 12 I'.l 16.1.1 / // — 15 22 19.7 q Virginis, 12 23 12.94 12.50 1840 12 Y. C. — 819 9.8 9.7 12 23 12.7:! — Sl'.i '.!.)• Y< Virginis, 12 43 42.28 42.40 1840 12 Y. C. — 825 17.5 21.9 12 43 42.34 — s 25 in.r> t Virginis, 13 15 54.88 54.32 1859 Or. Obs. 1859 — 11 38 6.2 10.0 13 15 54.116 -1138 7.7 h Virginis, 1322 11.38 11.30 1845 12 Y. C. — 9 611.5 15.1 13 22 11.34 — 96 13.1 K Virginis, 14 1 58.50 58.85 1840 12 Y. C. — 91839.3 37.3 14 1 58.67 — 9 18 :;s.-1 \ Virginis, 14 8 2.29 2.41 1840 12 Y. C. — 12 25 11.2 9.7 14 8 2.35 — 1225 10.5 2 Libraj, 14 12 25.07 25.17 1842 Rumker. — 1046 5.9 11.7 14 12 25.12 — 1040 8.'i fi Libra), 1438 C.33 6.19 1845 12 Y. C. — 1317 6.0 8.4 14 38 6.27 — 1317 7.1 f Librae, 14 43 16.60 ' 16.11 1842 Rumker. — 11 3 6.2 6.3 14 43 16.37 — 11 3 6.2 t Librae, 1513. 6.60 6.14 1842 Rumker. — 93422.7 57.6 1513 0.89 — 9 84 2!).r, THE ORBIT OF, NEPTUNE. 47 The above places were reduced to the dates of observation with the constants of the Tabulae Regiomontange. The apparent positions of/? Virginia and a Virginis are derived from the same work, correcting the Declination of the latter by + 0".60. The former is not used for index error, owing to its distance from the zone of Neptune. Intervals of wires. 0 On attempting to test the wire intervals of Lalande, H. C., p. 576, the interval of the third wire was found to exhibit well-marked systematic discrepancies. The observations of May 10 concur very well in indicating a diminution of OMO; and this correction has been applied to Lalande's intervals. The interval for wire 1 has not been changed. Deviation of- instrument. The next quantity required is the deviation of the instrument from the circle of Eight ascension of the planet. On using Lalande's value of this correction, stars of different altitudes, even in the zone of observation, gave inadmissible dis- crepancies. It is found necessary to reduce the value to less than half. This will be readily seen from the table below. Clock error, &c. The following tables give, for each star and each date — The number of wires observed, ^ meaning a doubtful observation. The concluded time of transit over the middle wire. Lalande's correction to this time for deviation of the middle wire, this deviation being supposed to vanish at the circle reading for Neptune, viz.: 60° 7'. The correction for deviation actually applied, derived from the comparison of clock corrections given by {$ Virginis and 8 Corvi. Seconds of apparent R. A. of star. The clock correction, using Lalande's deviation. The clock correction, using the concluded deviation. The weight assigned to the result for clock correction, depending on the number of wires, and the proximity of the star to the planet. For the second observation the deviation is of less importance than for the first, the planet being near the middle of the zone, and the mean of the cor- rections, therefore, very small. 48 THE ORBIT OF NEPTUXK. 1795, May 8. Name of star. N. T. D'. D. R. A. C'. C. W. h. m. s. a. a. S. a. s. /? Virginia, 1} 11 39 42.67 — 8.80 — 1.90 1.86 22 99 21.09 0 S Corvi, 2 12 18 55.85 + 0.81 + 0.40 17.31 2o!ec 21.06 1 q Virginia, 2 12 22 52.10 —0.60 — 0.30 13.84 22.34 22.04 2 4 Virginia, 1 12 43 22.00 —0.58 — 0.12!) 43.53 22.11 21.82 1 a Virginia, 3 13 14 4.23 —0.24 — 0.12 26.09 22.10 21.98 4 A Virginia, 2 13 21 50.55 —0.44 — 0.22 12.67 22.66 22.34 3 n Virginia, 3 14 1 38.57 —0.40 — 0.20 0.09 21.92 21.72 6 A Virginia, 3 14 7 41.80 + 0.20 + 0.10 3.81 21.81 21.91 6 2 Libras, 2 14 12 4.45 — 0.11 — 0.05 26.53 22.19 22.13 5 E Librae, 1J 15 12 46.07 — 0.34 — 0.17 7.89 22.16 21.99 '> May 10. a Virginia, 2 13 14 3.55 — 0.24 — 0.12 26.09 » 22.78 22.C.6 1 i Virginia, 2 13 15 32.90 + 0.06 + 0.03 65.99 28.08 23.06 1 ?. Virginia, 2 14 7 41.20 + 0.22 + 0.11 3.82 22.40 22.51 2 2 Libras, 2 14 12 3.40 — 0.11 — 0.06 26.53 23.24 23.19 2 fi Librie, 1 1437 45.10 + 0.39 + 0.20 7.79 22.80 22.49 1 f Librae, 2 14 42 64.95 — 0.06 — 0.03 17.88 ^>-> i)ij 22.98 1 We have then Clock time of transit of planet, Correction for clock and instrument, Concluded apparent Right Ascension, or, May 8. 14 11 36.50 + 21 .94 14 11 58.44 212° 59' 3G".G May 10. 14 11 23.50 + 22 .82 14 11 4G .32 212° 56' 34".8 We use Bessel's refractions, perature of the air, we have : May8, May 10. Beginning of observations, End " Declinations. For the height of the Barometer, and the tem- in. Bar. = 28 pou. 61. = 30.37 Eng. ; T= 13 Reau. = 61.2 Fah. Bar. = 28 pou. 3.1 1. = 30.12 Eng. ; T= 13.7 Reau. = 02.8 Fah. Bar. = 28 pou. 1.5 1. = 30.07 Eng. ; T= 13 Reau. = 61.2 Fah. The equatorial points on the circle are concluded as follows : May 8. May 10 t Name of Mar. Observed Z. Dist. Refrac- tion. Declination. Equato- rial point. Name of star. Observed Z. Dist. Refrac- tion. Declination. Equato- rial point. 48° 49' 48° 49' O t If / // n 0 // / n O 1 It tt S Corvi, 64 952 1 57.3 — 1522 29.0 20.3 rt Virginia, 5853 2 1 34.2 — 10 517.3 18.9 q Virginia, 57 7 11 28.0 — 8 19 17.6 21.5 t Virginia, I;D 2.-> r.-t 1 40.2 — 11 38 14.2 20.0 \ji Virginia, 57 13 17 28.4 — 82526.6 18.8 A Virginia, 61 12 50 1 43.5 — 1225 15.4 18.1 a Virginia, 5853 0 34.3 — 10 5 17.3 17.0 2 Librae, 59 33 59 1 36.8 — 1046 13.3 22.6 A Virginia, 5754 5 30.6 — 9 619.0 16.6 ft Librae, 62 443 1 47.3 — 13 17 10.7 18.6 K Virginia, 58 637 31.4 — 9 18 43.0 25.4 f Librae, 59 50 50 1 37.9 — 11 3 9.6 18.4 A Virginia, 61 12 43 43.5 — 12 2515.2 11.3 2 Librae, 59 33 57 36.9 — 104(1 13.1 20.8 ' Librae, 58 22 13 32.4 — 9 3431.7 13.7 THE ORBIT OF NEPTUNE. 49 Taking the means of the separate results for equatorial point, we have, for the apparent declinations of Neptune — May 8. May 10. • o ' // o i ft Observed circle reading, 60 8 17 60 7 19 Refraction, 1 39.0 1 39.0 Corrected circle reading, 60 9 56.0 60 8 58.0 Equatorial point, 48 49 18.4 48 49 19.6 ' Apparent declination, — 11 20 37.6 - 11 19 38.4 § 23. Probable errors of these positions. So far as we can judge from the discordance of the clock errors, and equatorial points derived from the several stars, the probable error of a single observation over a single wire in right ascension would appear to be about Os.27, and the pro- bable error of a single observed zenith distance about 2". 2. The agreement of the difference of the two observations with the computed motion of the planet shows that neither observation is affected with any abnormal error. We conclude, therefore, that the probable error of the normal place derived from the two obser- vations is about 2". 8 in R. A. and 1".5 in declination. Notwithstanding the magnitude of these probable errors, the observations will be very valuable during the remainder of the present century, owing to the weight with which they enter into the expressions of the elements. But in the twentieth century the observations made after 1846 will enable astronomers to compute the position of the planet in 1795 with a much higher degree of accuracy than La- lande could observe it. A similar remark applies to Lament's accidental zone observations in 1845. Valuable during the first two or three years, they afterward ceased to be so, because the theory soon became more accurate than the observation for an epoch so near the time of optical discovery. Had they been made in 1820, they would still have been valuable. Reduction of the modern observations. § 24. The modern observations will be treated in the following manner. The observations of each year will be divided into four groups, according to the time of culmination of the planet. The first group will include all observations made after h. m. h. m. 13 30 m. t. Second, between 10 30 and 13 30. Third, « 7 30 and 10 30. Fourth, all made before 7 30. The mean correction derived from each group will at first be regarded as the true correction applicable to the mean of the times of observation. This involves the supposition that the error of the ephemeris is changing uniformly during each series of observations. If we could compare with an ephemeris of the heliocentric 7 May, 1865. 50 THE ORBIT OF NEPTUNE. place of the planet, this hypothesis would be sufficiently near the truth for an entire year or more. But the error of geocentric place would be subject to an annual period though the errors of the heliocentric place should be invariable. Let us estimate the error of the hypothesis in question. Put r — radius vector of Neptune. D •=. difference of longitude of Sun and Neptune. fe, 5r, errors of heliocentric longitude and radius vector. Then the errors of geocentric longitude will be, appi'oximately, . /.. cosZ>\ $r . fr^l + — j+yi«n.ft Of this expression the part 8v Sr . „ - cos D + -j sin D r r2 will not be regularly progressive, but will change with the sine and cosine of D, the period of which is about 368 days. The integral of this expression gives 'for the mean value of the error, while/) is increasing from D0 to D^ $v sin Dl — sin D0 fir cos />, — cos /}, T A — A " ? ~A^A By putting t l- -u, and developing according to powers of 5, this expression becomes This, plus the error of heliocentric longitude, is the mean error which will be given by a series of observations equally scattered through a period + 8 on each side of the mean epoch D. But what we really want is the error at the mean epoch itself; that is, «• i OV n t -Of • 7-, dv + — cos D + -7, sm D; T r so that we must correct the mean error actually found by the quantity or, since 8 is generally about 1J, and r about 30, .027(1 eo-i + ^ri THE CEBIT OF NEPTUNE. 51 The maximum value of &v being less than 30", the first term will be entirely neglected. The value of &r sometimes amounts to .018, so that the correction arising from the second term may sometimes amount to 0".ll. We shall, there- fore, take account of it in a few cases. The ephemeris which will be compared with observation in order to deduce normal places of the planet will be the same with which the Greenwich obser- vations are compared, namely, "Walker's ephemeris until the year 1854, and Kowalski's ephemeris in subsequent years. It will be remembered, however, that these ephemerides are used only for the purpose of obtaining normal places, and in order to save the trouble of comparing every individual observation with the provisional theory. § 25. Mean corrections of the Ephemeris of Neptune given by observations at the different observatories, without correction for systematic differences. GREENWICH. CAMBRIDGE. Dale. K. A. Dec. No. Date. R.A. No. Dec. No. » If s It 18-16, Oct. 14, -0.050 + 0.48 12 1846, Oct. 13, — 0.014 10 + 1.51 8 Nov. 16, — .070 + 0.55 7 Nov. 7, .000 14 + 1.43 15 1847, July iv,. — .160 + 2.05 4 1847, July 27, — .062 6 + 2.30 4 Aug. 20, — .097 + 2.23 10 Aug. 22, — .090 18 + 2.25 17 Oct. 3, — .145 + 1.43 10 Oct. 8, — .100 14 + 2.18 13 Nov. 24, — .056 + 1.70 8 Nov. 20, — .022 13 + 0.66 14 1848, July 28, — .062 + 1.16 4 1848, July 22, — .056 8 + 0.88 8 Aug. 81, + .002 — 0.20 8 Aug. 27, — .048 19 + 1.85 19 Oct. 7, — .104 + 0.01 14 Oct. 9, -.018 16 + 0.75 17 Nov. 16, + .022 + 0.11 4 Nov. 19, + .009 10 + 1.05 11 1840, Sept. 3, — .027 + 0.65 6 1849, Aug. 21, — .087 16 + 0.72 18 Oct. 17, + .080 + 1.70 8 Oct. 15, — .038 16 — 0.17 16 Nov. 28, — .060 4-1.96 5 Nov. 22, + .090 11 + 0.21 2 1850, Aug. 27, — .079 — 1.00 13 1850, Aug. 29, — .089 10 + 0.48 11 Oct. 16, + .040 + 0.20 13 Oct. 16, + .011 14 — 0.13 15 Nov. 24, + .020 — 0.62 16 Nov. 23, + .039 12 + 0.14 13 1851, Sept. 1, — .162 — 1.07 16 1851, Sept. 4, — .054 18 — 1.62 19 Oct. 12, + .060 — 0.97 4 Oct. 17, + .028 11 — 1.61 10 Nov. 9, — .040 — 1.94 5 Nov. 28, + .014 9 — 1.91 10 1852, Aug. 7, — .260 — 2.34 5 1852, Aug. 29, — .037 15 — 1.53 15 Sept, 11, — .160 — 2.44 10 Oct. 11, — .048 10 — 2.52 11 Oct. 12, — .140 — 3.36 10 Dec. 4, + .038 7 — 2.99 7 Nov. 22, — .080 — 2.27 6 1853, Sept. 2, — .018 4 — 2.48 5 1853, Sept. 1, — .250 — 2.59 14 Oct. 24, — .134 13 — 3.04 13 Oct. 11, — .177 — 2.93 16 Nov. 27, + .031 11 — 2.53 12 Nov. 19, — .160 — 2.71 8 1854, Sept. 4, 1.314 11 — 3.59 12 1854, Aug. 30, — .420 — 3.60 13 Oct. 11, — .273 15 — 4.38 3 Sept. 21, — .370 — 3.94 11 Nov. 24, — .165 '4 — 6.17 8 Oct. 27, — .310 — 3.68 7 Dec. 5, — .300 — 4.36 4 f If 1855, Aug. 10, — .189 — 0.84 7 1855, Sept. 8, — 0.046 12 + 0.48 9 Sept. 8, — .046 — 0.06 16 Oct. 12, + 0.50 6 Oct. 22, + .183 + 0.80 6 Dec. 10, + 0.206 9 + 3.07 7 Nov. 29, + .177 + 1.51 6 1856, Sept, 12, — 0.099 9 + 0.05 8 1856, Aug. 8, — .220 — 1.06 10 Oct. 29, + 0.120 8 + 1.73 7 Sept. 13, — .080 — 1.06 7 Nov. 28, + 0.164 5 + 2.50 6 Oct. 26, + .076 + 1.41 9 1857, Sept. 14, — 0.030 9 — 0.83 12 Nov. 17, + .123 + 1.67 6 Oct. 25, + 0.104 5 — 0.34 5 1857, Aug. 14, — .356 — 2.43 6 Dec. 11, + 0.175 8 + 0.16 9 Sept. 22, — .130 — 0.50 12 Oct. 24, + .oso + 0.29 5 Dec. 5, + .130 + 0.16 10 1858, Aug. 18, — .301 — 1.74 14 Sept. 24, — .260 — 1.81 13 Oct. 25, — .200 -1.00 16 Dec. 10, — .058 — 0.76 11 1850, Aug. 19, — .500 — 3.27 9 Sept. 28, — .416 — 8.11 17 Nov. 3, — .315 — 2.56 15 Dec. 16, — .328 — 1.46 10 52 THE OllBIT OF NEPTUNE. GREENWICH (Cont.). PARIS (Walker). Date. H. A. Dec. No. Date. R. A. No. Dec. No. a l 1860, Aug. 20, _ 0.760 —5.02 4 1856, Sept. 14, — 0.669 ' 12 —3.96 - 8 Sept. 20, — 0.685 —3.86 13 Oct. 2"), — 0.606 14 —8.91 15 Oct. 31, — O.G62 —3.38 15 Dec. l!l. — 0.470 2 Dec. 13, _ 0.630 —4.73 2 1857, Sept. 19, — 0.768 10 —4.98 10 1861, Aug. 22, _ 0.040 —5.41 4 Oct. 25, — 0.825 13 —5.95' 12 Sept. 18, — 0.861 —5.62 16 Dec. 14, — 0.729 7 —6.13 7 Oct. 30, — 0.861 —5.18 12 Dec. 7, — 0.993 —5.14 7 1862, Aug. 24, — .12 —7.20 6 PARIS (Kowalski). Sept. 25, — .162 —6.76 13 Date. R. A. No. Dec. No. Nov. 4, ... .139 —7.00 11 g Dec. 17, 1863, Aug. 28, — .18 —7.06 _ .585 —9.91 4 2 1858, Sept. 21, Oct. 27, — 0.291 18 —1.14 — 0.235 19 —0.76 17 19 Sept. 23, Nov. 12, Dec. 15, _ .461 —8.62 — .388 —8.33 — .375 —8.41 9 4 2 1859, Aug. 23, Sept. 23, Nov. 17, — 0.630 5 —2.64 — 0.474 9 —2.50 — 0.337 11 —1.92 5 8 14 1864, Oct. 3, — .680 »— 11.03 8 Dec. 7, — 0.430 2 —2.20 2 Nov. 8, — .639 —10.52 7 1860, Sept. 29, — 0.608 6 —3.75 6 Oct. 31, — 0.618 12 —3.51 10 1861, Sept. 28, — 0.960 7 —5.56 7 WASHINGTON (Walker's Eph.). Nov. 4, — 0.948 17 —5.52 17 Date. R. A. No. Dec. No. Dec. 9, — 0.890 5 —5.60 4 1 1846, Nov. 9, 1847, Aug. 23, 4-0.096 10 -)- 2. 1C — 0.205 15 +2.27 7 6 HAMBURG. Oct. 14, — 0.023 9 4-1-80 7 Date. R.A. Dec. No. Nov. 8, + 0.052 5 +1.96 3 s " 1848, Aug. 30, — 0.076 10 +0.80 14 1846, Oct. 7, _ 0.098 —1.43 9 Oct. 2, — 0.121 12 +1.71 10 Nov. 21, — 0.131 +0.10 16 1849, Sept. 11, — 0.154 5 1847, Aug. 22, _ 0.061 —1.43 17 Oct. 12, — 0.014 8 +1.06 6 Oct. 10, — 0.102 +0.10 22 1850, Oct. 13, — 0.032 9 + 0.94 25 Nov. 26, — 0.051 +0.32 12 Nov. 11, — 0.068 5 +1.25 13 1848, July 20, 0.000 —0.20 7 Aug. 27, — 0.118 —2.17 15 1861, Oct. 29, — 1.695 6 —8.70 5 Oct. 4, _ 0.043 —2.15 12 Dec. 16, — 1.593 11 —8.64 10 1849, Sept. 3, _0.014 —0.92 9 1862, Sept. 23, — 2.000 2 Oct. 10, _ 0.008 —0.50 16 Nov. 14, — 1.860 3 — 9.85 2 Nov. 25, + 0.071 —0.71 10 Dec. 12, — 1.827 C —10.9 1 1863, Oct. 13, — 2.22 3 —13.82 5 Nov. 12, — 2.19 3 —13.52 6 ALBANY (Walker). Dec. 8, — 2.054 5 —12.76 7 Date. R. A. No. Dec. No. 1864, Aug. 7, — 2.69 3 —15.5 4 Nov. 17, Dec. 20, — 2.52 5 —14.6 — 2.38 5 —14.0 12 2 1862, Aug. 25, Sept, 21, — 1.927 3 —13.05 — 1.905 14 —13.67 4 17 Oct. 81, — 1.815 9 —13.46 10 Dec. 17, — 1.732 6 -12.73 6 ALBANY (Kowalski). 1863, Sept. 27, — 2.228 12 — 14.96 1 Date. R. A. No. Dec. No. Nov. 6, — 2.145 10 —15.38 9 g ' Dec. 14, — 2.053 6 —14.80 6 1861, Sept. 1, Nov. 11, — 0.778 5 —6.02 — 0.825 8 —5.42 5 8 1864, Sept. 29, Nov. 9, — 2.490 6 —17.70 — 2.437 9 -16.29 6 9 Dec. 14, — 0.847 9 —5.44 9 Dec. 14, — 2.360 3 —16.27 3 THE ORBIT OF NEPTUNE. 53 § 20. Corrections to the observed 2>ositions in order to render them strictly com- parable with each other. These corrections have been derived from a comparison of the positions of the ten fundamental clock stars, from y Aquilre to a Ceti inclusive, given by obser- vations at the different observatories, with the adopted standard positions. The standard right ascensions are those of Dr. Gould, prepared for the United States Coast Survey. The declinations are those of Wolfers in the " Tabulte Reduc- tionum," diminished by 0".50. Both are given in the following table : R. A. 1850.0. Annual var. 1850. Dec. 1850.0. Annual var. 1850. Cor. to Am. Eph. R. A. Deo. h. m. s. s. O r If ft 7 Aquiloo, 19 39 7.08 + 2.853 + 1015 5.02 + 8.41 + 2 — 2 a Aquils!, 19 43 27.82 2.928 + 8 28 33.45 9.13 — 1 + 5 ft Aquilie, 1947 50.f,7 2.948 + 62 8.08 8.62 + 3 + 5 a2 Cupricorni, 20 9 43.69 3.335 — 13 020.90 10.77 + 2 + 13 a Aquarii, 21 58 4.fi8 3.084 — 1 2 47.41 17.28 + 4 + 8 a Pegnsi, 22 57 17.50 2.983 + 14 23 57.36 19.30 0 + 1 a Andromeda;, 0 038.57 3.085 + 28 1543.72 19.91 + 2 0 7 Peg.-isi, 0 5 30.99 3.081 + 14 20 57.67 20.04 + 2 + 1 a Arietis, 1 58 43. G4 3.304 + 2244 1.97 17.29 + 1 0 a Ceti, 2 54 2(5.58 + 3.130 + 3 29 52.45 + 14.42 + 6 + 5 In reducing the Albany observations, it was found advisable to add o Piscium to the number of standard stars for determining these corrections. Its assumed position is R. A. 18GO.O. 23 51 7.42 Declination 1800.0. + 6 0 5' 17". 9 The observed mean right ascensions and declinations of these stars, reduced to the beginnings of the several years, have been compared with those derived from the above table, giving the result from each star a weight proportional to the number of observations when the observations were few in number, but giving each result equal weight when they were numerous. Thus the following sys- tematic corrections have been derived: OllKKXWICII. CAMBRIDGE. WASHINGTON. R. A. Dec. m R. A. Dec. R. A. Dec. s " " » " 1810 + 0.044 — 0.04 1846 -1.21 1840 + 0.034 — 0.34 47 + 0.059 — 0.19 47 -0.99 47 + 0.057 — 0.41 48 + 0.08 48 — 0.25 48 + 0.036 — 0.57 49 :-,(> — 1.51 — 0.52 49 50 s — O.OS8 — 0.05 — 0.80 49 ) 50 j + 0.0:19 — 1.04 51 — 0.020 — 0.22 51 — 0.052 — 1.17 01 + 0.058 — 0.89 52 + 0.21 52 — 0.20 63 — 0.09 54 + 0.18 53 — 0.75 04 — 1.37 r,.-, + 0.05 54 — 0.044 -0.73 50 — 0.038 + 0.30 57 — 0.052 00 — 0.005 01 0.003 + 0.24 02 63 + 0.63 + 0.27 PABIS. ALBANY. OY. Cat. » n 8 „ of 1854 — 0.020 1850 + 0.020 — 0.57 1801 + 0.006 + 0.17 7V. Cot. 58 + 0.021 — 0.23 02 000 0.00 of 1800 + 0.002 00 + 0.023 — 0.53 03 000 + 0.78 04 000 + 0.97 54 THE ORBIT OF NEPTUNE. REMARKS ON THE PRECEDING CORRECTIONS. GREENWICH. The corrections actually applied to the right ascensions from 1848 to 1853 have been derived by comparing the corrections on p. IV. of the introduction to the Green- wich six-year catalogue for 1854 with the corrections given by that catalogue, namely, — 0'.020. From 1857 to 1864 the corrections have been derived in the same way from the seven-year catalogue for 18GO. The entire list of corrections is as follows : 1846, + 0'.044 47, + 0 .059 48, + 0 .052 49-55, — 0.010 56, — 0.025 57-61, — 0.008 62-64, + 0 .002 The corrections to the declination have been concluded from year to year from the table. CAMBRIDGE. One consistent set of adopted right ascensions having been used in the re- ductions of the Cambridge observations, the constant correction — Os.046 has been applied to the right ascensions throughout. The declinations have been corrected as follows : 1846-47, — 1".12 1848-57, — 0 .58 WASHINGTON. The corrections to the Washington right ascensions from 1S46 to 1850 have ]>ecn derived from a general comparison of twenty-five fundamental stars near the equator with the results of the Greenwich observations. The mean -f ()".(J42 has been adopted as the constant correction for those years. After 1861, no correction is needed, Dr. Gould's Right ascensions having been adopted in the reductions. The corrections to the declinations for 18G1 have been derived from those for 1862. The latter were diminished by 0".20 for error of nadir point, while no such correction was applied to the former. HAMBURG. Having applied to Charles Rumker, Esq., M.A., of the observatory at Hamburg, fur information respecting the data used in the reduction of the Hamburg obser- vations of Neptune, I was informed that both right ascensions and declinations THE ORBIT OF NEPTUNE. 55 depended on the positions of the Nautical Almanac stars. For the years 1846-47, the Nautical Almanac right ascensions require the constant correction — 0'.003, and in 1848-49 the correction +0*.049, to reduce them to those adopted. The declinations do not seem so easily reducible to our adopted standard. They are, therefore, not included. All the Washington, and some of the Paris and Albany, observations having been compared with Walker's Ephemeris in years subsequent to 1855, the fol- lowing corrections have been applied for differences of Ephemerides : To Paris Corrections. Date. R. A. Dec. s 1856, Sept. 14, +0.54 +4.68 Oct. 25, +0.65 +5.75 1857, Sept. 19, +0.676 +5.02 Oct. 25, +0.80 +5.82 Dec. 14, +0.80 +5.92 To Washington and Albany Corrections. Date. R. A. Dec. 1861, Oct. 29, + 0 s .76 + 5 .5 Dec. 16, + 0 .70 + 4 .9 1862, Aug. 25, + 0 .90 + 6 .3 Sept. 21, + 0.85 + 6.2 23, + 0.85 + 6 .-2 Oct. 31, + 0.76 + 5 A Nov. 14, + 0.75 + 5 .0 Dec. 12, + 0.70 + 5.1 17, + 0.70 + 5 .1 1863, Sept. 27, + 0.845 + 5 .9 Oct. 13, + 0.81 + 5.6 Nov. 6, + 0.78 + 5.3 12, + 0.77 + 5.5 Dec. 8, + 0. 73 + 5. 2 14, + 0.73 + 5.2 1864, Aug. 7, + 0.91 + 6.2 Sept. 29, + 0. 87 + 6. 0 Nov. 9, + 0. 90 + 5. 9 17, + 0. 88 + 5. 5 Dec. 14, + 0. 82 + 5. 8 20, + 0. 82 + 5. 5 56 THE ORBIT OF NEPTUNE. § 27. The concluded corrections of the ephemeris for normal dates generally near the mean of the means have been concluded by applying to the corrections of pp. 51, 52 the following corrections : 1. Correction for systematic error given by fundamental stars. 2. Reduction, when the change of error was rapid, from the dates of the means to the dates of the normals. 3. 0.027 ^-jf sin D for second differences of error, when 8r > .01. 4. Correction just given for difference of epheme rides. The results are given in the following table. The small figures show the relative weights assigned to the separate results, which are, to a certain extent, a matter of judgment, but which are assigned without any reference to the magni- tude of the correction itself. THE ORBIT OF NEPTUNE. 57 CORRECTIONS TO THE TABULAR RIGHT ASCENSIONS GIVEN BY THE DIFFERENT OBSERVATORIES, WITH THE CONCLUDED CORRECTIONS AND CONCLUDED NORMAL RIGHT ASCENSIONS. (The units are hundredths of seconds of time.) Gr. Cam. Par. Wash. Ham. Con- cluded. Tab. R.A. R. A. from Observation. s. h. m. s. 1846, Oct. 14, -15 -6. -10, — 4 55.02 21 51 54.98 Nov. 14, -*, -53 + 145 -13, + 1 22.99 21 51 23.00 1847, July 26, -9, -11. 9 1.94 22 8 1.85 Aug. 17, — 4. -14, -166 -9, — 11 51.90 22 551.79 Oct. 8, -95 -142 + 25 -103 — 6 3.42 22 1 3.36 Nov. 18, 0, —7, + 93 -5, 0 4.28 22 0 4.28 1848, July 25, -la -10, + 5, - 3 49.85 22 16 49.82 Aug. 29, •fS. — 9, -8, -7i — 2 21.55 22 13 21.53 Oct. 6, -6. -6, -85 + 1. — 5 53.89 22 953.84 Nov. 17, + 73 —4, + 3 38.40 22 838.43 1849, Sept. 1, -4., -13, -12, + 8, -7 51.43 22 21 51.36 Oct. 15, + 74 -8, + 36 + •*, + 2 2.74 22 18 2.76 Nov. 25, — 7. +4, -2, + 12. + 1 19.06 22 17 19.07 1850, Aug. 28, -», -14, — 10 62.59 2231 2.49 Oct. 15, + 35 -4, + 1. + 1 43.45 22 26 43.46 Nov. 20, + !• -1, -23 + o 42.94 22 25 42.94 1851, Sept. 2, -17, —Mb — 15 15.94 22 39 15.79 Oct. 14, + 53 -2, + 2 2G.94 22 35 26.96 Nov. 20, — 5, -8, — 4 11.92 22 34 11.88 1852, Aug. 7, -273 — 27 25.60 22 50 25.33 Sept. 5, — 17, — S2 — 15 34.10 22 47 33.95 Oct. 12, -16, -9, — 13 9.83 2244 9.70 Nov. 28, - 93 -1, — 7 44.70 22 42 44.63 1853, Sept. 1, -266 -9, — 24 40.14 22 56 39.90 Oct. 15, — 18, -18, — 18 34.47 22 52 34.29 Nov. 24, -17, -2, — 8 7.41 22 51 7.33 1854, Aug. 30, -48, -373 — 41 32.47 23 5 32.06 Sept, 24, -385 — 38 1.25 23 3 0.87 Oct. 27, -324 — 83, — 33 23.38 23 0 23.05 Dec. 5, -31, -21, — 27 40.04 22 59 39.77 1855, Aug. 10, -20U — 20 2.20 23 16 2.00 Sept. 8, - 6a -106 — 7 16.50 23 13 16.43 Oct. 22, + 17,, + 17 15.60 23 9 15.77 Nov. 29, + 17,, + 15, + 16 57.33 23 7 57.49 8 May, 1865. 58 THE ORBIT OF NEPTUNE. CORRECTIONS TO THE TABULAR RIGHT ASCENSIONS GIVEN BY THE DIFFERENT OBSERVATORIES, WITH THE CONCLUDED CORRECTIONS AND CONCLUDED NORMAL RIGHT ASCENSIONS (Cont.). (The units are hundredths of seconds of time.) Gr. Cam. Par. Wash. Albany. Con- cluded. Tab. E.A. R. A. from Observation. s. h. m. s. 1856, Aug. 8, -25M — 25 41.68 23 24 41.43 Sept. 13, llu -145 -153 — 12 17.95 23 21 17.83 Oct. 26, + 5,8 + 6, + 6 28.76 23 17 28.82 Nov. 17, + 11,, + lll + 11 28.90 23 16 29.01 1857, Aug. 13, -37,, — 37 50.90 23 32 50.53 Sept. 21, -142, -5. -62 — 12 6.08 23 29 5.96 Oct. 24, + 2 8.91 23 26 8.93 Dec. 8, + H« + 13S + 92 + 11 45.10 23 24 45.21 1858, Aug. 18, -40M — 40 58.46 23 40 58.06 Sept. 23, -27* -275 — 27 29.38 23 27 29.11 Oct. 28,' -2032 -21, — 20 22.93 23 34 22.73 Dec. 12, — 6 6.89 2333 6.83 1859, Aug. 21, -51*. -61, — 52 14.82 23 49 14.30 Sept. 23, — 46,0 — 452 — 46 3.51 2346 3.05 Nov. 8, -32a -323 — 32 9.94 2342 9.62 Dec. 14, — 33B — 41, — 33 25.27 23 41 24.94 1860, Aug. 20, -77,, — 77 45.29 23 57 44.52 Sept. 23, -69ffi -592 — 68 30.53 23 54 29.85 Oct. 31, — 67ffi -60, — 66 3.89 23 51 3.23 Dec. 13, -636 — 63 40.91 23 49 40.28 1861, Aug. 22, -95,. — 95 4.99 0 6 4.04 Sept. 18, -8730 -942 -778 — 86 33.38 0 3 32.52 Oct. 30, — 87,,, -935 -88,8 -828 — 88 36.27 23 59 35.39 Dec. 7, - 10015 -87, — 84,, — 84, — 89 56.66 23 57 55.77 1862, Aug. 24, — 112,6 — 103, — 109 24.31 0 14 23.22 Sept. 23, — 11625 - 115. - 10515 — 113 34.92 0 11 33.79 Nov. 6, 114M -111,8 -105,o — 112 33.12 0 7 32.00 Dec. 15, - US,, — 113* — 1038 — 112 12.76 0 6 11.64 1863, Aug. 28, -1595 — 159 34.01 0 22 32.42 Sept. 27, — 146M -1418 — 138,o — 144 42.64 0 19 41.20 Nov. 17, - 138,o -1418 — 1368 — 140 17.57 0 25 16.17 Dec. 12, — 1376 - 13212 -1328 — 133 29.48 0 14 28.15 1834, Aug. 7, -178, — 178 22.99 0 32 21.21 Oct. 1, - 1688 -1628 — 167 44.63 0 27 42.96 Nov. 12, — 16315 -164,5 — 154, — 162 58.31 0 23 56.69 Dec. 17, - 15615 — 154, — 157 45.62 0 22 44.05 THE ORBIT OF NEPTUNE. 50 CORRECTION TO THE DECLINATIONS, WITH THE CONCLUDED DECLINATIONS. Gr. Cam. Par. Wash. Albany. Con- cluded. Tab. Dec. Concluded Dec. from Obs. 1846, Oct. 14, n + 0.44 + 0.42 + 0.4 ft 20.6 of n — 13 31 20.2 Nov. 14, + 0.53 + 0.33 + 1.8, + 0.9 54.7 13 33 53.8 1847, July 26, + 1.92 + 1.2, + 1.7 31.0 — 12 8 29.3 Aug. 17, + 2.0, + 1.1, + 1.83 + 1.7 48.0 12 20 46.3 Oct. 8, + 1.2, + 1.1, + 1.4, + 1.2 6.2 1247 5.0 Nov. 18, + 1.63 -0.53 + 1-5: + 0.7 2.6 12 52 1.9 1848, July 25, + 1.2, + 0.32 + 0.8 39.6 — 112338.8 Aug. 29, + OJ, + 1.3, + 0.2, + 0.5 44.9 11 43 44.4 Oct. 6, + o.i5 + 0.23 + 1.1, + 0.5 3.1 12 3 2.6 Nov. 17, + 0.2, + 0.52 + 0.4 32.9 12 932.5 1849, Sept. 1, — 0.93 + 0.1, — 0.4 55.1 — 10 59 55.5 Oct. 15, + 0.23 -0.83 + 0.0, — 0.2 33.0 11 21 33.2 Nov. 25, + 1.4, -0.43 + 0.3 5.2 11 25 4.9 1850, Aug. 28, -1.55 -0.12 — 1.1 52.6 — 10 10 53.7 Oct. 15, — 0.35 -0.7, -0.15 — 0.3 59.4 10 35 59.7 Nov. 20, -1.0, -0.43 + 0.24 — 0.5 15.3 10 41 15.8 1851, Sept. 2, -1.8, -2.2, — 1.6 27.6 — 9 26 29.2 Oct. 14, - 1.2, -2,2, — 1.7 3.1 949 4.8 Nov. 20, — 2.22 — 2.52 — 2.4 45.9 9 55 48.3 1852, Aug. 7, -2.1, — 2.1 44.2 — 8 22 46.3 Sept. 5, -2.2, -2.13' — 2.2 37.0 8 40 39.2 Oct. 12, -8.1, -3.12 — 3.1 5.7 9 1 8.8 Nov. 28, -2.13 — 3.6, -2.7 42.2 9 844.9 1853, Sept. 1, -2.45 -3.1, — 2.5 53.0 — 7 48 55.5 Oct. 15, -2.7, — 3.G3 — 3.1 58.4 8 14 1.5 Nov. 24, — 2.5, -3.13 — 2.9 58.5 822 1.4 1854, Aug. 30, -3.44 -4.23 -3.7 39.1 — 6 57 42.8 Sept. 24, — 3.84 — 3.8 32.9 7 13 36.7 Oct. 27, —8.5, -5.1, — 3.9 30.6 7 29 34.5 Dec. 5, -4.12 — 5.72 — 4.9 58.1 733 3.0 1855, Aug. 10, — 0.83 — 0.8 54.9 — 55455.7 Sept. 8, 0.05 -0.12 0.0 59.8 6 12 59.8 Oct. 22, + 0.93 + 0.2, + 0.7 4.1 638 3.4 Nov. 29, + l.G3 + 2.52 + 2.0 15.2 — 6 45 13.2 60 THE ORBIT OF NEPTUNE. CORRECTION TO TUB DECLINATIONS, WITH THE CONCLUDED DECLINATIONS (Cont.). Gr. Cam. Par. Wash. Albany. Con- cluded. Tab. Dec. Concluded Dec. from Obs. 1856, Aug. 8, n — 0.84 — 0.8 n 21.4 0 1 II — 5 3 22.2 Sept. 13, -0.7, — 0.5, + 0.1, — 0.4 48.3 5 25 48.7 Oct. 26, + 1-7, + 1-1, + 1.3, + 1.4 45.4 5 49 44.0 Nov. 17, + 2.0, + 1.7, + 1.9 29.2 5 55 27.3 1857, Aug. 13, — 2.0, — 2.0 40.8 — 4 14 42.8 Sept. 21, —0.1. -1.33 -0.4, — 0.5 29.9 4 39 30.4 Oct. 24, + 0.7, — 0.9, — 0.5, — 0.2 6.4 4 58 6.6 Dec. 8, + 0.6, -0.4, — 0.6, 0.0 39.0 5 5 39.0 1858, Aug. 18, -1.8, — 1.3 44.6 — 32545.9 Sept. 23, -1.34 -1-4, — 1.3 55.2 3 48 56.5 Oct. 28, — 0.65 — 1.0, — 0.8 34.7 4 8 35.5 Dec. 12, — 0.35 -0.3 14.2 4 15 14.5 1859, Aug. 21, -2.9, — 3.0, — 2.9 26.2 — 2 35 29.1 Sept. 23, -2.7, - 2.9, — 2.8 45.6 2 56 48.4 Nov. 8, -2.15 -2.33 — 2.2 19.5 3 21 21.7 Dec. 14, -1.0, — 2.6, — 1.5 48.4 3 24 49.9 1860, Aug. 20, -4.7, — 4.7 13.8 — 143 18.5 Sept. 23, — 3.65 -4.2, — 3.8 3.1 2 5 6.9 Oct. 31, •-3.15 -4.0, — 3.4 0.3 2 27 3.7 Dec. 13, -4.4, — 4.4 24.1 2 34 28.5 1861, Aug. 22, -5.2, — 5.2 4.6 — 052 9.8 Sept. 18, -5.4, -6.1, — 5.8, — 5.6 10.8 1 9 16.4 Oct. 30, -4.9, -6.1, -4.1, — 5.3, — 5.1 35.1 1 34 40.2 Dec. 7, -4.9, -6.1, -4.6, — 5.3, — 5.2 59.8 — 1 44 5.0 1862, Aug. 24, — 6.6, — 6.6 53.0 — 0 0 59.6 Sept. 23, -6.15 — 7.50 — 6.1 56.3 0 20 2.4 Nov. 6, — 6.3< -5.7, -8.4. — 6.1 38.0 0 45 44.1 Dec. 15, -6.4, -6.7, -7.60 — 6.5 45.8 — 05252.3 1863, Aug. 28, — 9.6, — 9.6 11.6 + 049 2.0 Sept. 27, -8.4, — 8.92 -8.4, — 8.5 61.5 0 29 53.0 Nov. 17, -8.1, -8.7, — 9.34 — 8.8 13.6 + 0 2 4.8 Dec. 12, -8.1, — 8.2, -8.8, — 8.6 53.1 -0 2 1.7 1864, Aug. 7, - 10.7, — 10.7 53.8 + 1 50 43.1 Oct. 1, — 10.8, - 10.7, — 10.7 19.0 1 19 8.3 Nov. 12, - 10.2, — 10.5, - 9.4, — 10.1 3S.7 0 55 28.6 Dec. 17, - 9.9, — 9.5, - 9.7 21.3 + 049 11.6 . THE ORBIT OF NEPTUNE. 61 REMARKS ON THE PRECEDING TABLE. The processes to which we have subjected the observations ought, it would seem, to eliminate every source of constant differences between those made at different observatories. But there are still two well-marked cases of systematic differences in the right ascensions, namely, in the Cambridge observations of the first five years, and the Albany observations of the last four. The differences between the corrections finally concluded from all the observations, and those concluded from Cambridge and Albany, are, it will be seen, as follows : Date. Cone. — Camb. Date. Cone. — Albany. S S 1846, Oct. + 0.02 1861, Sept. — 0.09 Nov. +0.06 Oct. —0.06 1847, July, +0.02 Dec. —0.05 Aug. + 0.03 1862, Aug. — 0.06 Oct. +0.08 Sept. -0.08 Nov. +0.07 Nov. —0.07 1848, July, + 0.07 Dec. — 0.09 Aug. + 0.07 1863, Sept. — 0.06 Oct. +0.01 Nov. —0.04 Nov. +0.07 Dec. —0.01 1849, Sept. + 0.06 1864, Oct. - 0.05 Oct. +0.10 Nov. -0.08 Nov. —0.03 Dec. —0.03 1850, Aug. + 0.04 Oct. + 0.05 Nov. + 0.01 The constancy of signs here exhibited can hardly be attributed to chance in the case of Cambridge, and not at all in the case of Albany. The only cause to which I can attribute it is a habit of registering the transit of Neptune earlier or later than that of a bright star. Such a habit would seem to pertain to the observer rather than the instrument, and, therefore, less to be feared as the number of observers is increased. On account of its possible existence, the weights of the results of any one observatory have not been supposed proportional to the number of observations, but each has been subject to a constant probable error of at least 0'.02 when observations were made by eye and ear, and Os.01 when made with chronograph, however great the number of observations. Albany exhibits the anomaly that the real systematic error seems greater than the probable accidental error. The latter is of the smallest class, as might be anticipated from the facts that the observations are made with a first-class in- strument, in a good atmosphere, and are recorded with the electro-chronograph. They have, therefore, been treated in such a way that, while they should enter the absolute longitudes with a very small weight, they should enter the relative longitudes at different times of the year, in other words, the radius vector, with 62 THE ORBIT OF NEPTUNE. as much weight as those of any other observatory. This has been effected by applying the constant correction — Os.04 to all the results before combining them. Anomalies somewhat similar are exhibited by the Paris declinations from I860 to 1861, and by the Washington declinations of 1861. In the case of Wash- ington, they may be accounted for by the circumstance that the systematic cor- rections for 1861 depend mainly on observations made in 1863, very few declina- tions of fundamental stars being observed in 1861-62. But it does not seem so easy to account for the discrepancy between the Paris and Greenwich results. A comparison of them shows that while the Paris observations systematically place the ten fundamental stars adopted as our standard about 0".8 farther north than Greenwich, their positions of Neptune, and of some small stars near the equator, substantially agree. § 28. The preceding normal right ascensions and declinations are next con- verted into apparent ecliptic longitudes and latitudes, for the purpose of com- parison with the provisional theory. For this purpose Hansen's obliquity of the ecliptic has been adopted, so as to agree with the motion of the ecliptic adopted in the preceding chapter. In the following table we give for each date — 1. The longitude from observation, obtained as just stated. 2. The seconds of longitude from provisional theory, as given on p. 43. 3. The excess of the theoretical over the observed longitude. 4, 5, 6. The corresponding quantities relative to the latitude. THE OK 15 IT OF NEPTUNE. GEOCENTRIC APPARENT LONGITUDES AND LATITUDES OF NEPTUNE DERIVED FROM OBSERVATION. Longitude. Latitude. TJ, _ ~ T^WOT* rif Date. jji roi 01 Theory. ! . 1 I ' ' 1 ' < \ Theory. Observation. Theory. Observation. Theory. 1795, May 9, O 1 tf 214 37 20.4 // 19.1 ff -1.3 + 1 50 33.3 34.4 + 1.1 1846, Oct. 14, 325 31 35.0 34.9 — 0.1 — 0 31 55.8 56.0 — 0.2 Nov. 14, 325 23 24.2 23.2 — 1.0 0 31 43.5 44.0 — 0.5 1847, July 26, 329 41 22.9 22.0 — 0.9 0 35 24.1 25.9 — 1.8 Aug. 17, 329 7 18.9 18.3 — 0.6 0 35 45.7 47.7 — 2.0 Oct. 8, 327 52 10.4 10.4 0.0 0 35 57.6 58.8 — 1.2 Nov. 18, 327 36 56.9 56.3 — 0.6 0 35 38.3 38.6 — 0.3 1848, July 25, 331 59 6.7 5.0 — 1.7 0 39 21.8 22.8 — 1.0 Aug. 29, 331 3 16.6 15.8 — 0.8 0 39 54.0 55.2 — 1.2 Oct. 6, 330 8 55.3 55.3 0.0 0 39 56.8 57.8 — 1.0 Nov. 17, 329 59 22.8 22.4 — 0.4 0 39 32.3 32.8 — 0.5 1849, Sept. 1, 333 15 38.7 38.6 — 0.1 0 43 51.8 52.7 — 0.9 Oct. 15, 332 15 32.6 32.4 — 0.2 0 43 48.6 49.2 — 0.6 Nov. 25, 332 417.1 16.7 — 0.4 0 43 15.7 17.1 — 1.4 1850, Aug. 28, 335 39 38.5 38.5 0.0 04741.9 42.7 — 0.8 Oct. 15, 334 31 10.3 9.5 — 0.8 0 47 39.9 41.1 — 1.2 Nov. 20, 334 15 24.4 23.8 — 0.6 047 8.6 9.5 — 0.9 1851, Sept. 2, 337 48 58.5 58.1 — 0.4 0 51 32.6 33.7 — 1.1 Oct. 14, 336 48 12.7 10.9 — 1.8 0 51 30.0 30.0 0.0 Nov. 20, 336 28 32.5 . 31.9 — 0.6 0 50 53.3 54.1 — 0.8 1852, Aug. 7, 340 46 10.7 11.0 + 0.3 0 54 49.8 51.6 — 1.8 Sept. 5, 340 0 11.1 10.3 — 0.8 0 55 18.8 19.5 — 0.7 Oct. 12, 339 543.2 43.0 — 0.2 0 55 14.6 14.8 0 2 Nov. 28, 338 43 24.0 23.4 — 0.6 0 54 23.4 23.3 + 01 1853, Sept. 1, 342 24 48.0 47.7 — 0.3 0 58 54.1 55.9 — 1.8 Oct. 15, 341 19 0.8 0.2 — 0.6 0 58 52.0 52.4 — 0.4 Nov. 24, 340 56 4.3 3.0 — 1.3 058 4.5 4.7 — 0.2 1854, Aug. 30, 344 46 18.1 17.8 — 0.3 1 2 25.8 27.5 — 1.7 Kept. 24, 344 533.4 33.2 — 0.2 1 2 35.8 37.0 — 1.2 Oct. 27, 343 23 17.5 17.3 — 0.2 1 2 14.4 15.3 — 0.9 Dec. 5, 343 12 3.1 2.8 — 0.3 1 1 19.4 19.1 + 0.3 1855, Aug. 10, 347 34 55.1 54.2 — 0.9 1 5 26.8 28.0 — 1.2 Sept. 8, 346 49 57.9 57.0 — 0.9 1 6 1.4 1.8 — 0.4 Oct. 22, 34545 7.4 6.2 — 1.2 1 5 50.2 50.1 + 0.1 Nov. 29, 345 24 25.6 25.3 — 0.3 1 4 53.7 54.8 — 1.1 G4 THE ORBIT OF NEPTUNE. GEOCENTRIC APPARENT LONGITUDES AND LATITUDES OF NEPTUNE DERIVED FROM OBSERVATION (Cont.). Longitude. Latitude. I-'i-]', ,1- r\f T? Date. Observation. Theory. -Lji rui ui Theory. Observation. Theory. -ftri'or oi Theory. 1856, Aug. 8, O / tf 349 54 4.2 n 3.3 ff — 0.9 — 1 843.7 44.8 — 1.1 Sept. 13, 348 58 37.9 37.4 — 0.5 1 9 26.5 27.2 — 0.7 Oct. 26, 347 56 49.5 48.8 — 0.7 1 9 7.1 8.2 — 1.1 Nov. 17, 347 40 53.7 53.1 — 0.6 1 834.0 35.3 — 1.3 1857, Aug. 13, 352 5 16.8 16.5 — 0.3 1 12 5.6 6.2 — 0.6 Sept. 21, 351 4 3.1 2.0 — 1.1 1 12 45.6 46.1 — 0.5 Oct. 24, 350 16 10.7 9.6 — 1.1 1 12 28.3 28.3 0.0 Dec. 8, 349 54 2.4 1.4 — 1.0 - 1 11 11.8 11.8 0.0 1858, Aug. 18, 354 16 21.7 20.9 — 0.8 1 15 19.7 21.0 — 1.3 Sept. 23, 353 19 17.3 17.2 — 0.1 1 15 56.1 56.6 — 0.5 Oct. 28, 352 28 49.3 49.2 — 0.1 1 15 34.2 34.8 — 0.6 Doc. 12, 352 848.3 46.7 — 1.6 1 14 11.6 11.8 — 0.2 1859, Aug. 21, 356 30 3.7 2.9 — 0.8 1 18 25.2 25.8 — 0.6 Sept. 23, 355 37 45.0 44.6 — 0.4 1 18 59.5 60.0 — 0.5 Nov. 8, 354 34 30.3 29.4 — 0.9 1 18 22.8 23.0 — 0.2 Dec. 14, 354 22 53.5 52.5 — 1.0 1 17 8.5 9.3 — 0.8 1860, Aug. 20, 358 47 47.9 48.1 + 0.2 1 21 17.0 17.7 — 0.7 Sept. 23, 357 54 28.9 28.1 — 0.8 1 21 55.4 5(i.4 — 1.0 Oct. 31, 356 58 23.5 22.4 — 1.1 1 21 31.1 32.2 — 1.1 Dec. 13, 356 36 25.2 24.7 — 0.5 1 20 4.5 4.6 — 0.1 1861, Aug. 22, 1 243.6 42.4 — 1.2 1 24 4.8 6.0 — 1.2 Sept. 18, 0 21 9.6 7.6 — 2.0 1 24 41.8 42.2 — 0.4 Oct. 30, 359 16 40.6 38.4 — 2.2 1 24 24.0 24.6 — 0.6 Dec. 7, 358 50 4.3 3.3 — 1.0 1 23 7.0 7.9 — 0.9 1862, Aug. 24, 3 17 37.0 34.7 — 2.3 1 26 46.0 46.7 — 0.7 Sept. 23, 2 31 9.8 7.7 — 2.1 1 27 24.2 25.7 — 1.5 Nov. 6, 1 25 28.0 26.1 — 1.9 1 26 56.1 57.3 — 1.2 Dec. 15, 1 4 11.5 10.0 — 1.5 1 25 29.0 30.0 — 1.0 1863, Aug. 28, 5 29 46.2 46.2 0.0 1 29 22.8 23.7 — 0.9 Sept. 27, 4 42 51.8 49.6 — 2.2 1 29 59.4 60.3 — 0.9 Nov. 17, 3 30 59.6 58.0 — 1.6 1 29 12.1 12.5 — 0.4 Dec. 12, 3 18 20.4 18.2 — 2.2 1 28 12.1 12.4 — 0.3 1864, Aug. 7, 8 9 22.8 20.6 — 2.2 1 30 52.9 53.7 — o.s Oct. 1, 6 52 59.8 56.7 — 3.1 1 32 26.8 27.0 — 0.2 Nov. 12, 5 51 40.4 37.8 — 2.6 1 31 48.0 49.1 — 1.1 Dec. 17, 5 32 30.3 27.7 — 2.6 — 13022.6 23.1 — 0.5 CHAPTER IV. RESULTS OF THE COMPARISON OF THE THEORETICAL WITH THE OBSERVED POSITIONS OF NEPTUNE. § 29. THE first question of the present chapter will be whether the observations of Neptune can be satisfied within the limits of their probable errors by suitable changes in the elements of the orbit of Neptune and the masses of the disturbing planets. No admissible change in the mass either of Jupiter or Saturn will sensibly affect the perturbations of Neptune. The mass of Uranus will, therefore, be the only one the correction of which need be taken into account. The errors of the provisional latitude of Neptune are so small that the errors of the longitude in orbit may be taken as sensibly the same with the errors of ecliptic longitude. The latter give equations of condition between the following unknown quantities. Correction of the mean longitude of Neptune, mean motion of Neptune, eccentricity X sm- perihelion of Neptune. " eccentricity X cos- perihelion of Neptune. " " mass of Uranus. But if we attempt to solve by least squares the equations between these cor- rections, we shall be met with the difficulty set forth in the introduction, and our normal equations will be equivalent to only three, unless we include a great number of decimals in the computation. We shall, therefore, make a linear transformation of the unknown quantities, on the principles already referred to, and suggested by the following considerations. The true longitude of Neptune has been less than its mean longitude, and its true motion has been greater than its mean motion, ever since its optical discovery. From these circumstances the difficulty in question arises. We may obviate it by substituting for the mean longitude and mean motion of Neptune during an entire revolution its average longitude and heliocentric motion during the period of the modern observations. Suppose an imaginary planet to move uniformly in the orbit of Neptune in such a way that its average longitude and motion have been the same as the average longitude and motion of Neptune during the last nineteen years, and let x be its longitude, 1850, Jan. 0, and xf its annual motion. We may then make the eccentricity and perihelion of Neptune to depend ana- lytically upon the deviation of its motion from that of the hypothetical planet, as it must depend really, because this deviation is the only real datum which we to reason from, the Lalande observations excepted. It is to be remarked 9 May, 1865. 65 66 THE ORBIT OF NEPTUNE. that both the longitude and motion of the hypothetical planet are entirely arbitrary. For the differential coefficients of the elements with respect to the heliocentric co-ordinates, we have - — 1 + 2 k cos I + 2 h sin I. (.IE dv dv dn ~ de ' dv dh -JT — — 2 cos I — f h sin 2 I — | k cos 2 I. t3Q -TT=. 2 sin I + I k sin 2 7 — | h cos 2 I. ct/c \ dr . - -j— — /•: sin I — li cos t. « ae 1 d> _ J^ t_ dr_ a dn ~ 3 an a de 7r — — sin I + h — k sin 2 I + A cos 2 I. a dh — z= — cos 7 + Z; — 7i sin 2 Z — k cos 2 Z. a dk In accordance with what has been proposed, we shall substitute for s and n the quantities x and a', connected with them by the relations x •=. e + ah -\- (3k ... . af = n + a'h a and ft being approximately the average values of — 2 cos Z and + 2 sin Z during the last nineteen years, and a' and ft' the average values of 2 n sin Z and 2 n cos Z during the same time. We shall take a = — 1.77 a' = — 0.018 ft = — 0.85 P' = + 0.073. Then, considering v as a function of x, y, It, and /•;, and enclosing the new dif- ferential coefficients in parentheses, we have, by suitable transformations, dv\ dv {dv\_dv (c]^\ — dr_. i1^]— — di ' Vcfcey dn ' \dx / de ' \dstf / dn dv /dv \ dv . dv ( -71- ) — 77 (« + « 0 -j- \dh / dh ' de THE OKJ3IT OF NEPTUNE. 67 ( , Putting 2, for the geocentric longitude, .and A for the distance from the earth, the differential coefficients of the geocentric with respect to the heliocentric co- ordinates will be - parent, errors ot theory. 8th series, 1863-1864, + 2.8% — l.2(i 3 + o.93 — —2.4 —0.9^ 7 —0.34 — 0.13p —0.3 +0.7^ 7 -0.04 + 0.10^ — 2.0 + 0.9,u 6 —0.33 +0.15^ § 32. The coefficients of (i, taken negatively, represent the changes which would be produced in the residuals if we suppose the mass of Uranus to be nothing. It will be seen that these coefficients are generally smaller than the residuals them- selves, and that their actual effect on the modern residuals never amounts to more than four-tenths of a second. Supposing that the modern observations cannot be relied on within this limit of error, we should arrive at this remarkable result, — that if the planet Uranus were unknown, its existence could scarcely be inferred from all the observations hitherto made on Neptune, unless these were combined in such -a way as to show the systematic error of the theoretical radius vector. In fact, the orbit of Neptune, computed without regard to the perturb- ations of Uranus, would only exhibit an error of 9" when compared with Lalande's position ; and a discussion of the modern observations would exhibit no sensible error in the heliocentric longitudes. This circumstance furnishes a very good illustration of the propriety of developing the long-period perturbations, the co- efficients of which amount to whole minutes, as perturbations of the elements which shall vanish at the epoch 1850. Under these circumstances, no reliable correction of the mass of Uranus can be concluded from the motions of Neptune. The solution of the preceding residuals does, indeed, indicate an increase of this mass by one-third, which seems altogether inadmissible, and is certainly very unreliable. Of the twenty-nine residuals, fifteen indicate an increase of the mass, thirteen a diminution, and for one the coefficient of ^ vanishes : so that the increase of the mass of Uranus is indicated only by the fact that the residuals which favor it are generally a little larger than those which do not. § 33. If Uranus could scarcely be detected from the motions of Neptune, much less can an extra-Neptunian planet, unless it happened to be nearly in conjunction with Neptune at the present time, and to have a much greater mass than Uranus, — a highly improbable combination of circumstances. That there is no present indication of any such action is shown by the smallness of the apparent mean errors of theory in heliocentric longitude and radius vector during the whole period from 1846 to 1864. The following table shows the mean value of these errors during each of the seven series of modern observations, and the error of the geocentric longitude of the Lalande observations, putting fj. zz 0. The error of radius vector is expressed as error of annual parallax. It will be remembered that the first of the four equations of each series arise from observations made about half-way between the first quadrature and the opposition, the second at opposition, the third between opposition and last quadrature, and the fourth near the last quadrature. Each series, therefore, gives four equations of the first degree between the errors of heliocentric longitude &>•, and annual parallax fy>. THE OKBIT OF NEPTUNE. 73 The coefficient of 8v will be sensibly unity, and that of fy will vary from about • — 0.5 to + 1.0 in each series. Error of theory by tJie Lalande observations. + 2".3 (It will be remembered that the probable error of the Lalande position was estimated at 2".8 ; but, owing to the over-estimate of the comparative precision of the modern observations, the weight assigned to this position in the equations of condition corresponded to a probable error of rather more than 4".) By modern observations. Limiting dates. Error of longitude. Error of parallax. 1846-47, — O."o5 — o"l8 1848-50, -0.08 —0.03 1851-53, —0.07 +0.55 1854-56, —0.08 0.00 1857-59, + 0.22 + 0.23 1860-62, + 0.11 + 0.18 1863-64, + 0.02 + 0.28 These errors are as small as could be expected if the theory were perfect. There is, therefore, no indication of the action of an extra-Neptunian planet. But this fact does not militate against the existence of such a planet. The per- turbations of a planet, and its elliptic elements, develop themselves, not in pro- portion to the time, but in proportion to the square of the arc described. .In order, therefore, to determine the errors of a slow-moving planet with as much accuracy as those of a quick-moving one, we must observe it through a period pro- portioned to its time of revolution. And we cannot detect a deviation of long period from an elliptic orbit until we have accumulated data much more than sufficient for the exact determination of the elliptic elements. For example, when the position of Neptune was determined from the perturbations of Uranus, the latter planet had been regularly observed through an arc of some 270°. Moreover, the two planets had been in conjunction in 1824. They are also remarkably near each other when in conjunction. Yet, with all these circumstances so favorable to the development of large perturbations, Uranus only wandered about 5" from an elliptic orbit during the entire period of the modern observations. Perturbations will, at first, be developed in proportion to the square of the arc passed over. Therefore, had Uranus been observed through an arc of only 120°, the perturbations by Neptune would have been indicated only by deviations in heliocentric longitude of less than I". It is, therefore, almost vain to hope for the detection of an extra-Neptunian planet from the motions of Neptune before the close of the present century. § 34. Determination of the position of the plane of the orbit of Neptune. To determine the corrections of the constants p and q, which determine the 10 Hay, 1865. 74 THE ORBIT OF NEPTUNE. position of the plane of the orbit, '\ve shall divide the residuals of latitude into five groups, the last one including three years, and each of the others four years. To find the heliocentric angular distance of the planet above the plane of its assumed orbit, we shall take an indiscriminate mean of the errors of geocentric latitude of each group, multiply it by 0.98 to reduce it to heliocentric error, and correct it for the mean error in longitude. The mean errors of geocentric latitude, with the equations to which they give rise, are as follows. The probable errors of each modern mean is estimated at 0".15 : so that the Lalaude position is entitled to a precision of ^ Limiting Dates. tp Equation of Condition. n n 1795, + 1.1 0=+0.08% —0.0585? + 0.11 1846-49, — 0.97 — 0.866 —0.500 — 0.96 1850-53, — 0.75 — 0.934 —0.358 — 0.75 1854-57, — 0.71 — 0.978 —0.208 — 0.71 1858-61, — 0.67 _0.999 —0.052 — 0.68 1862-64, — 0.79 — 0.996 +0.084 — 0.80 The solution of which by least squares gives lip = — 0".73 ; Sq = — 0".41. The residuals, multiplying the first by 10 to reduce it to actual observed error, are 1795, + o"7 1846-49, —0.13 1850-53, + 0.07 1854-57, + 0.09 1858-61, + 0.07 1862-64, —0.10 So that the Lalande observation is represented within 0".7, notwithstanding the small weight with which it enters the equations. In fact, if p and q were determined from the modern observations alone, the Lalande position would still be represented within about 0".7. § 35. Concluded elements of Neptune. From equations (1) and (2) of this chapter, we have & =te + 1.77 M +0.85 87,:; 0.0185A - 0.073&fe; the concluded corrections to the So that, making the mass of Uranus ^T provisional elements of § 19 are THE ORBIT OF NEPTUNE. & = + 12M «»= + 0.5144 37* = + 8.76 •&fc = — 3.79 $p = — 0.73 fy = _ 0.41 Applying these corrections to the provisional elements of § 19, they become e = 335 5 38.91 n= 7864.9354 h= +1201.69 k= +1275.57 2)= +4909.44 q= —4137.87 75 CHAPTER V. TABLES OF NEPTUNE. § 30. F/II/I/IIHH i/ttt/ theory. The fundamental theory on which these tables are founded is as follows : 1. Undisturbed elements of Neptime, referred to the m«ut /!i- / the epocli. h zz eccentricity X *mc perihelion zz -f- 1201.69 k — eccentricity X cos perihelion zz -f- 1275.57 p •=. sine inclination X gine node zz -j- 4909.44 q zz sine inclination X cos node zz — 4137.87 n zzmean motion in 365^ days zz 7864.935 E zz mean longitude at epoch zz 335° 5' 38".91 Epoch 1850, Jan. 0, Greemvich mean noon. From these expressions we deduce •n zz43°17'30".3 e - 0.0084962 log a zz 1.4781414 Period zz 164.782 Julian years. In log a we have included the constants of log ?• introduced by the action of the planets, and also the effect of the secular variation of the longitude of the epoch, both of which are computed on p. 31. 2. Secular and long-period, perturbations of the above elements. These are taken without change from the table p. 39. The elements being corrected by the addition of these perturbations for the epoch of computation, we thence deduce the elliptic place of the planet. 3. Perturbations of the co-ordinates. To the elliptic place of the planet we apply corrections for- periodic perturb- ations of the co-ordinates, as follows : To the longitude in orbit, Ptl sin I + Pc.j cos I + Ps,2 sin 2 / -f Pc.2 cos 2 1 + &v To the logarithm of the radius vector, Rsl sin I + Rcj cos I + 5r0. To the north latitude, computed with the true longitude in orbit, B, , sin v -\- J3cl cos v -f fy?o- 70 TABLES OF NEPTUNE. 77 All these quantities have the same values as in § 19, pp. 40 and 41. The elliptic values of the co-ordinates being thus corrected, we have the helio- centric co-ordinates resulting from the concluded theory. To facilitate this computation, the following tables are constructed. They are designed to give the means of determining, for any date between the years 1600 and 2000, the principal auxiliary quantities which will be needed in computing the place of the planet from the above theory. Many of these quantities are modified so that the computer shall be troubled as little as possible with difference of signs. Thus, to all the quantities Ps, Pa Rs, etc. constants are added so that they shall always be positive, and so that the signs of the products which form the perturbations shall be the same as those of sin /, cos I, etc. Again, constants are added to all the perturbations of the longitude and radius vector, to make them positive. § 37. Data given in the several tables. TABLE I. gives the values of the " epochs and arguments" for the beginning of each fourth year from 1800 to 1952 inclusive, the years 1800 and 1900 beginning with Greenwich mean noon of Jan. 0, and all the other years with that of Jan. 1. Pis simply the number of the four-year cycle before 1900, by which I' and & 1900 Y of the next table must be multiplied, or - — 7 , adding a unit for fractions. I is the mean longitude in orbit of Neptune, affected with the long-period per- turbations of that clement, p. 39, and referred to the mean equinox of 1850.0. y is the negative of the longitude of the node affected by perturbations, counted on the orbit of the planet from that point which is equally distant from the node of 1850 with the equinox of 1850, and diminished by 1°, the sum of the constants added to the equations of longitude. 6 is the longitude of the node, referred to the mean equinox of the epoch, and diminished by 1', the constant added to the reduction to the ecliptic. In the arguments 1 to 9 inclusive, the circle is divided into 400 parts. Repre- senting the mean longitude of a planet, referred to the equinox of 1850.0 by its initial letter, the values of the different arguments are as follows : Arg. 1 = U — N, " 2 = S —N, " 3 = J — N, « 4 = 2S— N, " 5 = S, « G = S —2N, " 7 = 2J— N, « S = J, " Q=J —2N. •>> Thus, Arg, 1 gives the difference of the mean longitudes of Uranus and Neptune, expressed in parts 100 of which make a quadrant ; and so of the other arguments. At the bottom of the table the expression A[}^)is the change in the longitude or the argument during that 180 days which commences with 1850, Jan. 0. 78 TABLES OF NEPTUNE. Fact. T gives the change in A[{g0) during a century : so that the change in any 180-day period within one or two centuries of the epoch may be found by mul- tiplying Fact. T by the fraction of a century after 1850.0 at which the 180-day period commences, and applying it to Aj}^). A$so) gives the second difference for any series of 180-day periods within one or two centuries of 1850 : so that, knowing the first value of Aj}^,, we can find a series of values by successive addition. The period of 180 days has been selected as a convenient one for computing a heliocentric ephemeris. If any other period, represented by JVdays, be preferred, the corresponding values of A(1) and A(2) are found by multiplying and A$o> by j. TABLE II. gives the change of each longitude and argument for the first day of each month during a four-year cycle. The change in I is given for that cycle which begins with 1900 and ends with 1904. Column ?' gives, in units of the second decimal of seconds, the change in column I during one cycle. Hence, multiplying I' by the whole number P of the preceding table, and adding the units of the product to the hundredths of seconds of /, we have the change of mean longitude during the cycle numbered P in Table I. The correction is positive for years before 1900, because the mean motion is diminishing. 0 must be corrected in precisely the same way ; but here the correction is nega- tive before 1900. Rigorously, both y and 0 require correction similar to I. But it is not requisite that either of these quantities should be accurate within a second, so long as their sum is exactly equal to the precession diminished by 1° 1'. The four-year changes of both y and 6, which destroy each other, are, therefore, neglected ; but the change in 0 due to the secular variation of the constant of precession (0".0227) is allowed for by the correction P6'. TABLE III. gives the reduction from the first to the subsequent days of any month, or the motion of the epochs and arguments during a number of days one less than those on the left of the table. TABLE IV. gives the corrections to be applied to the longitudes and arguments for the epochs 1800 -H to reduce them to the epochs 1GOO + t, 1700 + 1, and 1900 -f- 1, respectively. They are expressed in the form a0 + T X Fact. T + T- X Fact. T\ in which Tis the fraction of a century. TABLE V. gives the expressions for the perturbations of the longitude produced by Uranus. To each of the expressions 7^, and Pct 14" has l>een added, and to Ps2 and Pcx 3" has been added. Hence, when these quantities, as given in the TABLES OP NEPTUNE. 79 tables, are multiplied by sin I, cos I, sin 2 Z, and cos 2 Z, the sum will be too great by the quantity 14" sin I + 14" cos I + 3" sin 2 I + 3" cos 2 Z, which expression has been subtracted from the equation of the centre. The con- stant 14" has been added to 5^. TABLE VI. gives the principal perturbations of the longitude produced by Saturn, namely, 18".552sin (S— N) — 0 .141 sin 2 (S—N) — 0.012 sin 3^—^) + (const. = 19".000) TABLE VII. gives the principal perturbations of the longitude produced by Jupiter, namely, 34".121sin (J—N) • 0.011sin2(t7— N) + (const. = 35".000) TABLE VIII. gives the term — 0".524cos(2S — N) + (const. = 0".GOO) TABLE IX. gives the terms - 0".058 sin S + 0".047 costf + (const. = 0".100) • TABLE X. gives the terms + 0".1GG sin (S — 2 N) + 0".43G cos (S — 2 N) + (const. = 0".500) TABLE XI. gives the terms + 0".783 sin (2 / — N) — 0".1G4 cos (2J — N) + (const. =: 1'MOO) TABLE XII. gives the terms — 0".101 sin J + 0".097 cos J + (const. = 0".200) TABLE XIII. gives the terms + 0".32G sin (J—2N) + 0".297 cos (J — 2 N) + (const. = 0".500) TABLE XIV. will be more easily understood after we have explained the table of equation of the centre. TABLE XV. is composed of the four following parts : 1. The equation of the centre in the undisturbed ellipse of 1850.0, or, 80 TABLES OF NEPTUNE. + 2551-.117 sin I — 2403".35Scos + 1.163 sin 2 I — 18 .580 cos 2 I 0.088 sin 3 1 — 0.104 cos 3 1 2. The change in the equation of the centre produced by the perturbations of the elements h and k during that revolution of the planet which commenced 1779, Jan. 4, and ends 1943, Oct. 15. This change is represented by 2 Me sin I — 2 M cos I, M and 8k being taken from the table on p. 39 for the times corresponding to the various values of I during the period in question. 3. The terms — 14" sin 7 -14" cos I — 3 sin 2 I — 3 cos 2 I introduced to destroy the effect of the constants added to the values of PsA, Pcl, Ps,2, and Pc.2 to render them positive. 4. The constant 3529", ? added to render all the numbers of the table positive. During the revolution to which Table XV. corresponds, the planet passed from 180° mean longitude, and returned to the same point in the heavens ; whence the table begins and ends with this value of I. But since the commencement of the table corresponds to the values of 7* and k in 1779, and the end to these values in 1943, they do not correspond with each other. The sum of the constants added to Tables V. to XV. inclusive is 1°, which has been subtracted from y in Table I. Table XIV. is formed by subtracting the values of M- and M during the revo- lution of Table XV. from the values of the same elements 164.78 years earlier or later. Or, we have APU= 2(&' — M-o) APC., = — 2(8# — Mo) M' and 8fr representing the values of M and Sk at any epoch, and &7i0 and <$/,•„ their values at that date of the period 1779-1943 when the planet had the same mean longitude as at the epoch in question. The sum of the sixteen quantities P^ sin I, Pcj cos 7, P,2 sin 2 7, P^ cos 2 7, 8v d to 9) , 7, y, and the equation of Table XV. will give the true distance of the planet from its ascending node, which we represent by u. TABLE XVI. gives the reduction to the ecliptic for the years 1800, 1900, and 2000, together with the change of the reduction for a century. The constant 60" has been added to render all the numbers of the table positive. TABLES OF NEPTUNE. gj The sum of u, 6, and the reduction to the ecliptic gives the true ecliptic longi- tude of the planet, referred to the mean equinox of the date. Tables of the radius vector. TABLE XVII. gives the values of -B.J + 150, and R^ + 100. The expressions for E^ and #cl are given on p. 40, § 19, and the units are those of the seventh place of decimals. Rsl + 150 must be multiplied by sinZ, and HC.I + 100 by cos I, and the products included in the perturbations of log r. TABLE XVIII. gives the principal terms of the perturbations of the logarithm of the radius vector produced by Uranus, as given on p. 41. The constant added is 209. TABLE XIX. gives the perturbations of the same element by Saturn, namely, 39 7 cos (S — N) + 4 cos 2 (S — N) + (const. = 400) TABLE XX. gives the perturbations of the same element by Jupiter, namely, 701 cos (J—N) + (const. = 700) The units of these tables are those of the seventh place of decimals. TABLE XXI. is formed of the four following quantities. 1. A constant formed by applying the necessary corrections to the logarithm of the mean distance. We have Mean motion, including its perturbations, 7864.935 Secular var. long, epoch, _j_ 21.443 Elliptic mean motion, 7843.492 To which corresponds log a = 1.4787334 Constants of perturbations of log r (p. 31), 5920 Negative of constants added to Tables XVIII.-XX., — 1309 Constant to be substituted for log a in expression for log radius vector, 1.4780105 2. The elliptic log r — log a, namely, + .0000078 -.0026857 cos I —.0025301 sin I — .0000014 cos 2 I — .0000235 sin 2 I 3. The effects of the perturbations of h, k and a during the same revolution to which Table XV. corresponds, represented by MSh MSk r-^r- Sin I — :r- COS Z+ 6 log «, sin 1" sin 1" M being the modulus of the common system of logarithms. 11 May, 1865. 82 TABLES OF NEPTUNE. 4. The terms — 150 sin I — 100 cos I introduced to destroy the effects of the constants added to Rsl and 7?cl. TABLE XXII. gives the values of B^ and Bcl (p. 40). The constant 0".30 has been added to each of these quantities to render them positive. TABLES XXIII. and XXIV. give the perturbations of the latitude produced by Saturn and Jupiter respectively, no constants being added. TABLE XXV. gives the values of log sin i, to be added to log sin u in order to obtain the elliptic latitude. They, as well as 6, have been obtained from the formulae sin i sin 0 —p + 8p + 0".30 sin i cos 6 =. q -f- &q — 0 .30 The values of ftp and 8q being taken from the table p. 39, and the corrections + 0".30 being applied to destroy the effect of the constants added to Bsl and Bcl. § 38. Elementary precepts for the iise of the tables. Express the date for which the position of Neptune is required, in years, months, and days of Greenwich mean time, according to the Gregorian Calendar. If the date is between 1800 and 1955 inclusive, enter Table I. with the year, or the first preceding year found therein, and take out the values of /, y, 6, and Arguments 1—9 inclusive. Note also the value of P. If the date is not between the above limits, enter as if the number of the century were 18. Enter Table II. with the excess of the actual year above that with which Table I. was entered, and with the month. Write the values of 7, y, 6, and the arguments under those from Table I. Multiply I' and 0', the former interpolated to the day of the month, by P of Table I., and write the units of the product under the hundredths of seconds of I and 0, paying attention to the algebraic signs. Enter Table III. with the day of the mouth, and write down I, &c., under the former values. If the date is without the limits 1800-1955, enter Table IV. with the century, write the principal quantities under their proper heads, as before ; multiply column "Fact. T" by the entire fraction of the century represented by the date, and column "Fact. T2" by the square of this fraction, and write the products under their proper heads. Add up all the partial values of I, y, 6, and the arguments thus obtained, attending to the algebraic signs of the products, subtracting from the arguments as many times 400 as possible, and we have the final values of those quantities. Enter Table V. with the final value of Arg. 1, and take from it the five quan- tities there found. Multiply the first four of them as follows, using logarithms or natural numbers as may be most convenient : PiA by sine of Z, P,..! by cosine of f, P,z by sine of 2 I, Pc.2 by cosine of 2 /. TABLES OF NEPTUNE. 83 But if the* date is earlier than 1779 or later than 1943, PsA and P^ must first be corrected from Table X1Y. Write these four products under each other, remembering that their algebraic signs will be the same as those of the sine and cosine of I and 2 I, unless the cor- rections make Psl or Pc.i negative. Write under them the fifth quantity, &V Enter Tables VI. to XIII. inclusive, with the arguments at the top of each. Take out the eight remaining values of &v. Enter Table XV. with Z, first reducing the minutes and seconds to decimals of a degree, and take out the corresponding equation by interpolation to second differences. Under these fourteen quantities write Z and y, add up the sixteen lines, and call the sum u. Under u write 0 ; enter Table XVI. with u (reduced to hundredths of a degree) as the side argument, and the year as the top argument, and take out the reduction to the ecliptic. Add it to u and 0, and the sum will be the heliocentric longitude of Neptune referred to the mean equinox and ecliptic of the date. Enter Table XVII. with argument 1, and take out the values of R^ and R^. If the date is previous to 1779 or subsequent to 1943, multiply the values of APsi and AP^ from Table XIV. by 10.53, and correct R^ and B^ as follows : Rsl by 10.53 APcA, Rc.i by — 10.53 AP,i, adding the units of these products to the last figures of R,.i and R^. Then multiply Rsl by sine of Z, Rcl by cosine of I, and write down the products with the algebraic sign of sine I and cos I respectively. Enter Tables XVIII. to XX. with their proper arguments, and write the results under the products thus found. Enter Table XXI. with the argument Z, and take out the corresponding number, the first two figures of which are at the top of each column. Write it so that the last figure (the seventh place of decimals) shall be under the last figures of the former numbers. The sum of the six numbers thus found will be the common logarithm of the radius vector of Neptune. Enter Table XXII. with argument 1, and take out S^ and B^. Multiply the former by sin Z and the latter by cos Z. Enter Tables XXIII. and XXIV. with their proper arguments, and take out the corresponding numbers, applying the proper algebraic signs. Take the sine of i from Table XXV., and multiply it by the sine of u (u having already been found). The sum of the five quantities thus found, each taken with its proper algebraic sign, will be the north latitude of Neptune above the plane of the ecliptic of the date. Thus we shall have the heliocentric co-ordinates of the planet. The computer can then pass to the geocentric place by the method which he prefers. If an ephemcris is wanted during a series of years, it will not be necessary to 84 TABLES OF NEPTUNE. take the arguments from Tables I.-IV. more than once in three or four, or even five, years. The intervals of computation are first to be chosen, and need not he less than 180 days for the heliocentric place. Then compute the values of I, y, 0, and the arguments for the first date of the series, and again for a date an integral number of intervals (not generally exceeding ten) later. The longitudes and arguments for the intermediate dates may then be found by continual addition of the differences for 180 days (if this is the interval) from the bottom of Table I. § 39. Examples of (lie use of the tables. As a first example, we will compute an ephemeris of the heliocentric positions of Neptune for the years 1865 to 18G8 inclusive. The intervals of computation will be 180 days, and we commence with the date 1864, Oct. 13, and end with 1869, March 21, between which are nine of the assumed intervals. We first compute the epochs and arguments for the extreme dates as follows : 1. FOR 1864, OCTOBER 13. I y 0 Arg. 1 2 Table II., 1864, Table III., Year 0, Oct., Fact. X 9, Table IV., Day 13, 5 40 58.30 1 38 19.86 .14 4 18.39 228 54 54.37 7.88 0.35 130 15 49.25 29.82 — .01 1.31 91.96 1.75 0.08 199.49 8.87 0.37 Epochs & Args. 1864, Oct. 13, 7 23 36.69 228 55 2.60 130 16 20.37 93.79 208.23 Arg. 3 4 5 6 7 8 9 Table II., 1864, Table III., Year 0, Oct., Table IV., Day 13, 243.86 23.47 1.03 5 19 1 206 10 0 193 93.9 7 48.8 0 2.2 250 25 1 287 1 For 1864, Oct. 13. 268.36 25 216 200 144.9 276 200 2. FOR 1869, MARCH 21. I y 0 Arg. 1 2 Table II., 1868, Table III., Year 1, March, Fact. X 8, Table IV., Day 21, 14 25 17.73 2 82 81.25 .19 7 10.64 228 55 30.no 12.23 0.57 130 18 28.26 46.25 — .01 2.18 101.30 2.72 0.13 244.11 12.!>s 0.61 For 1869, March 21, 17 4 59.81 228 55 49.19 130 19 16.68 104.15 257.70 Arg. 3 4 5 6 7 8 9 Table II., 1868, Table III., Year 1, March, Table IV., Day 21, 369.03 36.41 1.71 104 29 1 260 16 1 990 Qf\^ O «l_n •)•>•>..' 10 75.7 0 3.6 385 39 2 858 34 2 For 1869, March 21, 7.15 134 277 -):)s 33 2 26 389 TABLES OF NEPTUNE. 85 The epochs and arguments for the intermediate dates are now formed by suc- cessive additions of the change in 180 days, deduced from Table I. T, the fraction of a century after 1850, being 0.148, the first differences for 180 days, with the arguments, are found to be as follows : Also 1864, Oct. 13 1865, Apr. 11 1866, Apr. 6 1868, Sept. 22 1869, Mar. 21 o / // I 1 4 35.908 7 23 36.69 8 28 12.598 9 32 48.505 16 023.920 17 459.818 AZ --0012 1 435.908 1 435.907 1 435.905 1 435.898 y 5.177 22855 2.60 22855 7.777 228 55 18.131 2285544.013 228 55 49.189 0 19.590 130 16 20.37 1301639.960 130 16 59.550 130 18 57.093 130 19 16.684 Arg. 1 1.150 93.79 94.940 96.090 102.990 104.140 2 5.497 208.23 213.727 219.224 252.206 257.703 3 15.421 268.36 283.781 299.202 391.729 7.151 4 12.20 25. 37.2 49.4 122.6 134.8 5 6.7 216. 222.7 229.4 269.6 276.3 6 4.3 200. 204.3 208.6 234.4 238.7 7 32.03 144.9 176.93 208.96 1.14 33.17 8 16.6 276. 292.6 309.2 8.8 25.4 9 14.2 260. 274.2 288.4 373.6 387.8 ° / 0 / 0 1 0 / 0 / 21 1447 1656 19.6 32 1 3410 o O 0 0 0 I (in Dec. of dog.) 7.3935 8.4702 9.5468 16.0066 17.0833 LONGITUDE. // n n ff ff P.J 23.76 24.04 24.30 25.57 25.72 Pai 22.50 22.14 21.77 19.35 18.93 P., 4.75 4.67 4.59 4.02 3.92 A, 1.76 1.67 1.59 1.21 1.17 P,, sin I 3.06 3.54 4.03 7.05 7.55 J\ , cos / 22.32 21.90 21.47 18.60 18.09 I\,*m 21 1.21 1.36 1.50 2.13 2.20 PC* cos 2 I 1.70 1.60 1.51 1.03 0.96 SVi 11.15 11.49 11.83 13.79 14.12 Sv, 16.57 15.01 13.41 5.30 4.26 9®t 5.03 1.98 0.88 30.58 38.83 8vt 0.12 0.17 0.23 0.78 0.87 dVg, 0.07 0.07 0.08 0.13 0.14 3v6 0.06 0.05 0.04 0.04 0.05 dv1 1.80 1.53 1.15 0.95 1.35 3vs 0.26 0.29 0.31 0.28 0.25 dl\ 0.06 0.08 0.13 0.64 0.73 Tab. XV. 02359.17 0 24 53.01 0 25 47.59 0 31 29.74 0 32 29.03 I 7 23 36.69 8 28 12.60 9 32 48.50 16 023.92 17 459.81 y 22855 2.60 22855 7.78 228 55 12.96 228 55 44.01 228 55 49.19 u 236 43 41.87 237 49 12.46 238 54 45.62 245 28 58.97 246 34 47.43 0 130 16 20.37 130163996 130 16 59.55 130 18 57.09 130 19 16.68 Red. Eel. 14.23 15.01 1588 22.33 23.62 Longitude 7 016.47 8 6 7.43 912 1.05 154818.39 16 54 27.73 86 TABLES OF NEPTUNE. RADIUS VECTOR. -B..1 *u 22 155 24 158 26 163 41 176 44 178 R,A sin I R,.i cos I S log rt 5 log r, 8 log r, Prin. term 3 154 82 10 306 1.4750064 156 77 17 524 1.4749650 4 158 73 23 691 1.4749250 11 169 48 129 1894 1.4747074 13 170 44 154 1896 1.4746754 logr 1.4750679 1.4750427 1.4750199 1.4748825 1.4748581 LATITUDE. log sin M log sin i log sin /90 5..: -BC.I 7?,! sin Z .fic , cos Z *& »A A 9.922246 8.492852 8.415098 // 0.47 0.01 + 0.05 + 0.01 + 0.28 — 0.54 — 1 29 25.02 9.927565 8.492842 8.420407 0.46 0.00 + 0.06 0.00 + 0.26 — 0.56 — 13031.03 9.932667 8.492831 8.425498 0.45 0.00 + oV 0.00 + 0.24 — 0.55 — 13135.09 9.958964 8.492764 8.451728 0.38 0.00 + 0.10 0.00 + 0.08 + 0.12 — 13717.28 9.962660 8.492753 8.455413 n 0.37 0.00 + 0.11 0.00 + 0.05 + 0.25 — 138 7.04 Latitude - 1 29 25.22 -13031.27 — 13135.33 — 13716.98 — 138 6.63 Inserting the results for the five middle dates, the computations of which have been omitted in printing, for want of space, we have the following heliocentric ephemeris of Neptune : Dale. Longitude (mean equinox of date). Logarithm of radius vector. Latitude. 01 II O ' It 18C4, Oct. 13, 7 0 16.47 1.4750679 — 1 29 25.22 1865, Apr. 11, 8 6 7.43 1.4750427 — 1 30 31. '-'7 Oct. 8, 9 12 1.05 1.4750199 — 1 31 35.:;:: 1866, Apr. Q, 10 17 57.51 1.4749986 — 1 3237.:;<» Oct. 3, 11 23 56.84 1.4749778 — 13337.41 1867, Apr. 1, 12 29 58.92 1.4749567 — 1 3435.41 Sept. 28, 13 36 3.52 1. 4749:542 -1 3531.38 1868, Mar. 26, 14 42 10.14 1.4749097 — 1 8625.26 Sept. 22, 15 48 18.39 1.4748825 — 1 37 16.98 1869, Mar. 21, 16 54 27.73 1.4748531 - 1 38 6.63 These co-ordinates being interpolated to every ten days, and corrected for nutation, the geocentric co-ordinates may then be computed and corrected for aberration in the usual way. TABLES OF NEPTUNE. 87 As another example, let us compute the heliocentric position of Neptune for Greenwich mean noon of 1795, May 9, the epoch of the normal place derived from Lalande's two observations. I / 9 Arg. 1 Arg. 2 Of ff Table I., 1892, 66 51 12.69 228 5C 48.26 130 34 22.60 157.30 111.85 Table II., 3' May, 71623.32 0 C 35.01 0 212.33 7.77 37.13 , 2 XV .13 — .01 Table III., Day 9, 0 252.26 0.23 0.87 0.05 0.24 Table IV., 1700, 141 31 19.97 359 42 21.53 358 53 55.63 166.69 85.00 Fact. T X -9536, + 45.60 f6.58 —8.75 — .05 — .36 Fact. T' X -91, + 0.22 0 0 + .01 -.02 1795, May 9, 215 42 34.19 228 42 51.61 129 30 22.67 331.77 233.84 21 = = 71.25 I = 215.7095 Arg. 3 4 5 6 7 8 9 Table I., 1892, 320.05 298 1? 56 38 314.2 394 246 Table II., 3" May, 104.18 82 L 15 29 216.6 112 96 Table III., Day 9. 0.68 1 0 0 1.4 1 1 Table IV., 1700, 70.66 327 2^ [2 328 298.6 228 313 Fact. T X .9536, + 0.12 \ 0 —1 + 0.2 0 0 1795, May 9, 95.69 307 ' '3 394 31.0 335 256 Longitude. Radius vector. Latitude. // u P.,- 16.69 R,i 242 Bal 0.39 PC, 0.38 Bcl 77 ^c.i 0.73 P., 5.16 PC., 1.97 P.., sin / — 9.74 K,A sin I — 141 log sin u 9.998700 Pclcos 1 — 0.31 BcA cos I — 63 log sin i 8.494395 P.'2 sin 2 I + 4.90 drl 234 log sin fa 8.493095 Pc2cos2/ +0.63 Sr, 60 Svl 24.08 8v, 9.48 dv, 69 05 Sr3 Prin. term 747 1.4816441 ff 7?,, sin 1 —0.22 B'cl cos 1 — 0.59 Ut/3 Ui/.VtJ <5u4 0.54 Sv,, 0.07 logr 1.4817278 '*,3, —0.06 <5/32 — 0.46 5v6 0.92 /?„ +147 0.82 Svi 1.32 <5u8 0.34 Latitude + 1 46 59.49 to, 0.06 Eq. Cent. 1 7 1.63 • I 2154234.19 y 228 42 51.61 u 8534 8.77 0 129 30 22.67 Ecd. Ecliptic 52.26 Long. (Mean Eq.) 215 5 23.70 Nutation - 15.90 Long. (True Eq.) 215 5 7.80 *~ 88 TABLES OF NEPTUNE. TABLE I. EPOCHS AND ARGUMENTS FOR THE BEGINNING OF EACH FOURTH YEAR FROM 1800 to 1952. Year. P I y e 1 1800 25 225 51 36.90 228 43 40.52 129 33 27.21 342.62 1804 24 234 35 57.56 228 44 22.73 129 36 5.97 35f.95 1808 23 243 20 18.15 228 45 04.92 129 38 44.75 361.28 1812 22 252 4 38.66 228 45 47.10 129 41 23.54 370.62 1816 21 260 48 59.10 228 46 29.27 129 44 2.35 379.95 1820 20 269 33 19.46 228 47 11.42 129 46 41.18 389.28 1824 19 278 17 39.74 228 47 53.56 129 49 20.02 39S.62 1828 18 287 1 59.94 228 48 35.69 129 51 58.88 7.95 1832 17 295 46 20.07 228 49 17.81 129 54 37.75 17.29 1836 16 304 30 40.12 228 49 59.92 129 57 16.64 26.62 1840 15 313 15 00.09 228 50 42.02 129 59 55.54 35.95 1844 14 321 59 19.98 228 51 24.11 130 2 34.45 45.29 1848 13 330 43 39.80 228 52 6.18 130 5 13.38 54.02 1852 12 339 27 59.54 228 52 48.24 130 7 52.33 63.96 1856 11 348 12 19.20 228 53 30.30 130 10 31.29 73.29 1860 10 356 56 38.79 228 54 12.34 130 13 10.26 82.03 1864 9 5 40 58.30 228 54 54.37 1-30 15 49.25 91.96 1868 8 14 25 17.73 228 55 36.39 130 18 28.26 101.30 1872 7 23 9 37.08 228 56 18.40 130 21 7.28 110.63 1876 6 31 53 56.36 228 57 0.40 130 23 46.31 119.96 1880 5 40 38 15.56 228 57 42.39 130 26 25.35 • 129.30 1884 4 49 22 34.68 228 58 24.36 130 29 4.42 138.63 1888 3 58 6 53.72 228 59 6.32 130 31 43.50 147.97 1892 2 66 51 12.69 228 59 48.26 130 34 22.60 157.30 1896 1 75 35 31.58 229 0 30.20 130 37 1.71 166.64 1900 0 84 19 28.87 229 1 12.09 130 39 40.75 175.97 1904 — 1 93 3 47.60 229 1 54.01 130 42 19.89 185.30 1908 — 2 101 48 6.26 229 2 35.92 130 44 59.04 194.64 1912 — 3 110 32 24.84 229 3 17.82 130 47 38.20 203.97 1916 — 4 119 16 43.35 229 3 59.71 130 50 17.38 213.31 1920 — 5 128 1 1.78 229 4 41.58 130 52 56.58 222.64 1924 — 6 136 45 20.13 229 5 23.44 130 55 35.80 231.98 1928 — 7 145 29 38.40 229 6 5.29 130 58 15.02 241.31 1932 — 8 154 13 56.60 229 6 47.14 131 0 54.26 250.65 1936 9 162 58 14.72 229 7 28.99 131 3 33.51 259.98 1940 — 10 171 42 32.77 229 8 10.80 131 6 12.77 269.32 1944 — 11 180 26 50.73 229 8 52.61 131 8 52.06 L'TS.65 1948 — 12 189 11 8.62 229 9 34.41 131 11 31.35 287.99 1952 — 13 197 55 26.43 229 10 16.20 131 14 10.66 291.0-2, O / " H ft ZA(1*» 1 4 35.943 5.182 19.583 1.150 Fact. T — 0.237 — 0.033 + 0.044 0.0 A (180) — 0.0012 — 0.0002 + 0.0002 0 TABLES OF NEPTUNE. 89 TABLE I. EPOCHS AND ARGUMENTS FOR THE BEGINNING OF EACH FOURTH YEAR FROM 1800 TO 1952 (Continued). Year. 2 3 4 5 6 7 8 9 1800 285.66 241.09 22 137 35 333.1 92 390 1804 330.27 366.26 121 191 70 193.2 227 105 1808 374.88 91.44 220 245 104 53.2 362 221 1812 19.49 216.61 319 300 139 313.3 97 336 1816 64.10 341.78 18 354 174 173.3 232 52 1820 108.71 66.96 117 8 209 33.4 367 167 1824 153.32 192.13 216 63 244 293.4 101 283 1828 197.94 317.31 315 117 279 153.5 236 398 1832 242.55 42.48 14 171 314 13.5 371 114 1836 287.17 167.65 113 226 349 273.5 106 229 1840 331.78 292.82 212 280 384 133.6 241 345 1844 376.40 18.00 310 334 19 393.6 376 60 1848 21.02 143.17 9 388 54 253.7 111 176 1852 65.64 268.34 108 43 88 113.7 245 291 1856 110.25 393.51 207 97 123 373.8 380 6 1860 154.87 118.68 306 151 158 233.8 115 122 1864 199.49 243.86 5 206 193 93.9 250 237 1868 244.16 369.03 104 260 228 353.9 385 353 1872 288.73 94.20 203 314 263 214.0 120 68 1876 333.35 219.37 302 369 298 74.0 255 184 1880 377.98 344.54 1 23 333 334.0 390 299 1884 22.60 69.71 100 77 368 194.1 125 15 1888 67.22 194.88 199 132 3 54.1 259 130 1892 111.85 320.05 298 186 38 314.2 394 246 1896 156.47 45.22 397 240 72 174.2 129 361 1900 201.06 170.29 96 295 107 34.3 264 77 1904 245.69 295.46 195 349 142 294.3 399 192 1908 290.32 20.63 294 3 177 154.4 134 308 1912 334.94 145.80 393 58 212 14.4 269 23 1916 379.57 270.97 92 112 247 274.5 4 138 1920 24.20 396.14 191 166 282 134.5 138 254 1924 68.82 121.30 290 221 317 394.6 273 369 1928 113.45 246.47 389 275 352 254.6 8 85 1932 158.08 371.64 88 330 387 114.7 143 200 1936 202.72 96.81 187 384 22 374.7 278 316 1940 247.35 221.97 286 38 57 234.8 13 31 1944 291.98 347.14 385 92 92 94.8 148 147 1948 336.61 72.31 84 147 126 354.9 283 262 1952 381.25 197.47 182 201 162 214.9 17 378 A<" i_M180l 5.497 15.421 12.20 6.7 4.3 32.03 16.6 14.2 Fact. T + .001 0 0 0 0 0 0 0 A(180) 0 0 0 0 0 0 0 0 12 Hay, 1863. 90 TABLES OP NEPTUNE. TABLE II. REDUCTION OF THE EPOCHS AND ARGUMENTS TO THE FIRST DAT OF EACH MONTH IN A CYCLE OF FOUR YEARS. I V y 0 ff 1 Year 0, O I II ft t ft Jan. 1, 0 0 0.00 0.00 0.00 0 00.00 0.00 0.00 Feb. 1, 0 11 7.50 0.16 0.89 0 3.37 — 0.01 0.20 Mar. 1, 0 21 31.94 0.32 1.72 0 6.53 — 0.01 0.38 Apr. 1, May 1, 0 32 39.44 0 43 25.41 0.48 0.64 2.61 3.48 0 9.90 0 13.17 '—0.02 — 0.03 0.58 0.77 June 1, 0 54 32.92 0.80 4.37 0 16.54 — 0.04 0.97 July 1, 1 5 18.89 0.96 5.23 0 19.81 — 0.05 1.16 Aug. 1, 1 16 26.39 1.12 6.12 0 23.18 — 0.05 1.36 Sept. 1, 1 27 33,89 1.29 7.01 0 26.55 — 0.06 1.56 Oct. 1, 1 38 19.86 1.45 7.88 0 29.82 — 0.07 1.75 Nov. 1, 1 49 27.37 1.61 8.77 0 33.19 — 0.08 1.95 Dec. 1, 2 0 13.34 1.77 9.64 0 36.46 — 0.08 2.14 Yearl, Jan. 1, 2 11 20.84 1.93 10.53 0 39.83 — 0.09 2.34 Feb. 1, 2 22 28.34 2.09 11.42 0 43.20 — 0.10 2.54 Mar. 1, 2 32 31.25 2.25 12.23 0 46.25 — 0.11 2.72 Apr. 1, 2 43 38.75 2.41 13.12 0 49.62 — 0.11 2.U1 May 1, 2 54 24.72 2.57 13.98 0 52.89 — 0.12 3.10 June 1, 3 5 32.22 2.73 14.87 0 56.26 — 0.13 3.30 July 1, 3 16 18.19 2.89 15.74 0 59.53 — 0.14 3.49 Aug. 1, 3 27 25.70 3.05 16.63 1 2.90 — 0.14 3.09 Sept. 1, 3 38 33.20 3.21 17.52 1 6.28 — 0.15 8.89 Oct. 1, 3 49 19.17 3.37 18.39 1 9.54 — 0.16 4.08 Nov. 1, 4 0 26.67 3.53 19.28 1 12.92 — 0.17 4.28 Dec. 1, 4 11 12.64 3.69 20.15 1 16.18 — 0.17 4.47 Year 2, Jan. 1, 4 22 20.15 3.85 21.04 1 19.56 — 0.18 4.67 Feb. 1, 4 33 27.65 4.01 21.93 1 22.93 — 0.19 4.87 Mar. 1, 4 43 30.55 4.17 22.74 1 25.98 — 0.20 5.05 Apr. 1, 4 54 38.06 4.33 23.63 1 29.35 — 0.20 5.24 May 1, 5 5 24.03 4.49 24.49 1 32.62 — 0.21 5.44 June 1, 5 16 31.53 4.65 25.38 1 35.99 — 0.22 5.63 July 1, 5 27 17.50 4.81 26.25 1 39.26 — 0.23 5.83 Aug. 1, 5 38 25.00 4.97 27.14 1 42.63 — 0.23 6.02 Sept. 1, 5 49 32.50 5.13 28.03 1 46.00 — 0.24 6.22 Oct. 1, 6 0 18.47 5.29 28.90 1 49.26 — 0.25 6.41 Nov. 1, 6 11 25.97 5.45 29.79 1 52.64 — 0.26 6.G1 Dec. 1, 6 22 11.94 5.61 30.66 1 55.90 — 0.26 6.80 Year 3, Jan. 1, 6 33 19.44 5.77 31.55 1 59.27 — 0.27 7.00 Feb. 1, 6 44 26.95 5.93 32.44 2 2.64 — 0.28 7.20 Mar. 1, 6 54 29.85 6.09 33.25 2 5.69 — 0.29 7.38 Apr. 1, 7 5 37.35 6.25 34.14 2 9.06 — 0.29 7.58 May 1, 7 16 23.32 6.41 35.00 2 12.33 — 0.30 7.77 June 1, 7 27 30.82 6.57 35.80 2 15.70 — 0.31 7.97 July 1, 7 38 16.79 6.73 36.77 2 18.97 — 0.32 8.16 Aug. 1, 7 49 24.29 6.89 37.66 2 22.34 — 0.32 8.36 Sept. 1, 8 0 31.80 7.05 38.55 2 25.72 — 0.83 8.55 Oct. 1, 8 11 17.76 7.21 39.40 2 28.98 — 0.34 8.75 Nov. 1, 8 22 25.27 7.37 40.30 2 32.36 — 0.34 8.94 Dec. 1, 8 33 11.24 7.53 41.17 2 35.62 — 0.35 9.14 Columns V and tf interpolated to the day of the month must be multiplied by the integer, P, of Table I. (not interpolated), and the units of the product added to the hundred ths of seconds of I. TABLES OF NEPTUNE. 91 TABLE II. REDUCTION OF THE EPOCHS AND ARGUMENTS TO THE FIRST DAT OF EACH MONTH IN A CYCLE OF FOUR YEARS (Continued). 2 3 4 5 6 7 8 9 Year 0, Jan. 1, 0.00 0.00 0 0 0 0.0 0 0 Feb. 1, 0.95 2.66 2 1 1 5.5 3 2 Mar. 1, 1.83 5.14 4- 2 1 10.7 6 5 Apr. 1, 2.78 7.80 6 3 2 16.2 8 7 May 1, 3.70 10.37 8 4 3 21.6 11 10 Juno 1, 4.64 13.02 10 6 4 27.1 14 12 July 1, 5.56 15.59 12 7 4 32.4 17 14 Aug. 1, 6.50 18.25 14 8 5 37.9 20 17 Sept. 1, 7.45 20.90 16 9 6 43.5 22 19 Oct. 1, 8.37 23.47 19 10 7 48.8 25 22 Nov. 1, 9.31 26.13 21 11 7 54.3 28 24 Dec. 1, 10.23 28.70 23 12 8 59.7 31 26 Year 1, Jan. 1, 11.18 31.36 25 14 9 65.2 34 29 Feb. 1, 12.12 34.01 27 15 9 70.7 37 31 Mar. 1, 12.98 36.41 29 16 10 75.7 39 34 Apr. 1, 13.92 39.07 31 17 11 81.3 42 36 May 1, 14.84 41.64 33 18 12 86.6 45 38 June 1, 15.79 44.29 35 19 12 92.2 48 41 July 1, 16.70 46.86 37 20 13 97.5 50 43 Aug. 1, 17.65 49.52 39 22 14 103.0 53 46 Sept. 1, 18.51 52.18 41 23 15 108.5 56 48 Oct. 1, 19.51 54.75 43 24 15 113.9 59 51 Nov. 1, 20.46 57.40 45 25 16 119.4 62 53 Dec. 1, 21.38 59.97 47 26 17 124.7 65 55 Year 2, Jan. 1, 22.32 62.63 50 27 17 130.2 68 58 Feb. 1, 23.27 65.29 52 28 18 135.7 70 60 Mar. 1, 24.12 67.68 54 29 19 140.7 73 62 Apr. 1, 25.07 70.34 56 30 20 146.2 76 65 May 1, 25.99 72.91 58 32 20 151.6 79 67 Juno 1, 26.93 75.57 60 33 21 157.1 81 70 July 1, 27.85 78.14 62 34 22 162.4 84 72 Aug. 1, 28.80 8079 64 35 23 167.9 87 74 Sept. 1, 29.74 83.45 66 36 23 173.4 90 77 Oct. 1, 30.66 86.02 68 37 24 178.8 93 79 Nov. 1, 31.60 88.67 70 38 25 184.3 96 82 Dec. 1, 32.52 91.24 72 40 25 189.6 98 84 Year 3, Jan. 1, 33.47 93.90 74 41 26 195.1 101 87 Feb. 1, 34.42 96.56 76 42 27 200.7 104 89 Mar. 1, 35.27 98.96 78 43 28 205.7 107 91 Apr. 1, 36.22 101.61 80 44 28 211.2 110 94 May 1, 37.13 104.18 82 45 29 216.6 112 96 Juno 1, 38.08 106.84 84 46 30 222.1 115 98 July 1, 39.00 109.41 87 47 30 227.4 118 01 Aug. 1, 39.94 112.06 89 49 31 232.9 121 03 Sept. 1, 40.89 114.72 91 50 32 238.4 124 106 Oct. 1, 41.81 117.29 93 51 33 243.8 126 108 Nov. 1, 42.75 119.95 95 52 34 249.3 129 111 Dec. 1, 43.67 122.52 97 53 34 254.6 132 113 92 TABLES OF NEPTUNE. TABLE III. REDUCTION FROM THE FIRST TO SUBSEQUENT DAYS OF ANY MONTH. Days. I y e i 2 3 4 5 6 7 8 9 f H H H 1 0 0.00 0.00 0.00 0.00 0.00 0.00 0 0 0 0 0 0 0 2 0 21.53 0.03 0.11 0.01 0.03 0.09 0 0 0 0 o 0 0 3 0 43.06 0.06 0.22 0.01 0.06 0.17 0 0 0 0 4 0 0 4 1 4.60 0.09 0.33 0.02 0.09 _ 0.26 0 0 0 0 5 0 0 5 1 26.13 0.11 0.44 0.03 0.12 0.34 0 0 0 0.7 0 0 6 1 47.C6 0.14 0.54 0.03 0.15 0.43 0 0 0' 0.9 0 0 7 2 9.19 0.17 0.65 0.04 0.18 0.51 0 0 0 1 1 0 0 8 2 30.73 0.20 0.76 0.04 0.21 0.00 1 0 0 1 3 1 1 9 2 62.26 0.23 0.87 0.05 0.24 0.08 1 0 0 1. 4 1 1 10 3 13.79 0.26 0 .98 0.06 0.27 0.77 1 0 0 1. 0 1 1 11 3 35.32 0.29 1 09 0 .06 0.30 0.86 1 0 0 1 8 1 1 12 3 66.86 0.32 1 .20 0.07 0.34 0.94 1 0 0 2.0 1 1 13 4 18.39 0.35 1 .31 0 .08 0.37 1.03 1 0 0 2 2 1 1 14 4 39.92 0.37 1 .41 0 .08 0.40 1.11 1 0 0 0 3 1 1 15 6 1.45 0.40 1 .52 0.09 0.43 1.20 1 1 0 2_ 5 1 1 16 6 22.99 0.43 1.63 0 .10 0.46 1.28 1 1 0 27 1 1 17 644.52 0.46 1 .74 0 .10 0.49 1.37 1 1 0 2. 9 2 1 18 6 6.05 0.49 1.85 0 .11 0.52 1.46 1 1 0 3. 1 2 1 19 6 27.58 0.52 1 .96 0.12 0.56 1.54 1 1 0 3. 2 2 1 20 6 49.11 0.54 2 .07 0 .12 0.58 1.63 1 1 0 3. 4 2 1 21 7 10.65 0.57 2.18 0 .13 0.01 1.71 1 1 0 3. 6 2 2 22 7 32.18 0.60 2 .29 0 .13 0.64 1.80 1 1 1 3. 8 2 2 23 7 53.71 0.63 2 39 0 .14 0.07 1.88 2 1 1 3. 0 2 2 24 8 15.24 0.66 2 .50 0.15 0.70 1.97 2 1 1 4. 1 2 2 25 8 36.78 0.69 2 .61 0 .15 0.73 2.06 2 1 1 4. 3 2 2 26 8 58.31 0.72 2 .72 0 .16 0.76 2.14 2 1 1 4. 4 2 2 27 9 19.84 0.75 2 83 0 .17 0.79 2.23 2 1 1 4. 6 2 2 28 9 41.37 0.78 2 .94 0 .17 0.83 2.31 2 1 1 4. 8 3 2 29 10 2.91 0.80 3 .05 0 .18 0.86 2.40 2 1 1 4. 9 3 2 30 10 24.44 0.83 3 .16 0 .18 0.89 2.48 2 1 1 5. 1 3 2 31 10 45.97 0.86 3.26 0.19 0.92 2.57 2 1 1 5. 3 3 2 In January and February of 1700, 1800, and 1900, Table III. must be entered with a number of days 1 greater than the real day of the month. TABLE IV. CORRECTIONS FOR PAST AND FUTURE CENTURIES. 1600 Fact. T Fact. 7s 1700 Fact. T Fact. 7" 1900 Fact. T Fact. T2 O f ft f n 0 1 I' tr " a i >i It n i 283 1 52.88 + 94.09 + 1.03 141 31 19.97 + 47.82 + 0.24 2182751.97 — 48.17 +0.17 .V 359 24 35.91 -j- 14.05 0 359 42 21.53 + 6.90 0 01731.67 — 6.92 0 e 35748 0.68 —18.59 0 358 53 65.63 — 9.17 0 16 13.54 + 9.19 0 Arg. 1 333.41 —0.08 + 0.01 100.69 — 0.05 + 0.01 233.35 + 0.02 —0.10 2 170.36 —0.69 — 0.08 85.00 — 0.38 — 0.02 315.40 + 0.46 -+(1.111; 8 141.19 +0.22 + 0.04 70.66 + 0.13 0.00 329.20 — 0.17 0 4 255. — 2 0 327. — 1 0 74. 0 0 5 85. —1 0 242. 0 0 158. 0 0 C 256. _1. 0 328. — 1 0 72. + 1. 0 7 196.9 -1-0.5 0 208.0 + 0.2 0 101.2 — 0.4 0 8 55. 0 0 228. 0 0 172. 0 0 9 227. 0 0 313. 0 0 87. 0 TABLES OF NEPTUNE. 93 TABLE. V. VI. VII. Arg. 1 2 3 P..I Diff. Pa Diff. /YJ PC.* d,, Diff. j Diff. *b Diff. II „ It n ;/ it // „ « n „ // 0 • 0.38 13.22 0.54 2.84 13.85 19.00 35.00 1 0.36 O.O2 13.49 0.27 0.54 2.92 13.33 0.52 19.29 0.29 35.54 o-54 2 0.35 0.01 13.76 0.27 0.53 3.00 12.80 0.53 19.57 0.28 36.07 0.53 3 0.34 O.OI 14.03 0.27 0.53 3.08 12.28 0.52 19.86 0.29 36.61 0.54 4 0.33 O.OI 14.30 0.27 0.53 3.16 11.76 0.52 20.14 0.28 37.14 0.53 0.00 0.27 0.51 0.29 0.54 5 0.33 14.57 0.54 3.25 11.25 20.43 37.68 6 0.33 o.oo 14.84 0.27 0.54 3.33 10.74 0.51 20.72 0.29 38.21 0.53 7 0.34 O.OI 15.11 0.27 0.55 3.41 10.24 0.50 21.00 0.28 38.75 0.54 8 0.34 o.oo 15.38 0.27 0.56 3.50 9.74 0.50 21.29 0.29 39.28 0.53 9 0.36 0.02 15.66 0.28 0.58 3.58 9.25 0.49" 21.57 0.28 39.81 0.53 0.02 0.27 0.49 0.28 0.53 10 0.38 15.93 0.59 3.66 8.76 21.85 40.34 11 0.40 O.O2 16.21 0.28 0.61 3.74 8.29 0.47 22.14 0.29 40.87 °'53 12 0.43 0.03 16.49 0.28 0.04 3.83 7.83 0.46 22.42 0.28 41.39 0.52 13 0.46 0.03 10.76 0.27 0.66 3.91 7.38 0.45 22.70 0.28 41.92 0.53 14 0.50 0.04 17.04 0.28 0.69 3.99 6.94 0.44 22.98 0.28 42.44 0.52 0.05 0.28 0.43 0.28 °-53 15 0.55 17.32 0.72 4.07 6.51 23.26 42.97 16 0.60 0.05 17.60 0.28 0.76 4.15 6.09 0.42 23.54 0.28 43.49 0.52 17 0.06 0.06 17.88 0.28 0.80 4.23 5.69 o 40 23.81 0.27 44.01 0.52 18 0.73 0.07 18.17 0.29 0.84 4.31 5.30 0.39 24.09 0.28 44.53 0.52 19 0.81 0.08 18.45 0.28 0.88 4.39 4.93 0.37 24.37 0.28 45.04 0.51 0.08 0.29 0.36 0.27 0.51 20 0.89 18.74 0.93 4.46 4.57 24.64 45.55 21 0.98 0.09 19.02 0.28 0.97 4.54 4.22 0.35 24.91 0.27 40.06 0.51 22 1.08 0. 10 19.31 0.29 1.03 4.61 3.89 o-33 25.18 0.27 •46.57 0.51 23 1.19 0. II 19.59 0.28 1.08 4.68 3.58 0.31 25.45 0.27 47.07 0.50 24 1.30 0. II 19.88 0.29 1.14 4.76 3.28 0.30 25.72 0.27 47.67 0.50 0.13 0.28 0.28 0.27 0.50 25 1.43 20.16 1.20 4.83 3.00 25.99 48.07 2fi 1.56 0.13 20.44- 0.28 1.27 4.89 2.73 0.27 26.25 0.26 48.56 0.49 27 1.70 0.14 20.73 0.29 1.34 4.96 2.48 0.25 26.52 0.27 49.05 0.49 28 1.88 o.i 6 21.01 0.28 1.41 5.02 2.25 0.23 26.78 0.26 49.54 0.49 29 2.02 o. 1 6 21.29 0.28 1.49 5.08 2.03 O.22 27.04 0.26 50.02 0.48 0.17 0.28 O.2I 0.26 0.48 30 2.19 21.57 1.56 5.14 1.82 27.30 50.50 31 2.38 0.19 21.84 0.27 1.64 5.20 1.63 O.I9 27.55 0.25 50.97 0.47 32 2.57 0.19 22.11 0.27 1.73 5.25 1.46 0.17 27.81 0.26 51.44 0.47 33 2.77 O.20 22.38 0.27 1.81 5.30 1.30 o.i 6 28.06 0.25 51.91 0.47 34 2.98 O. 21 22.66 0.27 1.90 5.34 1.16 0.14 28.31 0.25 52.38 0.47 0.23 0.26 0. 12 0.25 0.46 35 3.21 22.91 1.99 5.38 1.04 28.56 62.84 86 3.44 0.23 23.17 0.26 2.09 5.42 0.93 O. II 28.80 0.24 63.29 0.45 37 3.08 0.24 23.42 0.25 2.18 5.45 0.84 0.09 29.04 0.24 53.74 0.45 38 3.93 0.25 23.07 0.25 2.28 5.48 0.70 0.08 29.28 0.24 54.18 0.44 39 4.19 0.26 23.92 0.25 2.38 5.51 0.69 0.07 29.52 0.24 64.63 0.45 0.27 0.24 0.05 0.24 0.44 40 4.46 24.16 2.48 5.53 0.64 29.76 65.07 41 4.74 0.28 24.39 0.23 2.58 5.54 0.60 0.04 29.99 0.23 55.50 0.43 42 5.03 0.29 24.62 0.23 2.69 5.56 0.58 O.O2 80.22 0.23 66.92 0.42 43 6.88 0.30 24.84 O.22 2.79 5.56 0.57 O.OI 30.45 0.23 50.34 0.42 44 5.64 0.31 25.05 0.21 2.90 5.56 0.57 O.OO 30.68 0.23 60.70 0.42 0.31 O.2O O.O2 O.22 0.41 45 5.95 25.25 3.00 5.56 0.59 30.90 67.17 40 6.28 0.33 25.45 O.2O 3 11 5.55 0.61 O.O2 31.12 O.22 57.57 0.40 47 G.G1 0.33 25.64 0.19 321 5.54 0.65 0.04 31.34 0.22 57.07 0.40 48 6.94 0.33 25.82 o.i 8 3 32 5.53 0.70 0.05 31.55 0.21 68.30 0.39 49 7.29 0.35 25.99 0.17 !!.42 5.51 0.77 O.07 31.76 O.2I 58.75 0.39 0.35 0.17 0.08 0.21 0.39 GO 7.64 20.16 3.52 5.48 0.85 31.97 59.14 94 TABLES OF NEPTUNE. TABLK. V. VI. VII. Arg. 1 2 3 P..I Diff. -Pe.1 Diff. P+ *••! <5t>j Diff. *, Diff. *• Diff. n n n « tr H // ft ft n // n 50 7.64 26.16 3.52 5.48 0.85 31.97 59.14 51 8.00 0.36 26.31 0.15 3.63 5.45 0.94 0.09 12.17 O.2O 59.52 0.38 62 8.36 0.36 26.45 0.14 3.73 5.41 1.03 0.09 32.38 O.2I 59. 89 0.37 53 54 8.73 9.11 0.37 0.38 26.59 26.71 0.14 0.12 3.83 3.92 5.37 5.33 1.11 1.26 O. II 0.12 82.68 32.77 O.20 o. 19 60.25 00.01 0.36 0.36 0.38 O. II 0.13 0.19 0.35 55 9.49 26.82 4.02 5.28 1.39 32.96 60.90 56 9.87 0.38 26.93 0. II 4.11 5.23 1.53 O.I4 33.15 0.19 61.30 0.34 57 58 10.26 10.65 0.39 0.39 27.02 27.10 0.09 0.08 4.20 4.29 5.17 5.11 1.67 1.83 O.I4 o.i 6 33.34 88.62 019 0.18 61.68 61.96 °-33 0.33 59 11.05 0.40 0.40 27.17 0.07 O.O6 4.38 5.04 2.00 0.17 o.i 8 33.70 o.i 8 0.17 62.29 °-33 0.32 60 11.45 27.23 4.40 4.97 2.18 33.87 62.01 61 11.85 0.40 27.28 0.05 4.55 4.90 2.37 0.19 34.04 0.17 62.91 0.30 62 12.25 0.40 27.32 0.04 4.62 4.82 2.56 0.19 34.21 0.17 68.22 0.31 63 12.05 0.40 27.34 O.O2 4.70 4.74 2.76 0.2O 34.37 o.i 6 68.62 0.30 64 13.06 0.41 27.36 O.02 4.76 4.65 2.97 O.2I 34.53 o. 1 6 63.81 0.29 0.41 0.00 O.2I o. 1 6 0.29 65 13.47 27.36 4.83 4.57 3.18 34.69 04.10 66 13.88 0.41 27.35 O.OI 4.89 4.48 3.40 0.22 34.84 0.15 64.38 0.28 67 14.29 0.41 27.33 0.01 4.94 4.39 3.63 0.23 34.99 0.15 64.66 0.27 68 14.70 0.41 27.29 0.04 5.00 4.29 3.87 0.24 35.14 0.15 04.91 0.26 69 15.10 0.40 27.25 0.04 5.04 4.20 4.11 O.24 35.28 o. 14 05.17 0.26 0.41 0.06 0.25 0.14 0.24 70 15.51 27.19 5.09 4.10 4.36 35.42 65.41 71 15.92 0.41 27.12 0.07 5.13 3.99 4.61 0.25 35.55 0.13 65.05 0.24 72 16.32 0.40 27.04 0.08 5.16 3.89 4.86 0.25 35.68 0.13 65.88 0.23 73 16.72 0.40 26.95 0.09 5.19 3.79 5.13 O.27 35.81 0.13 00.10 O.22 74 17.12 0.40 26.84 O. II 5.22 3.69 5.39 O.26 35.93 0. 12 66.32 O.22 0.39 0.12 0.27 O. II O.2I 75 17.51 26.72 5.24 3.58 5.66 36.04 66.53 76 17.90 . o-39 26.59 0.13 5.25 3.48 5.94 0.28 36.16 0. 12 66.72 O.I9 77 18.29 0.39 26.45 O.I4 5.20 3.37 6.21 0.27 30.27 0. II 60.92 O.2O 78 18.67 0.38 26.30 0.15 5.27 3.27 6.50 0.29 36.37 0. 10 67.11 o. 19 79 19.05 0.38 26.14 o.i 6 5.27 3.16 6.78 0.28 30.47 0. IO 67.28 0.17 0.37 o.ig 0.29 O. IO 0.17 80 19.42 25.96 5.27 3.05 7.07 30.57 67.45 81 19.78 0.36 25.78 0.18 5.26 2.95 7.36 0.29 86.68 0.09 67.01 o.i 6 82 20.14 0.36 25.58 0.10 5.25 2.85 7.65 0.29 30.75 0.09 07.70 0.15 83 20.49 0.35 25.37 0.21 5.23 2.74 7.94 0.29 30.83 0.08 07.91 0.15 84 20.84 o-3S 25.15 O.22 5.21 2.64 8.24 0.30 30.91 0.08 68.05 o. 14 0.34 O.22 0.30 0.07 0.13 85 21.18 24.93 5.18 2.54 8.54 36.98 68.18 86 21.51 0.33 24.69 O.24 5.15 2.45 8.83 0.29 37.05 0.07 68.80 0. 12 87 21.8:5 0.32 24.44 0.25 5.11 2.35 9.13 0.30 37.12 0.07 68.41 O. II 88 22.14 0.31 24.18 0.26 5.07 2.25 9.43 0.30 37.18 0.06 68.62 O.II 89 22.45 0.31 23.U1 0.27 5.02 2.16 9.73 o. 30 37.24 0.06 68.61 0.09 0.29 0.27 0.29 0.05 0.09 90 22.74 23.64 4.97 2.07 10.02 37.29 68.70 91 23.02 0.28 23.35 0.29 4.92 1.98 10.82 0.30 37.34 0.05 68.78 0.08 92 23.30 0.28 23.06 0.29 4.86 1.96 10.82 0.30 87.88 0.04 58.86 O.O7 93 23.50 0.26 22.75 0.31 4.80 1.82 10.92 0.30 37.42 0.04 08.91 O.o6 94 23.81 0.25 22.44 0.31 4.74 1.74 11.21 0.29 37.45 0.03 68.97 0.06 0.24 0.32 0.30 0.03 O.OJ 95 24.05 22.12 4.67 1.66 11.51 37.48 09.02 90 24.28 0.23 21.80 0.32 4.60 1.59 11.80 0.29 37.51 0.03 oo.no O.O4 97 24.50 O.22 21.47 0.33 4.53 1.53 12.10 0.30 37.53 O.O2 69.09 0.03 98 24.71 O.2I 21.13 0.34 4.45 1.46 12.38 0.28 87.66 O.O2 69.1 1 O.O2 99 21.91 O.2O 20.78 0-35 4.37 1.40 12.07 O.29 37.50 O.OI 09.12 O.OI 0.19 0.35 O.29 0.00 O.OO 100 86.10 20.43 4.28 1.35 12.96 37.56 69.12 TABLES OP NEPTUNE. 95 TABLE. V. VI. VII. Arg. 1 2 3 P.1 Diff. Pc.l Diff. PS.l -Pc.2 fe, Diff. rfi)2 Diff. *•. Diff. n // tl It n // It n It n II n 100 25.10 20.43 4.28 1.35 12.96 37.56 69.12 101 25.26 o. 1 6 20.08 °-35 4.20 1.30 13.24 0.28 37.57 O.OI 69.12 o.oo 102 25.42 o.i 6 19.72 0.36 4.11 1.25 13.52 0.28 37.56 O.OI 69.11 O.OI 108 25.57 0.15 19.35 0.37 4.02 1.21 13.79 0.27 37.56 o.oo 69.09 O.O2 104 25.70 0.13 18.98 0.37 3.93 1.17 14.08 0.29 87.54 O.O2 69.06 0.03 0.12 0.37 0.26 O.OI 0.04 105 25.82 18.61 3.84 1.14 14.34 37.63 69.02 106 25.92 O. IO 18.23 0.38 3.75 1.11 14.00 0.26 37.51 O.O2 68.97 0.05 107 20.02 O. IO 17.86 o-37 3.65 1.09 14.87 0.27 37.48 0.03 68.91 0.06 108 26.10 0.08 17.47 0.39 3.56 1.07 15.13 0.26 37.45 0.03 68.85 0.06 109 26.16 0.06 O.O6 17.09 0.38 0.38 3.46 1.05 15.38 0.25 0.25 37.42 0.03 O.O4 68.78 0.07 0.08 110 26.22 16.71 3.36 1.04 15.03 37.38 68.70 111 26.26 O.O4 16.32 0.39 3.27 1.04 15.87 0.24 37.33 O.O5 68.62 0.08 112 26.28 0.02 15.94 0.28 3.17 1.04 10.11 0.24 37.28 0.05 68.52 O. IO 113 26.30 0.02 15.56 0.38 3.07 1.04 16.34 0.23 37.23 0.05 68.41 O. II 114 20.29 O.OI 15.17 0.39 2.98 1.06 16.57 0.23 37.17 O.O6 68.30 O. II O.OI 0.38 0.23 O.O6 0. 12 115 26.28 14.79 2.88 1.07 16.80 37.11 68.18 110 20.25 0.03 14.41 0.38 2.78 1.09 17.02 0.22 37.05 O.O6 68.05 0.13 117 26.20 0.05 14.03 0.38 2.69 1.11 17.24 O.22 36.98 O.07 67.91 O.I4 118 26.15 0.05 13.65 0.38 2.60 1.14 17.44 O.2O 36.90 0.08 67.76 O.I5 119 20.08 0.07 13.27 0.38 2.51 1.18 17.65 O.2I 36.82 0.08 67.61 0.15 0.08 0.37 0.19 0.08 o.i 6 120 20.00 12.90 2.42 1.21 17.84 36.74 67.45 121 25.90 0. 10 12.53 0.37 2.34 1.26 18.03 O.I9 36.65 O.Og 67.28 0.17 122 25.79 0. II 12.17 0.36 2.26 1.30 18.22 o. 19 36.55 O. IO 67.11 0.17 128 25.07 0.12 11.81 0.36 2.18 1.35 18.40 0.18 36.46 0.09 66.92 0.19 124 25.54 0.13 11.45 o. 36 2.10 1.41 18.57 0.17 36.35 O. II 60.73 0.19 O.I4 0.35 0.17 O.I I O.2O 125 25.40 11.10 2.03 1.46 18.74 36.24 66.53 12(3 25.24 o.i 6 10.70 0.34 1.95 1.52 18.89 0.15 36.13 O. II 66.32 O.2I 127 25.07 0.17 10.42 0.34 1.89 1.59 19.05 o.i 6 36.02 o.i i 66.10 O.22 128 24.89 o.i 8 10.09 °-33 1.82 1.66 19.19 0.14 35.90 0.12 65.88 0.22 129 24.70 0.19 9.77 0.32 1.76 1.73 19.33 0.14 35.77 0.13 65.65 0.23 0.21 0.32 0.13 0. 12 O.24 130 24.49 9.45 1.70 1.80 19.46 35.65 65.41 131 24.28 O.2I 9.14 0.31 1.65 1.88 19.59 0.13 35.51 o. 14 65.17 O.24 132 24.05 0.23 8.84 0.30 1.60 1.96 19.70 O. II 35.38 0.13 64.91 O.26 133 23.82 0.23 8.55 0.29 1.55 2.04 19.82 0.12 35.24 O.I4 64.65 O.26 134 23.57 0.25 8.27 0.28 1.51- 2.12 19.92 C. 10 35.09 O.I5 64.38 0.27 O.26 0.27 0. IO 0.15 0.28 135 23.31 8.00 1.47 2.21 20.02 34.94 64.10 136 23.04 0.27 7.73 0.27 1.44 2.29 20.11 0.09 34.79 O.I5 63.81 O.29 137 22.77 0.27 7.48 0.25 1.41 2.38 20.19 0.08 34.63 o.i 6 63.52 0.29 138 22.49 0.28 7.23 0.25 1.39 2.47 20.27 o 08 34.47 o.i 6 63.22 0.30 139 22.19 0.30 7.00 0.23 1.37 2.56 20.34 O.O7 34.31 o.i 6 62.91 0.31 0.30 0.23 O.O6 0.17 0.30 140 21.89 6.77 1.36 2.65 20.40 34.14 62.61 141 21.58 O.JI 6.50 O.2I 1.35 2.74 20.46 O.o6 33.97 0.17 62.29 0.32 142 21.27 0.3! 6.36 O.2O 1.34 2.83 20.50 O.O4 33.79 0.18 61.96 0.33 143 20.95 0.32 6.17 0.19 1.34 2.92 20.54 O.O4 33.61 0.18 61.63 0.33 144 20.63 0.32 5.99 o.i 8 1.35 3.01 20.58 0.04 33.43 o. 18 61.30 0.33 0.34 0.17 O.O2 0.19 0-34 145 20.29 5.82 1.35 3.10 20.60 33.24 60.96 146 19.96 o-33 5.67 0.15 1.37 3.18 20.63 O.O3 33.05 0.19 60.61 0.35 147 19.01 0.35 5.53 0.14 1.39 3.27 20.64 O.OI 32.85 O.20 60.25 0.36 148 19.26 0.35 5.40 0.13 1.41 3.36 20.65 O.OI 32.66 O.I9 59.89 0.36 149 18.91 0.35 5.28 0.12 1.44 3.44 20.65 o.oo 32.45 O.2I 69.52 0.37 0.35 O. II o.oo O.2O 0.38 150 18.56 5.17 1.47 3.52 20.65 32.25 59.14 96 TABLES OF NEPTUNE. TABLE. V. VI. VII. Arg. 1 2 3 P..I Diff. Pc.1 Diff. p^ P^ <5», Diff. fo, Diff. *• Diff. // it n n If II // // // M It // 150 18.56 5.17 1.47 3.52 20.62 32.25 59.14 151 18.20 0.36 5.08 0.09 1.50 3.60 20.64 O.OI 32.04 O.2I 68.75 0.39 152 17.84 0.36 6.00 0.08 1.54 3.68 20.62 O.O2 31.83 0.21 58.36 0.39 153 17.47 0.37 4.93 0.07 1.59 3.76 20.59 0.03 31.02 O.ZI 57.97 0.39 154 17.10 o-37 4.87 0.06 1.63 3.83 20.56 0.03 31.40 0.22 67.57 0.40 0.36 0.04 O.O4 0.22 0.40 155 16.74 4.83 1.69 3.90 20.52 31.18 67.17 156 16.37 0.37 4.80 0.03 1.74 3.97 20.48 O.O4 30.95 0.23 56.76 0.41 157 16.00 °-37 4.79 O.OI 1.80 4.03 20.43 0.05 30.73 0.22 66.34 0.42 158 15.64 0.36 4.78 O.OI 1.85 4.09 20.37 O.o6 30.50 0.23 56.92 0.42 159 15.27 0.37 4.79 O.OI 1.92 4.15 20.31 O.O6 30.26 O.24 55.50 0.42 0.37 0.03 O.O7 0.23 0-44 160 14.90 4.82 1.98 4.21 20.24 30.03 55.06 161 14.54 0.36 4.85 0.03 2.05 4.2G 20.16 0.08 29.79 O.24 54.03 0.43 162 14.18 0.36 4.90 0.05 2.12 4.30 20.08 0.08 29.55 O.24 54.18 0.45 103 13.82 0.36 4.97 0.07 2.20 4.35 19.99 0.09 29.31 O.24 53.74 0.44 164 13.46 0.36 5.04 0.07 2.27 4.39 19.90 0.09 29.00 0.25 53.29 0.45 0.35 0.09 O. IO 0.25 0.45 165 13.11 5.13 2.35 4.42 19.80 28.81 62.84 166 12.76 °-35 5.23 0. 10 2.43 4.45 19.70 O. IO 28.56 0.25 52.38 0.46 107 12.42 0.34 5.34 0. II 2.51 4.48 19.59 O.I I 28.30 O.26 51.1U 0.47 168 12.08 0.34 5.46 0. 12 2.59 4.50 19.48 0. II 28.04 O.26 51.44 0.47 109 11.74 0.34 6.60 0.14 2.67 4.52 19.36 0.12 27.79 0.25 50.97 °-47 o-33 0.14 0. 12 0.27 0.47 170 11.41 5.74 2.75 4.53 19.24 27.62 50.50 171 11.09 0.32 5.90 o.i 6 2.83 4.54 19.11 0.13 27.26 O.26 50.02 0.48 172 10.77 0.32 6.07 0.17 2.92 4.54 18.98 0.13 27.00 O.26 49.64 0.48 173 10.46 0.3: 6.25 0.18 3.00 4.54 18.84 O.I4 26.73 0.27 49.05 0.49 174 10.16 o. 30 6.44 0.19 3.08 4.53 18.70 O.I4 26.46 0.27 48.56 0.49 0.29 0.21 0.1S 0.27 0.49 175 9.87 6.65 3.16 4.68 18.55 20.19 48.07 176 9.58 0.29 6.86 O.2I 3.25 4.51 18.40 O.I5 25.92 0.27 47.57 0.50 177 9.31 0.27 7.09 0.23 3.33 4.49 18.24 o.i 6 26.64 0.28 47.07 0.50 178 9.04 0.27 7.32 0.23 3.41 4.47 18.09 0.15 26.87 0.27 46.67 0.50 179 8.78 O.26 7.56 0.24 3.49 4.44 17.92 0.17 25.09 0.28 40.00 0.51 0.25 0.26 o.i 6 0.28 0.52 180 8.53 7.82 3.57 4.41 17.70 24.81 45.54 181 8.29 0.24 8.08 0.26 3.04 4.38 17.59 0.17 24.52 0.29 45.03 0.51 182 8.06 0.23 8.35 0.27 3.71 4.34 17.41 o.i 8 24.24 0.28 4-1.52 0.51 183 7.84 O. 22 8.62 0.27 3.79 4.30, 17.24 0.17 23.96 0.28 44.01 0.51 184 7.63 0.21 8.91 0.29 3.85 4.25 17.06 (5. 1 8 23.67 0.29 43.49 0.52 0.20 0.29 0.18 0.28 0.52 185 7.43 9.20 3.92 4.20 16.88 23.39 42.97 186 7.24 0.19 9.49 0.29 3.98 4.14 16.70 0.18 23.10 0.29 42.44 0.53 187 7.06 0.18 9.80 0.31 4.04 4.09 16.51 0.19 22.81 0.29 41.92 0.52 188 6.90 0.16 10.11 0.31 4.10 4.03 16.32 0.19 22.52 0.29 41.39 0.53 189 6.76 0.15 10.42 0.31 4.15 3.96 10.13 0.19 22.23 0.29 40.87 0.52 0.14 0.33 0.19 0.29 o-53 190 6.61 10.76 4.20 8.90 15.94 21.94 40.34 191 6.48 0.13 11.07 0.32 4.25 3.83 15.75 . O. IO f 21.65 0.29 39.81 o-53 192 6.36 O. II 11.40 0.33 4.29 3.76 15.55 0.20 21.36 0.29 39. 28 0.53 193 6.26 O. IO 11.74 0.34 4.33 3.69 15.36 0.19 21.06 0.30 38.75 0.53 194 6.17 0.09 12.08 0.34 4.36 3.61 15.16 O.2O 20.77 O.29 38.21 0.54 0.07 0.34 O.2O 0.30 °-53 195 6.10 12.42 4.39 3.64 14.96 20.47 37.68 196 6.03 0.07 12.76 0.34 4.42 3.46 14.76 O.2O 20.18 O.29 37.14 0.54 197 5.98 0.05 13.11 0.35 4.44 3.38 14.56 O.2O 19.89 O.29 36.61 0.53 198 5.94 0.04 13.46 0.35 4.46 3.30 14.36 O.2O 10.59 0.30 30.07 0.54 199 5.92 O.O1 13.80 0.34 4.48 3.22 14.16 O.2O 19.30 0.29 35.54 o-53 O.OI 0.36 O. 2O 0.30 0.54 200 5.91 14.16 4.49 3.13 13.96 19.00 35.00 TABLES OF NEPTUNE. 97 TABLE. V. VI. VII. Arg. 1 2 3 P..1 Diff. JVi Diff. f..2 Prt fv, Diff. iv, Diff. S*3 Diff. // n // If n II n /* „ n tl n 200 5.91 14.16 4.49 3.13 13.96 19.00 35.00 201 5.91 O.OO 14.51 0.35 4.49 3.05 13.76 O.2O 18.70 0.30 34.46 0.54 •2i>'2 5.92 O.OI 14.86 0.35 4.49 2.97 13.56 O.2O 18.41 0.29 33.113 0.53 203 5.95 0.03 15.21 0.35 4.49 2.88 13.36 O.2O 18.11 0.30 33.39 0.54 204 6.00 0.05 15.55 0.34 4.48 2.80 13.16 O.2O 17.82 0.29 32.86 0.53 0.06 0.35 0.19 0.29 0.54 205 6.06 15.90 4.47 2.72 12.97 17.53 32.32 206 6.12 0.06 16.25 0.35 4.45 2.64 12.77 O.2O 17.23 0.30 31.79 0.53 207 6.21 0.09 10.59 0.34 4.43 2.56 12.57 O.2O 16.94 0.29 31.25 0.54 208 6.30 0.09 16.93 0.34 4.41 2.48 12.38 O.I9 16.64 0.30 30.72 0.53 209 6.41 0. II 17.27 0.34 4.38 2.41 12.19 0.19 16.35 0.29 30.19 0.53 O.I2 0.33 0.19 0.29 °-53 210 G.'53 17.60 4.34 2.33 12.00 16.06 29.66 211 6.65 0.12 17.93 °-33 4.31 2.26 11.81 O.I9 15.77 0.29 29.13 0.53 212 6.80 O.I5 18.26 0.33 4.27 2.19 11.62 0.19 15.48 0.29 28.61 0.52 213 6.96 o.i 6 18.57 0.31 4.22 2.13 11.43 0.19 15.19 0.29 28.08 0.53 214 7.14 o.i 8 18.89 0.32 4.17 2.06 11.25 0.18 14.90 0.29 27.56 0.52 0.18 0.31 o.i 8 0.29 0.53 215 7.32 19.20 4.12 2.00 11.07 14.61 27.03 216 7.51 0.19 19.50 0.30 4.07 1.94 10.89 o.i 8 14.33 0.28 26.51 0.52 217 7.72 0.21 19.79 0.29 4.01 1.88 10.72 0.17 14.04 0.29 25.99 0.52 218 7.94 O.22 20.08 0.29 3.95 1.83 10.55 0.17 13.76 0.28 25.48 0.51 219 8.16 O.22 20.36 0.28 3.88 1.78 10.38 0.17 13.48 0.28 24.96 0.52 0.24 0.27 o.i 6 0.29 0.51 220 8.40 20.63 3.82 1.73 10.22 13.19 24.45 221 8.65 0.25 20.90 0.27 3.75 1.69 10.06 o.i 6 12.91 0.28 23.94 0.51 222 8.91 O.26 21.15 0.25 3.68 1.65 9.90 o.i 6 12.63 0.28 23.43 0.51 223 9.18 0.27 21.40 0.25 3.60 1.62 9.74 o.i 6 12.36 0.27 22.93 0.50 224 9.45 0.27 21.64 0.24 3.53 1.59 9.59 0.15 12.08 0.28 22.43 0.50 0.29 0.23 0.15 0.27 0.50 225 9.74 21.87 3.45 1.56 9.44 11.81 21.93 226 10.04 O.JO 22.08 0.21 3.37 1.54 9.30 0.14 11.54 0.27 21.44 0.49 227 10.34 o. 30 22.29 O.2I 3.29 1.52 0.16 0.14 11.27 0.27 20.95 0.49 228 10.65 0.3I 22.49 O.2O 3.22 1.50 9.03 0.13 11.00 0.27 20.46 0.49 229 10.97 0.32 22.67 o.i 8 3.14 1.49 8.90 0.13 10.74 0.26 19.98 0.48 0.33 0.18 0. 12 0.26 0.48 230 11.30 22.85 3.06 1.49 8.78 10.48 19.50 231 11.63 0.33 23.01 o.i 6 2.97 1.49 8.66 0.12 10.21 0.27 19.03 0.47 232 11.97 0.34 23.K! 0.15 2.89 1.49 8.54 0. 12 9.96 0.25 18.56 0.47 233 12.32 0.35 23.30 0.14 2.81 1.50 8.44 O.IO 9.70 0.26 18.09 0.47 234 12.67 0.35 23.42 O.I2 2.73 1.51 8.33 0. II 9.44 0.26 17.62 0.47 0.36 O.I2 0.09 0.25 0.46 235 13.03 23.54 2.65 1.53 8.24 9.19 17.16 230 13.39 0.36 23.64 O. IO 2.57 1.55 8.14 O.IO 8.94 0.25 16.71 0.45 237 13.76 0.37 23.73 0.09 2.49 1.58 8.06 0.08 8.69 0.25 16.26 0.45 238 14.12 0.36 23.81 0.08 2.42 1.60 7.97 0.09 8.45 6.24 15.82 0.44 239 14.50 0.38 23.87 O.O6 2.34 1.64 7.90 O.O7 8.21 0.24 15.37 0.45 0.37 O.O6 O.O7 0.24 0.43 240 14.87 23.93 2.27 1.68 7.83 7.97 14.94 241 15.25 0.38 23.96 0.03 2.20 1.72 7.77 O.O6 7.74 0.23 14.50 0.44 242 15.63 0.38 23.99 0.03 2.13 1.76 7.71 O.O6 7.50 0.24 14.08 0.42 243 16.01 0.38 24.00 O.OI 2.06 1.81 7.66 O.O5 7.27 0.23 13.66 0.42 244 16.39 0.38 24.00 O.OO 2.00 1.87 7.61 0.05 7.05 O.22 13.24 0.42 0.38 O.OI O.O4 0.23 0.41 245 16.77 23.99 1.93 1.92 7.57 6.82 12.83 246 17.16 0.39 23.96 0.03 1.88 1.98 7.54 0.03 6.60 O.22 12.43 0.40 247, 17.54 0.38 23.92 0.04 1.82 2.04 7.62 O.O2 6.38 0.22 12.03 0.40 248 17.92 0.38 23.86 0.06 1.77 2.11 7.50 0.02 6.17 O.2I 11.64 0.39 249 18.30 0.38 23.79 0.07 1.72 2.18 7.48 O.O2 5.96 O.2I 11.25 0.39 0.37 0.08 O.OO O.2I 0.39 250 18.67 23.71 1.67 2.25 7.48 5.75 10.86 13 May, 1865. 98 TABLES OF NEPTUNE. TABLE. V. VI. VII. Arg. 1 2 3 P..I Diff. Pc.1 Diff. P* PC., 6vl Diff. *t Diff. *ll Diff. n n ft n H H tt ff // tt // tt 250 18.67 23.71 1.67 2.25 7.48 5.75 10.80 251 19.05 °-38 23.62 0.09 1.63 2.32 7.47 O.OI 5.55 O.2O 10.48 0.38 252 19.42 0.37 23.51 O. II 1.59 2.40 7.48 O.OI 5.34 O.2I 10.11 0.37 253 19.78 0.36 23.39 0. 12 1.55 2.48 7.50 O.O2 5.15 O.I9 9.75 0.36 254 20.15 0.37 23.26 O.I3 1.52 2.56 7.52 O.O2 4.95 O.2O 9.39 0.36 0.36 O.IS O.O2 O.I9 o-35 255 20.51 23.11 1.60 2.64 7.54 4.76 9.04 256 20.86 °-35 22.96 0.15 1.48 2.72 7.58 O.O4 4.57 O.lg 8.70 o-34 257 21.21 0.35 22.78 o.i 8 1.40 2.81 7.61 O.O3 4.39 0.18 8.37 0.33 258 21.55 0.34 22.00 o.i 8 1.44 2.90 7.66 0.05 4.21 0.18 8.04 0.33 259 21.89 0.34 22.41 0.19 1.43 2.98 7.71 0.05 4.03 o.i 8 7.71 °-33 0.33 O.2O 0.06 0.17 0.32 260 22 22 22.21 1.43 3.07 7.77 3.86 7.39 201 22.55 0.33 21.99 O.22 1.43 3.16 7.84 O.O7 3.69 0.17 7.09 0.30 262 22.8(5 0.31 21.76 0.23 1.43 3.25 7.91 O.O7 3.53 o.i 6 6.78 0.31 263 23.17 0.31 21.52 0.24 1.44 3.33 7.99 0.08 3.37 • o. 1 6 6.48 0.30 264 23.47 0.30 21.27 0.2S 1.46' 3.42 8.08 O.Og 3.21 o.i 6 6.19 0.29 0.29 O.26 O.O^ 0.15 0.29 265 23.76 21.01 1.47 3.51 8.17 3.06 5.90 266 24.04 0.18 20.74 0.27 1.50 3.59 8.28 O. II 2.91 0.15 5.62 0.28 267 24.32 0.28 20.46 0.28 1.52 3.68 8.38 0. 10 2.76 0.15 5.35 0.27 238 24.58 0.26 20.17 0.29 1.56 3.76 8.50 0. 12 2. 02 0.14 5.09 0.26 269 24.83 0.25 19.87 0.30 1.59 3.85 8.62 0.12 2.49 0.13 4.83 0.26 0.25 0.30 O.I 2 0.14 0.24 270 25.08 19.57 1.63 3.93 8.74 2.35 4.59 271 25.31 0.23 19.25 0.32 1.68 4.01 8.88 0.14 2.23 0.12 4.35 0.24 272 25.53 O.22 18.93 0.32 1.72 4.08 9.02 0.14 2.10 0.13 4.12 0.23 273 25.74 O.2I 18.59 0.34 1.78 4.16 0.17 O.IS 1.98 0. 12 3.90 O.22 274 25.93 0.19 18.26 0.33 1.83 4.23 9.32 O.IS 1.87 0. II 3.08 0.22 O.I9 0.35 o.i 6 O. II O.2I 275 26.12 17.91 1.89 4.30 9.48 1.76 3.47 276 26.29 0.17 17.56 0-35- 1.96 4.36 9.65 0.17 1.65 0. II 3.27 O.2O 277 20.46 0.17 17.20 0.36 2.02 4.43 9.82 0.17 1.54 O. II 3.08 0.19 278 26.60 O.I4 16.84 0.36 2.09 4.49 10.00 o.i 8 1.45 0.09 2.89 0.19 279 26.74 O.I4 16.47 0.37 2.16 4.55 10.19 0.19 1.35 0. 10 2.72 0.17 0.13 0.38 0.19 0.09 O.I7 280 26.87 16.09 2.24 4.60 10.38 1.26 2.55 281 26.98 0.1 1 15.71 0.38 2.32 4.65 10.57 0.19 1.18 0.08 2.39 0.16 282 27.07 0.09 15.33 0.38 2.40 4.69 10.78 O.2I 1.10 0.08 2.24 0.15 283 27.16 0.09 14.94 0.39 2 48 4.73 10.98 O.2O 1.02 0.08 2.09 0.15 284 ' 27.23 0.07 14.55 0.39 2.57 4.77 11.20 O.22 0.95 0.07 1.95 0.14 O.O6 0.39 O.22 0.06 0.13 285 27.29 14.16 2.66 4.80 11.42 0.89 1.82 286 27.34 0.0S 13.77 o-39 2.75 4.83 11.64 O.22 0.83 0.06 1.70 0.12 287 27.37 0.03 13.37 0.40 2.84 4.85 11.87 0.23 0.77 0.06 1.59 O. II 288 27.38 0.01 12.97 0.40 2.93 4.87 12.10 0.23 0.71 0.06 1.48 O.I I 289 27.39 0.01 12.58 0.39 3.03 4.88 12.34 0.24 0.67 0.04 1.38 O. IO O.OI 0.40 0.25 0.05 0.08 290 27.38 12.18 3.12 4.89 12.59 0.62 1.30 291 27.35 0.03 11.78 0.40 3.21 4.90 12.84 0.25 0.58 0.04 1.22 O.oS 292 27.31 0.04 11.38 0.40 3.31 4.90 13.09 0.25 0.55 0.03 1.15 0.07 293 27.26 0.05 10.98 0.40 3.40 4.90 13.34 0.25 0.52 0.03 1.09 O.06 294 27.20 0.06 10.58 0.40 3.50 4.89 13.60 O.26 0.49 0.03 1.03 0.06 0.08 0.39 0.27 O.O2 0.05 295 27.12 10.19 3.59 4.87 13.87 0.47 0.98 296 27.03 0.09 9.80 0.39 3.69 4.85 14.13 0.26 0.46 O.OI 0.94 O.O4 297 20.92 O.I I 9.41 0.39 3.78 4.83 14.40 0.27 0.44 O.O2 0.91 0.03 298 26.80 0. 12 9.02 0.39 3.87 4.80 14.68 0.28 0.44 O.OO 0.89 O.O2 299 26.67 0.13 8.64 0.38 3.96 4.76 14.95 0.27 0.43 O.OI 0.88 O.OI 0.14 0.38 0.2g O.OI O.OO 300 26.53 8.26 4.06 4.73 15.23 0.44 0.88 TABLES OF NEPTUNE. 99 TABLE. V. VI. VII. Arg. 1 2 3 -P..! Diff. Pc.l Diff. P.3 P* 6vl Diff. Svt Diff. ivt Diff. It a II n tl n „ // n n » // 300 26.53 8.26 4.06 4.73 15.23 0.44 0.88 301 26.37 o.i 6 7.89 0.37 4.14 4.68 15.51 0.28 0.44 o.oo 0.88 o.oo 302 20.20 0.17 7.52 0.37 4.23 4.64 15.80 0.29 0.45 O.OI 0.89 O.OI 303 26.02 o.i 8 7.16 0.36 4.31 4.59 16.08 0.28 0.47 O.O2 0.91 O.O2 304 25.82 O.2O 6.80 0.36 4.40 4.43 16.37 0.29 0.49 O.O2 0.94 0.03 O. 20 0.35 0.28 0.03 O.O4 305 25.62 6.45 4.47 4.47 16.65 0.52 0.98 306 25.40 O.22 6.10 °-35 4.55 4.41 16.95 0.30 0.55 0.03 1.03 0.05 307 25.17 O.2J 5.76 0.34 4.62 4.34 17.24 0.29 0.58 0.03 1.09 O.o6 308 24.92 0.25 5.43 0.33 4.69 4.27 17.53 0.29 0.62 0.04 1.15 O.O6 309 24.67 0.25 5.11 0.32 4.76 4.20 17.82 0.29 0.66 O.O4 1.22 0.07 O.26 0.31 0.30 0.05 0.08 310 24.41 4.80 4.83 4.12 18.12 0.71 1.30 311 24.14 0.27 4.49 0.31 4.89 4.04 18.41 0.29 0.76 0.05 1.38 0.08 312 23.85 0.29 4.19 0.30 4.94 3.96 18.71 0.30 0.82 0.06 1.48 O. IO 313 23.56 0.29 3.90 0.29 5.00 3.87 19.00 0.29 0.88 O.O6 1.59 O. II 814 23.26 O.JO 3.62 0.28 5.05 3.78 19.29 0.29 0.95 O.O7 1.70 0. II 0.32 0.27 0.29 O.O7 0. 12 315 22.94 3.35 5.09 3.69 19.58 1.02 1.82 316 22.62 0.32 3.08 0.27 5.13 3.59 19.87 0.29 1.09 O.O7 1.95 0.13 317 22.29 0.33 2.83 0.25 5.17 3.50 20.16 0.29 1.17 0.08 2.09 0.14 318 21.95 0.34 2.59 0.24 5.20 3.40 20.45 0.29 1.25 0.08 2.24 O.I5 319 21.61 0.34 2.36 0.23 5.23 3.30 20.73 0.28 1.34 0.09 2.39 O.I5 0.36 O.22 0.29 0.09 0.16 320 21.25 2.14 5.25. 3.20 21.02 1.43 2.55 321 20.89 0.36 1.93 O.2I 5.27 3.10 21.29 0.27 1.53 O. IO 2.72 0.17 322 20.53 0.36 1.73 O.2O 5.28 2.99 21.57 0.28 1.63 O. IO 2.90 0.18 323 20.15 0.38 1.54 0.19 5.29 2.89 21.84 0.27 1.73 O. IO 3.09 0.19 321 19.78 0.37 1.36 0.18 5.30 2.78 22.12 0.28 1.84 O. II 3.28 0.19 0.39 o.i 6 0.26 0. 12 O.2O 325 19.39 1.20 5.29 2.68 22.38 1.96 3.48 326 19.00 0.39 1.04 o.i 6 5.29 2.57 22.65 0.27 2.07 O. II 3.70 O.22 327 18.61 0.39 0.90 0.14 5.28 2.46 22.91 0.26 2.19 0.12 3.92 0.22 328 18.22 0.39 0.77 °-'3 5.26 2.36 23.16 0.15 2.32 O.I3 4.14 O.22 «29 17.82 0.40 0.65 0. 12 5.24 2.25 23.41 0.25 2.45 0.13 4.37 0.23 0.41 O. II 0.25 0.13 O.24 330 17.41 0.54 5.22 2.15 23.66 2.58 4.61 331 17.01 0.40 0.45 0.09 5.19 2.05 23.90 0.24 2.72 0.14 4.85 O.24 332 16.60 0.41 0.36 0.09 6.15 1.95 24.13 0.23 2.86 O.I4 5.11 O.26 333 16.19 0.41 0.29 O.O7 5.12 1.85 24.36 0.23 3.01 O.I5 5.37 O.26 334 15.78 0.41 0.24 O.O5 5.07 1.75 24.58 O.22 3.16 O.I5 5.64 0.27 0.41 O.O5 O.22 O.IS 0.28 335 15.37 0.19 5.02 1.65 24.80 3.31 5.92 336 14.95 0.42 0.16 O.O3 4.97 1.56 25.00 0.20 3.47 0.16 6.21 0.29 337 14.54 0.41 0.13 0.03 4.92 1.47 25.21 O.2I 3.63 o.i 6 6.50 0.29 338 14.13 0.41 0.12 O.OI 4.85 1.38 25.40 O.I9 3.79 o.i 6 6.80 0.30 339 13.72 0.41 0.12 0 00 4.79 1.29 25.59 0.19 3.96 0.17 7.11 0.31 0.41 O.OI O.I? 0.17 0.30 340 13.31 0.13 4.72 1.21 25.76 4.13 7.41 341 12.90 0.41 0.1 6 0.03 4.65 1.13 25.93 0.17 4.30 0.17 7.73 0.32 342 12.49 0.41 0.19 0.03 4.57 1.05 26.09 o.i 6 4.48 0.18 8.06 0.33 343 12.09 0.40 0.24 0.05 4.49 0.98 26.24 0.15 4.66 o.i 8 8.39 0.33 344 11.69 0.40 0.30 0.06 4.41 0.91 26.39 0.15 4.85 0.19 8.72 0.33 0.40 0.07 0.13 0.19 0.34 345 11.29 0.37 4.32 0.85 26.52 6.04 9.06 346 10.89 0.40 0.46 0.09 4.24 0.79 26.65 0.13 5.23 0.19 9.41 °-35 347 10.50 0.39 0.55 0.09 4.15 0.73 26.76 0. II 5.42 0.19 9.77 o. 36 348 10.12 0.38 0.65 O. IO 4.05 0.68 26.86 O. IO 6.62 0.2O 10.13 0.36 349 9.73 0.39 0.77 O.I2 3.96 0.63 26.95 0.09 5.83 0.21 10.50 0.37 0.38 0. 12 0.08 O.2O 0.38 350 9.35 0.89 3.86 0.59 27.03 6.03 10.88 100 TABLES OF NEPTUNE. TABLE. V. VI. VII. Arg. 1 2 3 />,, Diff. -P..1 Diff. P., P« *, Diff. *, Diff. *. Diff. n n n It It It n n ,i n n n 350 9.35 0.89 3.86 0.59 27.03 6.03 10.88 351 8.98 0.37 1.02 0.13 3.77 0.55 27.09 O.O6 6.24 O.2I 11.20 0.38 352 8.62 0.36 1.17 0.15 3.66 0.52 27.15 O.O6 O.2I 11.66 0.40 353 8.26 0.36 1.32 0.15 3.56 0.49 27.20 0.05 6.6fl O.2I 12.05 0.39 354 7.90 0.36 1.48 o.i 6 8.46 0.47 27.23 0.03 6.88 O.22 12.45 0.40 0.34 0.18 0.03 O.22 0.40 355 7.56 1.66 3.36 0.45 27.26 7.10 12.85 356 7.22 0.34 1.83 0.17 3.26 0.43 27.27 O.OI 7.32 O.22 13.26 0.41 357 6.89 0.33 2.02 0.19 3.15 0.42 27.27 o.oo 7.55 0.23 13.I18 0.42 868 6.56 0.33 2.22 O.2O 3.05 0.42 27.25 O.02 7.78 0.23 14.10 0.42 359 6.25 0.31 2.42 O.2O 2.95 0.42 27.22 0.03 8.01 0.23 14.52 0.42 0.31 0.21 0.04 0.23 0.43 360 5.94 2.63 2.85 0.42 27.18 8.24 14.95 361 5.64 0.30 2.85 0.22 2.75 0.43 27.12 O.06 8.48 O.24 15.39 0.44 362 5.35 0.29 3.07 O.22 2.64 0.44 27.05 O.O7 8.72 0.24 15.84 0.45 363 5.06 0.29 8.30 0.23 2.54 0.46 26.97 O.O8 8.96 0.24 16.28 0.44 364 4.79 0.27 3.54 0.24 2.45 0.48 26.86 O. II 9.20 O.24 16.73 0.45 0.26 O.24 0. II O.24 0.45 365 4.53 3.78 2.35 0.50 26.75 9.44 17.18 366 4.27 0.26 4.03 0.25 2.26 0.53 26.62 0.13 9.69 0.25 17.64 0.46 3ii7 4.03 0.24 4.28 0.25 2.16 0.57 26.47 0.15 9.94 0.25 18.11 0.47 368 3.79 0.24 4.53 0.2J 2.07 0.60 26.31 0.16 10.19 0.25 18.58 0.47 369 3.56 0.23 4.79 O.26 1.98 0.65 26.13 o.i 8 10.45 O.26 19.05 0.47 0.21 O.26 0.19 0.25 0.47 370 3.35 5.05 1.89 0.69 25.94 10.70 19.52 371 3.14 O.2I 5.31 0.26 1.81 0.74 25.74 O.2O 10.96 O.26 20.00 0.48 372 2.94 O.20 5.58 0.27 1.72 0.79 25.51 O.23 11.22 0.26 20.48 0.48 373 2.76 0.19 5.85 0.27 1.65 0.84 25.27 O.24 11.48 O.26 20.07 0.49 374 2.58 0.17 6.12 0.27 1.57 0.90 25.02 0.25 11.75 O.27 21.46 0.49 0.17 0.27 0.27 O.26 0.49 375 2.41 6.39 1.50 0.96 24.75 12.01 21.95 376 2.24 0.17 6.66 0.27 1.42 1.02 24.46 0.29 12.28 0.27 22.44 0.49 377 2.09 O.I5 6.94 0.28 1.36 1.08 24.16 0.30 12.65 0.27 22.04 o. 50 378 1.95 0.14 7.22 0.28 1.29 1.15 23.84 0.32 12.82 0.27 23.44 0.50 379 1.81 0.14 7.49 0.27 1.23 1.21 23.51 0.33 13.09 0.27 23.95 0.51 0.13 0.28 0.35 0.27 0.51 380 1.68 7.77 1.17 1.28 23.16 13.36 24.46 381 1.56 0.12 8.04 0.27 1.11 1.35 22.80 0.36 13.63 0.27 24.97 0.51 382 1.45 O. II 8.32 0.28 1.06 1.42 22.42 0.38 13.91 O.28 26.48 0.51 383 1.34 0. II 8.60 0.28 1.01 1.49 22.03 0.39 14.19 O.28 25.09 0.51 384 1.24 O.IO 8.88 0.28 0.96 1.57 21.62 0.41 14.46 0.27 26.51 0.52 0.09 0.27 0.41 O.28 0.52 385 1.15 9.15 0.92 1.64 21.21 14.74 27.03 386 1.06 0.09 9.43 o.i 8 0.87 1.72 20.77 0.44 15.02 0.28 27.50 0.53 387 0.98 0.08 9.70 0.27 0.83 1.79 20.33 0.44 15.30 O.28 28.08 0.52 388 0.91 0.07 9.98 0.28 0.79 1.87 19.88 0.45 15.68 O.28 28.61 0.53 389 0.84 0.07 O.o6 10.25 0.27 0.27 0.76 1.95 19.42 0.46 0.48 15.86 O.28 0.29 29.13 0.52 0.53 390 0.78 10.52 0.72 2.03 18.94 16.15 20.66 391 0.72 O.O6 10.79 0.27 0.70 2.10 18.46 0.48 16.43 0.28 30.19 0.53 392 0.67 0.05 11.06 0.27 0.67 2.18 17.97 0.49 16.71 O.28 30.72 0.53 393 0.62 0.05 11.34 0.28 0.64 2.26 17.47 0.50 17.00 0.29 n 31.25 °-53 394 0.57 0.05 11.60 0.26 0.62 2.35 16.97 0.50 17.28 O.28 31.79 0.54 0.04 0.28 0.52 O.29 °-S3 395 0.53 11.88 0.60 2.43 10.45 17.57 32.32 396 0.50 0.03 12.14 o.*6 0.59 2.51 15.94 0.51 17.86 O.29 32.86 0.54 397 0.46 0.04 12.42 0.28 0.57 2.59 15.42 0.52 18.14 O.28 33.39 °-53 398 0.43 0.03 12.68 0.26 0.56 2.67 14.90 0.52 18.43 O.29 33.93 0.54 399 0.41 0.02 12.95 0.17 0.55 2.75 J4.37 0.53 18.71 O.28 34.46 °-53 0.03 0.27 0.51 O.29 0.54 400 0.38 13.22 0.54 2.83 13.85 19.00 35.00 TABLES OP NEPTUNE. 101 TABLE. VIII. IX. X. XI. XII. XIII. TABLE. VIII. IX. X. XI. XII. XIII. Arg. 4 5 6 7 8 0 Arg. 4 5 6 7 8 9 *, *, *h *, *, 6va *< *>, , •6 * *. to. 0 0.08 0.15 0.94 0.94 0.30 0.80 200 1.12 0.05 0.06 1.26 0.10 0.20 10 0.08 0.14 0.96 1.06 0.28 0.84 210 1.12 0.06 0.04 1.14 0.12 0.16 20 0.10 0.13 0.97 1.19 0.26 0.88 220 1.10 0.07 0.03 1.01 0.14 0.12 30 0.13 0.12 0.96 1.31 0.24 0.91 230 1.07 0.08 0.04 0.89 0.16 0.09 40 0.18 0.10 0.95 1.43 0.22 0.93 240 1.02 0.10 0.05 0.77 0.18 0.07 50 0.23 0.09 0.93 1.54 0.20 0.94 250 •0.97 0.11 0.07 0.66 0.20 0.06 60 0.29 0.08 0.89 1.64 0.18 0.94 260 0.91 0.12 0. 11 0.56 0.22 0.06 70 0.36 0.07 0.85 1.72 0.15 0.93 270 0.84 0.13 0. 15 0.48 0.25 0.07 80 0.44 0.06 0.79 1.79 0.13 0.90 280 0.76 0.14 0.21 0.41 0.27 0.10 90 0.52 0.05 0.73 1.85 0.12 0.87 290 0.68 0.15 0.27 0.35 0.28 0.13 100 0.60 0.04 0.67 1.88 0.10 0.83 300 0.60 0.16 0.33 0.32 0.30 0.17 110 0.68 0.04 0.60 1.90 0.09 0.78 310 0.52 0.16 0.40 0.30 0.31 0.22 120 0.76 0.03 0.52 1.90 0.08 0.72 320 0.44 0.17 0.48 0.30 0.32 0.28 130 0.84 0.03 0.45 1.87 0.07 0.66 330 0.36 0.17 0. 55 0.33 0.33 0.34 140 0.91 0.03 0.38 1.83 0.06 0.59 340 0.29 0.17 0. 62 0.37 0.34 0.41 150 0.97 0.03 0.31 1.77 0.06 0.52 350 0.23 0.17 0.69 0.43 0.34 0.48 160 1.02 0.03 0.25 1.69 0.06 0.45 360 0.18 0.17 0. 75 0.51 0.34 0.55 170 1.07 0.03 0.19 1.60 0.07 0.38 370 0.13 0.17 0.81 0.60 0.33 0.62 180 1.10 0.04 0.14 1.50 0.07 0.32 380 0.10 0.16 0.86 0.70 0.33 0.68 190 1.12 0.05 0.09 1.40 0.09 0.26 390 0.08 0.15 0.91 0.80 0.31 0.74 200 1.12 0.05 0.06 1.26 0.10 0.20 400 0.08 0.15 0.94 0.94 0.30 0.80 TABLE XIV. If the date is earlier than 1779, Jan. 4, or later than 1943, Oct. 15, the values of Psl and Pcl must be corrected as follows, the argument being the year : Year. AP.. APci Year. AP..i APc.i Year. AP..! APC., * II „ 1 61 4.2 — 56.83 — 31.88 1700.0 — 65.57 — 24.94 1943.8 + 72.87 + 16.62 1620.0 — 57.44 — 31.46 1710.0 — 66.53 — 24.02 1950.0 + 73.39 + 15.88 1 630.0 — 58.49 — 30.73 1720.0 — 67.50 — 23.04 1960.0 + 74.21 + 14.68 1640.0 — 59.52 — 29.98 1730.0 — 68.46 — 22.04 1970.0 + 75.02 + 13.44 1650.0 — 60.56 — 29.18 1740.0 — 69.40 — 21.00 1980.0 + 75.81 + 12.18 1660.0 — 61.58 — 28.36 1750.0 — 70.32 — 19.92 1990.0 + 76.58 + 10.88 1670.0 — 62.60 — 27.54 1760.0 71.22 — 18.82 2000.0 + 77.32 + 9.52 1680.0 — 63.62 — 26.70 1770.0 — 72.10 — 17.68 1690.0 — 64.60 — 25.84 1779.0 — 72.87 — 16.62 . Between 1779 and 1943, Ps and Pc require no correction. For dates earlier than 1614 or later than 2000, the corrections must be computed from the formulas. • 102 TABLES OF NEPTUNE. TABLE XV. EQUATION OF THE CENTRE. i Equation. Diff. I Equation. Diff. I Equation. Diff. 0 0 / II n o O 1 II n 0 O 1 II // 180 1 38 54.42 225 057 42.12 270 0 17 6.17 181 1 38 10.17 44-25 22G 05641.74 60.38 271 0 1624.17 42.00 182 1 37 25.21 44.96 1-11 055 41.40 60.34 272 015 42.'.i2 41.25 183 1 3G 39.56 45-65 228 05441.12 60.28 273 0 15 2.45 40.47 184 1 35 53.23 46.33 46.99 229 0 53 40.90 60.22 60.12 274 0 14 22.76 39 69 38.90 185 1 35 6.24 230 0 52 40.78 275 0 13 43.86 186 1 34 18.60 47.64 231 0 51 40.76 60.02 270 013 5.77 38.09 187 1 33 30.33 48.27 232 0 50 40.87 59.89 277 0 1228.50 37-^7 188 1 32 41.43 48.90 233 04941.12 59-75 278 0 11 52.00 36-44 189 1 31 51.93 49.50 234 0 48 41.53 59-59 279 0 11 1G.40 35.60 50.09 59-4" 34-75 190 1 31 1.84 235 0 47 42.12 280 0 1041.71 191 1 30 11.17 50.67 236 0 46 42.90 59.22 281 010 7.82 33-89 192 1 29 19.93 51.14 237 0 45 43.90 59.00 282 0 9 34.81 33.01 193 1 28 28.15 51.78 238 044 45.13 5^-77 283 0 9 2.0'.) 32.12 194 1 27 35.84 52.31 239 0 43 4G.61 58.52 284 0 831.4G 3'-i3 52.81 58-*5 30-33 195 1 26 43.02 240 0 42 48.36 285 0 8 1.13 196 1 25 49.70 53.32 241 0 41 50.39 57-97 286 0 7 31.72 29.41 197 1 24 55.90 53.80 242 0 40 52.72 57.67 287 0 7 3.23 28.49 198 1 24 1.64 54.26 243 0 39 55.36 57.36 288 0 G 35.07 27.56 199 1 23 6.93 54- 7 > 244 0 38 58.34 57.02 289 0 G 9.0G 26.61 SS-'S 56.67 25.67 200 1 22 11.78 245 038 1.67 290 0 5 43.39 201 1 21 16.21 55-57 246 037 5.37 56.30 291 0 5 18.08 24.71 202 1 20 20.25 55.96 247 0 36 9.45 55-92 392 0 4 54.94 23-74 203 204 1 19 23.90 1 1827.19 56-35 56.71 57.06 248 249 035 13.94 0 34 18.84 55-5» 55.10 54.66 293 294 0 432.18 0 4 10.40 22.76 21.78 20.80 205 1 17 30.13 250 0 33 24.18 295 0 3 49.00 206 1 16 32.73 57-40 251 0 32 29.97 54.21 296 0 3 29.80 19.80 207 1 15 35.02 57-71 252 0 31 36.22 53-75 297 0311 .00 18.80 208 1 14 37.01 58.01 253 0 30 42.96 53.26 298 0 2 .ri3.21 17.79 209 1 13 38.72 58.29 254 0 29 50.19 52.77 299 0 2 :;o.-ll 16.77 58.56 52-25 15.76 210 1 12 40.16 265 0 28 57.94 300 0 2 20.08 211 1 11 41.35 58 81 256 028 6.22 51.71 301 0 2 5.05 >4-73 212 1 10 42.32 59-oj 257 0 27 15.05 51.17 302 0 1 52.26 13.69 213 1 943.08 59- *4 258 0 26 24.43 50.62 308 0 1 39.00 12.66 214 1 8 43.64 59-44 259 0 25 34.40 50.03 304 0 1 27.97 1 1.63 59.61 49-45 10.58 215 1 744.03 260 0 24 44.95 -805 0 1 17.39 216 1 644.26 59-77 261 02356.11 48.84 306 0 1 7.85 9-54 217 1 5 44.35 599' 2G2 023 7.89 48.22 307 0 0 59.30 8.49 218 1 444.32 60.03 2G3 0 22 20.31 47-58 308 0 051.93 7-43 219 1 3 44.18 60.14 264 0 21 33.37 46.94 309 0 045.55 6.38 60.23 46.27 53' 220 1 243.95 265 0 20 47.10 310 0 040.24 221 1 1 43.65 60.30 289 020 1.50 45.60 311 0 0 30.00 4 24 222 1 043.30 60.35 207 0 19 16.60 44-90 312 0 032.82 3.18 223 0 59 42.92 60.38 268 0 18 32.40 44.20 313 0 0 30.71 2.1 I 224 0 58 42.62 60.40 269 0 17 48.92 43.48 314 0 0 29.07 I.O4 60.40 4^-75 0.03 225 0 57 42.12 270 017 6.17 315 0 0 29.70 TABLES OP NEPTUNE. 103 TABLE XV. EQUATION OF THE CENTRE (Continued). i Equation. Diff. I Equation. Diff. I Equation. Diff. o 0 1 II // O O 1 II If O O 1 II H 315 0 029.70 0 018 11.18 45 1 024.20 316 317 0 0 30.80 0 0 32.00 I.IO 2.16 1 2 0 18 55.91 0 19 41.40 44-73 45-49 46 47 1 1 26.40 1 2 28.66 62.2O 62.16 318 0 03G.20 3.24 3 0 20 27.63 46.23 48 1 3 30.65 62.09 319 0 040.50 4.30 4 0 21 14.59 46.96 49 1 4 32.67 62.02 5.38 47.67 61.91 320 0 045.88 5 0 22 2.26 50 1 5 34.58 321 0 052.33 6.45 6 022 50.63 48-37 51 1 6 36.37 61.79 322 0 0 59.84 7-5' 7 0 23 39.68 49.05 52 1 7 38.02 61.65 323 0 1 8.42 8.58 8 0 24 29.40 49-72 53 1 8 39.51 61.49 324 0 1 18.06 9.64 9 0 25 19.78 50.38 54 1 940.82 61.31 10.70 51.01 61.11 325 0 1 28.76 10 0 26 10.79 55 1 10 41.93 326 327 328 0 1 40.52 0 1 53.34 0 2 7.21 11.76 12.82 13.87 11 12 13 0 27 2.43 0 27 54.67 0 28 47.50 51.64 52.24 52.83 56 57 58 1 11 42.82 1 12 43.46 1 13 43.85 60.89 60.64 60.39 329 0 2 22.13 14.92 14 0 29 40.91 53-41 59 1 14 43.96 60. ii '5-97 53.96 59.82 330 0 2 38.10 15 0 30 34.87 60 1 15 43.78 331 0 2 55.11 17.01 16 0 31 29.38 54-5' 61 1 16 43.28 59.50 332 0 3 13.1ii 18.05 17 0 32 24.41 55-°3 62 1 17 42.45 59-'7 333 0 3 32.24 19.08 18 0 33 19.95 55-54 63 1 18 41.27 58.82 334 0 3 52.35 20.11 21.13 19 0 34 15.97 56.02 56.50 64 1 19 39.71 58.44 58.05 335 0 4 13.48 20 0 35 12.47 65 1 20 37.76 886 0 4 35. (52 22.14 21 036 9.42 56.95 66 1 21 35.41 57-65 337 338 0 458.78 0 5 22.94 23.16 24.16 22 23 0 37 6.81 038 4.61 57-39 57.80 67 68 1 22 32.62 1 23 29.39 57.21 56.77 339 0 5 48.09 *5-i5 24 0 39 2.81 58.20 69 1 24 25.70 56.31 26.15 58.59 55-83 340 0 6 14.24 25 040 1.40 70 1 25 21.53 341 0 G41.37 27.13 26 041 0.35 58-95 71 1 26 16.87 55-34 342 0 7 9.47 28.10 27 0 41 59.64 59.29 72 1 27 11.69 54.82 343 0 7 38.54 29.07 28 0 42 59.26 59.62 73 1 28 5.97 5428 344 0 8 8.57 30.03 29 04359.19 59-93 74 1 28 59.71 53-74 30.97 60.22 53-'7 345 0 839.54 30 0 44 59.41 75 1 29 52.88 346 0 911.46 31.92 31 0 45 59.90 60.49 76 1 30 45.46 52.58 347 0 9 44.30 32.84 32 0 47 0.63 60.73 77 1 31 37.45 51.99 348 0 10 18.07 33-77 33 048 1.60 60.97 78 1 32 28.82 5'-37 349 0 10 52.74 34-67 34 049 2.78 ftl.lS 79 1 33 19.55 5°-73 3S-58 61.38 50.09 350 0 11 28.32 35 050 4.16 80 1 34 9.64 351 012 4.79 36.47 36 051 5.71 61.55 81 1 34 59.06 49.42 352 353 0 1242.14 0 13 20.35 37-35 38.21 37 38 052 7.41 0 53 9.25 61.70 61.84 82 83 1 35 47.80 1 36 35.85 48.74 48.05 354 0 13 59.42 39-°7 39 05411.20 61.95 84 1 37 23.19 47-34 39.92 62.05 46.61 355 0 14 39.34 40 0 55 13.25 85 1 38 9.80 356 0 1520.09 40.75 41 0 56 15.37 6.2. 12 86 1 38 55.67 45-87 357 0 16 1.66 4'-57 42 0 57 17.54 62.17 87 1 39 40.80 45-'3 358 0 16 44.04 42.38 43 0 58 19.75 62.21 88 1 4025.15 44-35 359 0 17 27.22 43.18 44 05921.98 62.23 89 1 41 8.73 43-58 43.96 62.22 42.78 300 01811.18 45 1 024.20 90 1 41 51.51 104 TABLES OF NEPTUNE. TABLE XV. EQUATION OF THE CENTRE (Concluded). i Equation. Diflf. I Equation. Diff. I Equation. Diff. 0 Of ft // o O / /' ft o O ' H // 90 I 41 51.51 120 1 66 10.41 150 1 54 54.44 91 1 42 33.48 41-97 121 1 56 23.47 13.06 151 1 54 35.48 18.96 92 1 43 14.63 41.15 122 1 56 35.47 12. OO 152 1 54 15.50 19.98 93 1 43 54.95 40.31 123 1 56 46.39 10.92 153 1 53 54.51 20.99 94 1 44 34.42 39-47 38.61 124 1 60 5G.24 9.85 8.78 154 1 63 32.52 21.99 22.99 95 1 45 13.04 125 1 67 5.02 155 1 53 9.53 96 97 1 45 50.78 1 4 56 3804 '43 " 116 9631 628 176 6942 474 57 3958 '54 117 770262 631 177 6408 466 58 4123 165 118 0895 633 178 6866 458 59 4300 '77 119 1531 636 179 7317 45' CO 744487 187 120 772170 639 180 807759 442 110 TABLES OF NEPTUNE. TABLE XXII. COEFFICIENTS FOR PERTURBATIONS OF LATITUDE. Argument 1. Arg. 0 100 200 800 -B..1 -Bc.1 A, Ba B..I B* B*l Ba // // It n n n n n 0 0.52 0.40 0.41 0.00 0.04 0.18 0.14 0.58 10 0.56 0.35 0.31 0.00 0.04 0.18 0.21 0.05 20 0.61 0.31 0.23 0.03 0.04 0.17 0.30 0.70 30 0.67 0.27 0.15 0.06 0.03 0.18 0.38 0.73 40 0.72 0.23 0.09 0.10 0.02 0.20 0.45 0.73 50 0.73 0.18 0.05 0.13 0.01 0.23 0.50 0.70 60 70 0.72 0.67 0.13 0.08 0.03 0.02 0.16 0.17 0.01 0.02 0.28 0.34 0.52 0.52 0.65 0.59 80 0.59 0.04 0.03 0.18 0.04 0.42 0.51 0.62 90 0.50 0.01 0.04 0.18 0.08 0.50 0.51 0.40 100 0.41 0.00 0.04 0.18 0.14 0.58 0.52 0.40 PERTURBATIONS OF LATITUDE. TABLE XXIII. TABLE XXIV. Arg. Arg. 5. Arg. 8. 0 100 200 300 0 100 200 300 It // ff H „ „ II „ 0 — 0.30 + 0.06 + 0.30 — 0.06 + 0.04 + 0.56 — 0.04 — 0.56 10 20 30 40 — 0.29 — 0.27 — 0.24 — 0.21 + 0.11 + 0.16 + 0.19 + 0.23 + 0.29 + 0.27 + 0.24 + 0.21 — 0.11 — 0.16 — 0.19 — 0.23 + 0.13 + 0.21 + 0.29 + 0.36 + 0.55 + 0.52 + 0.48 + 0.43 — 0.13 — 0.21 — 0.29 — 0.36 — 0.55 — 0.52 — 0.48 — 0.43 50 — 0.17 + 0.26 + 0.17 — 0.26 + 0.43 + 0.37 — 0.43 — 0.37 GO 70 80 90 — 0.12 — 0.08 — 0.03 + 0.02 + 0.28 + 0.30 + 0.31 + 0.81 + 0.12 + 0.08 + 0.03 — 0.02 — 0.28 — 0.30 — 0.31 — 0.31 + 0.48 + 0.52 + 0.55 + 0.56 + 0.30 + 0.22 + 0.14 + 0.05 — 0.48 — 0.52 — 0.55 — 0.50 — 6.30 —0.23 — 0.14 —0.08 100 + 0.06 + 0.30 — 0.06 — 0.30 + 0.56 — 0.04 — 0.56 + 0.04 TABLE XXV. VALUES OF SIN i FOR EVERT TEN YEARS. Year. 1600 1700 1800 1900 0 8.498705 8.496503 8.494292 8.402066 10 20 30 40 8485 8265 8045 7825 220 6282 6061 5840 6619 221 221 221 221 221 4071 3849 3627 8404 III 1X12 "4 ir.i-.i "3 1896 im »4 50 8.497605 8.495398 8.493182 8.490947 60 70 80 'JO 7385 *10 7165 6944 C724 - 5177 4956 4735 4513 221 221 221 22£ 221 2'.i;V.) "3 2736 2513 2289 "4 "i 0723 "4 0-108 0274 8.490(149 "•• 100 8.496503 8.494292 8.492006 8.489824 PUBLISHED BY THE SMITHSONIAN INSTITUTION, WASHINGTON, D. C. 3 A N D ARY, 1866. •.. ail •'-. -?;•;%'-»*::;•*-• yMms^m^ U.C. BERKELEY LIBRARIES , : 9R8S J^.H UNIVERSITY OF CALIFORNIA LIBRARY