Views of astronomy : seven lectures delivered before the Mercantile Library Association of New York in the months of January and February, 1848 / by J.P. Nichol ; reported for the New-York Tribune by Oliver Dyer.
- John Pringle Nichol
- Date:
- 1848
Licence: Public Domain Mark
Credit: Views of astronomy : seven lectures delivered before the Mercantile Library Association of New York in the months of January and February, 1848 / by J.P. Nichol ; reported for the New-York Tribune by Oliver Dyer. Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![result eamo oat sufficiently concordant with that set, bot wholly discordant with the other set; so that Bouvard was obliged to conclude that these two classes offsets were incompatible: and the next point was, what could be the reason of that incompatibility 7 Perhaps no conclusion was so probable at the time as that to which Bouvard, amid much misgiving, saw it expedient to come; viz. that the old observations might have been less accurate than the modern ones, throuuh the imperfection of the old instruments ; and that, therefore, they should in this inquiry be set aside, The conclusion was indeed a bold one, I had almost said audacious.• for among the ob- servers on whose authority these old places of Uranus reposed, we find Mayer and the industrious Flamstead, and, far above all, our incomparable Bradley : nor was the ingenious Frenchman blind to the difficulties encompassing the course he found himself constrained to choose. Such, says he, is the alternative presented by the formation of the tables of the planet Uranus, that if the ancient observations are compared with the modern ones, the first are passably represented, while the second are not so with the precision they demand ; and if either set be rejected, tables are the result which satisfy the ones retained, but do not satisfy the others. It being then necessary, adds Bouvard, to decide between tbem, I have held by the mod- ern observations, as being the most likely to be ac- curate, and I leave Time to come in aid of the diffi- culty of reconciling these older ones, and of ex- plaining whether it is caused by the inexactness of these old observations, or depends on some foreign and yet unperceived influence to which the planet is subjected. And a very satisfactory light in r - gard of the difficulty was quickly afforded by time. If Bouvard had been right, then the movements of Uranus subsequent to 1820, would necessarily have ogreed with the orbit deduced from the observations between 1781 and 1820: but, on the very contrary, the planet has since been moving apparently without the remotest regard to that orbit, and in defiance of all known rule. Not only, then, was it necessary to reject the old observations in order to sustain the authority of Bouvard's deter- mination, but those more recent ones in regard of whose authenticity and scrupulous correctness,not a shadow of doubt could be intimated, had also to be summarily thrown aside. As with Kepler, in his pursuit of the true orbit of Mars, no sooner was the Planet, in one part of its course, brought under control and properly enchained, than.lo ! at another part he broke from all bondage, and rushed wither he would! The actual state of this very puzzling case is represented in the following diagrams: ■781Si SbpISsibeSSSSS' iSSni'lacBSSSSSS !52!S2=Sn3: 179d ■■ ■■ 1798 ■BBBBHL-IBaPflBHBBBBBBBBk'aBBaBBBqBDaSBBBailBBBBBBBaBBaBBaa ^01 BBBBBBBlSBBBBBBBBBBBBBaBliaSBBBBBBBBBBBBBBBBBBBaBBBBBBBB ISO! ■ BBaBBBXBBBBBBBaBBBBBBBBBBBS<!HaBaBBBBBBBBaBBBBBBBai IBB ■BBBBaBB^aBBEaBaBBBaBanaBBBaBHBBa£a«aBBBBBBBBaaaBB8BaB ..-,„ ■BBBBBBSlBBBBBBaBnBEBaBEaBaaaBSBBBBBH*8BBaaBBBBaBBBBaaE i810 ' aBaBUarjaBBaBiaBC<BBBaB8aBaBaBBBBISBBBBBB*BBBBBaBBBBBBBBBB ■BBBBBtzaaBBNaaaaaaBBaBBBaaaBBaaaBBBBaaiaaaasBBBaBBMaaB ■BaaBaai'aBBBBBSdBaaBBaBBBBBaaBBBBBBBaBttBBBasaaaEaBBBBfl ■BB*ssaaaBBBBaaaBBBBBBBBsaBBBaaaBsaBapaaaaaaaaBBBaBBaB 1S20 ■BS=BBBBBBBBBBiS]EBBBBBBBBBBBBBBBBBBBB5BBaBBBaBBBBEBBBBai82<> ■ BBBBl£<«aBaBB«aaBaBaBBBBBBa*B*===SaaaBBBBBBBaBBBBBBBBaa 1830 BIBBBBBBfiSBBH ■flBBflBBBBBBBBVBBBBIiaBBBHBKBBBBBBBaflBBBBBBB 1330 ;R40 ■■ BBBMHBBBBBBBBBBB ■BBBBBBBBaBSSBBBBBBB liZBBB lfi5 ■BBBBBUBaaaBBBBBBBBBBBBBBBBBBBBBaKaBBBBBBBBBBaBBaBBBBB IbBBBBBBBBBBBEBBBBB BBBaaBBBBBBBBflNBBBSBEl ■■■■■■BBBBaBBBBBaaBBBBBaBBBBBBBBBBBBBBBMBBBBBaaBBBBBBa ■BBBBBBaaBBaBBBBBBBBaBBBBaBBBaaBRflBaaBBBflaBaBBBaBBBaaa ■aBBaBl^JBBBBBBBBBBBBaBBBBBaBBBBBLJBBaBBBBBaBaBBBIBaBH P If the line A B, in fig. 1, represent the observed orbit of Uranus, the broken line will exhibit the theoretical orbit,—that calculated from the epoch 1781 to 1840 being traced by the irregular line. Now, the deviation of the two lines—one-tenth of > presents the observed orbit as determined by those separate acts of observation between lGDOand 177L The dotted irregular line, on a scale only one-half of the previous one (a second being represented by half a tenth of an inch,) i* now the representation of the theoretical orbit of Bouvard ! No marvel, in- deed, that Uranus had come to be accounted the puzzle of our science,—no wonder that so many minds were turned to this portion of the celestinl mechanism, in confident expectation that the anom- alies would in time be resolved, by the occurrence of some capital discovery. How difficult it is to follow, in our inquiries, the an inch corresponding to one second of space—ie the measure of this discrepancy between Theory and Fact; a discrepancy which in degree had no parallel elsewhere in Astronomy. Turn, however, to the diagram below, where the line A B again re- 1G90, Flam«tead. 1712-15, Flamstead. 17f>0, Lemonnier. (.763 56, Mayer & Bradli-y. 1701, Lemonnier. 1768-6'J, Lewonnier. easy rules laid down by the immortal Vercxam ! Even when the temptations to go aside are slight, men will not confine themselves to the only road that can ever lead to a revelation of the secret pro- cesses of Nature: on the occurrence of any diffi- culty, they set a-guessing instead ; not after thai, only legitimate fashion—the way in which Geniur apprehends, combines, and follows the applicable analogies that lie around it—but literally almost at random, and with no apparent aim save the desire to avoid confessing that there exists something, of which, in the meantime, they know neither tho method nor the cause. It were positively tedious,](https://iiif.wellcomecollection.org/image/b21143821_0021.jp2/full/800%2C/0/default.jpg)
