Trinidad Achernar 10 38 56.1 10 38 58.2 2.1 Alph.Gruris 52.2 50.8 1.4 Achernar 59.3 56.6 2.7
Jamaica Polaris 17 56 8.6 17 56 4.6 4.0 6.6 3.3 3.3
New York Sun 40 42 40.1 40 42 44.6 4.5 Polaris 48.9 38.2 10.7 Sun 41.4 47.2 5.8 Beta Urs.Min. 42.3 58.4 16.1
Hammerfest Sun 70 40 5.3 70 40 7.2 1.9
Spitzbergen Sun 79 49 56.1 79 49 58.6 2.5 Sun 55.9 44.8 11.1 Sun 58.6 52.7 5.9 Sun 59.3 51.6 7.7 Sun 55.8 51.6 4.2 Sun 50 1.5 57.0 4.5
Greenland Sun 74 32 19.9 74 32 32.4 12.4 Sun 17.9 18.7 0.8
Drontheim Sun 63 25 51.3 63 26 6.1 14.8 Alph.Urs.Min. 57.2 49.4 7.8
This presents a very different view of the lat.i.tudes as determined by the small repeating circle, from that in Captain Sabine"s book; and confining ourselves still to Maranham, where the lat.i.tudes "WERE OBTAINED, WITH ESPECIAL REGARD TO EVERY CIRc.u.mSTANCE BY WHICH THEIR ACCURACY MIGHT BE AFFECTED," and where "A MORE THAN USUAL ATTENTION WAS BESTOWED," it appears, that if we take Captain Sabine"s own test, namely, "the differences of the partial results from the mean at each station," the deviations become nearly ten times as large as they were before; a circ.u.mstance which might be expected to have some influence in the decision of the question.
There is, however, another light in which it is impossible to avoid looking at this singular oversight. The second column of the table of lat.i.tudes must now be considered the true one, as that which really resulted from the observations. Now, on examining the column of true lat.i.tudes, the differences between the different sets of observations is so considerable as naturally to excite some fear of latent error, more especially as nearly the greatest discordance arises from the same star, Alph.Lyrae, observed after an interval of only three days. It becomes interesting to every person engaged in making astronomical observations, to know what is the probability of his being exposed to an error so little to be guarded against, and so calculated to lull the suspicions of the unfortunate astronomer to whom it may happen.
In fact, the question resolves itself into this: the true lat.i.tude of a place being determined by sets of observations as in the first of the following columns--
Lat.i.tudes as True lat.i.tudes observed. computed by a mistake of Capt. Sabine"s.
deg.min.sec. deg.min.sec.
Alph.Lyrae, 28th Aug.... 2 31 22.0 2 31 42.4 Alph.Lyrae, 29th Aug.... 31.8 43.8 Alph.Pavonis, 29th Aug... 44,0 44.5 Alph.Lyrae, 31st Aug.... 42.6 44.6 Alph.Cygni, 31st Aug.... 39.2 42.0 Alph.Gruris, 2d Sept.... 27.4 42.2
what are the chances that, by one error all the lat.i.tudes in the first column should be brought so nearly to an agreement as they are in the second column? The circ.u.mstance of the number of divisions of the level being almost arbitrary within limits, might perhaps be alleged as diminishing this extraordinary improbability: but let any one consider, if he choose the error of each set, as independent of the others, still he will find the odds against it enormous.
When it is considered that an error, almost arbitrary in its law, has thus had the effect of bringing discordant observations into an almost unprecedented accordance, as at Maranham; and not merely so, but that at eight of the nine stations it has uniformly tended to diminish the differences between the partial results, and that at the ninth station it only increased it by a small fraction of a second, I cannot help feeling that it is more probable even that Captain Kater, with all his admitted skill, and that Captain Sabine himself, should have been both mistaken in their measures of the divisions of the level, than that so singular an effect should have been produced by one error; and I cannot bring myself to believe that such an antic.i.p.ation is entirely without foundation.
Whatever may be the result of a re-examination, it was a singular oversight NOT TO MEASURE the divisions of a level intended to be used for determining so important a question; more particularly as, in the very work to which reference was made by Captain Sabine for the purpose of comparing the observations, it was the very first circ.u.mstance which occupied the French philosophers, and several pages [See pages 265 to 275 of the RECUEIL D"OBSERVATIONS GEODESIQUES, &c. PAR MM. BIOT ET ARAGO, which forms the fourth volume of the BASE DU SYSTEME METRIQUE.]
are filled with the details relative to the determination of the value of the divisions of the level. It would also have been satisfactory, with such an important object in view, to have read off some of the sets after each pair of observations, in order to see how far the system of repet.i.tion made the results gradually converge to a limit, and in order to know how many repet.i.tions were sufficient. Such a course would almost certainly have led to a knowledge of the true value of the divisions of the level; for the differences in the alt.i.tude of the same star, after a few minutes of time, must, in many instances, have been far too great to have arisen from the change of its alt.i.tude: and had these been noticed, they must have been referred to some error in the instrument, which could scarcely, in such circ.u.mstances, have escaped detection.
I have now mentioned a few of the difficulties which attend Captain Sabine"s book on the pendulum, difficulties which I am far from saying are inexplicable. He would be bold indeed who, after so wonderful an instance of the effect of chance as I have been just discussing, should venture to p.r.o.nounce another such accident impossible; but I think enough has been said to show, that the feeling which so generally prevails relative to it, is neither captious nor unreasonable.
Enough also has appeared to prove, that the conduct of the Admiralty in appointing that gentleman one of their scientific advisers, was, under the peculiar circ.u.mstances, at least, unadvised. They have thus lent, as far as they could, the weight of their authority to support observations which are now found to be erroneous. They have thus held up for imitation observations which may induce hundreds of meritorious officers to throw aside their instruments, in the despair of ever approaching a standard which is since admitted to be imaginary; and they have ratified the doctrine, for I am not aware their official adviser has ever even modified it, that diminutive instruments are equal almost to the largest.
To what extent this doctrine is correct, may perhaps yet admit of doubt.
It cannot, however, admit of a doubt, that it is unwise to crown it with official authority, and thus expose the officers of their service to depend on means which may be quite insufficient for their purpose.
How the Board of Longitude, after EXPRESSLY DIRECTING THIS INSTRUMENT TO BE MADE AND TRIED, could come to the decision at which they arrived, appears inexplicable. The known difference of opinion amongst the best observers respecting the repeating principle, ought to have rendered them peculiarly cautious, nor ought the opinion of a Troughton, that instruments of less than one foot in diameter may be considered, "FOR ASTRONOMY, AS LITTLE BETTER THAN PLAYTHINGS," [Memoirs of the Astronomical Society, Vol.I. p.53.] to have been rejected without the most carefully detailed experiments. There were amongst that body, persons who must have examined minutely the work on the Pendulum.
Captain Kater must have felt those difficulties in the perusal of it which other observers have experienced; and he who was placed in the Board of Longitude especially for his knowledge of instruments, might, in a few hours, have arrived at more decisive facts. But perhaps I am unjust. Captain Kater"s knowledge rendered it impossible for him to have been ignorant of the difficulties, and his candour would have prevented him from concealing them: he must, therefore, after examining the subject, have been outvoted by his lay-brethren who had dispensed with that preliminary.
It would be unjust, before quitting this subject, not to mention with respect the acknowledgment made by an officer of the naval service of the errors into which he also fell from this same level. Lieutenant Foster, aware of the many occasions on which Captain Sabine had employed this instrument, and knowing that he considered each division as equal to one second, never thought that a doubt could exist on the subject, and made all his calculations accordingly. When Captain Kater made him acquainted with the mistake, Lieutenant Foster immediately communicated a paper [The paper of Lieutenant Foster is printed in the Philosophical Transactions, 1827, p.122, and is worth consulting.] to the Royal Society, in which he states the circ.u.mstance most fully, and recomputed all the observations in which that instrument was used. Unfortunately, from the original observations of Mr. Ross being left on board the Fury at the time of her loss, the transcripts of his results could not be recomputed like the rest, and were consequently useless.
SECTION 5. OF THE UNION OF SEVERAL OFFICES IN ONE PERSON.
Although the number of situations to which persons conversant with science may hope to be appointed, is small, yet it has somewhat singularly happened, that instances of one individual, holding more than one such appointment, are frequent. Not to speak of those held by the late Dr. Young, we have at present:--
MR. POND--Astronomer Royal, Inspector of Chronometers, and Superintendent of the Nautical Almanac.
CAPTAIN SABINE--An officer of artillery on leave of absence from his regiment; Secretary of the Royal Society; and Scientific Adviser of the Admiralty.
MR. BRANDE--Clerk of the Irons at the Royal Mint; Professor of Chemistry at the Royal Inst.i.tution; a.n.a.lyser of Rough Nitre, &c. to the East-India Company; Lecturer on Materia Medica, Apothecaries" Hall; Superintending Chemical Operator at ditto; Lecturer on Chemistry at ditto; Editor of the Royal Inst.i.tution Journal; and Foreign Secretary to the Royal Society.
One should be led to imagine, from these unions of scientific offices, either that science is too little paid, and that gentlemen cannot be found to execute the offices separately at the salaries offered; or else, that it is too well paid, since each requires such little attention, that almost any number can be executed by one person.
The Director of the Royal Observatory has a larger and better collection of instruments, and more a.s.sistants to superintend, than any other astronomer in the world; and, to do it properly, would require the almost undivided attention of a man in the vigour of youth. Nor would a superintendent of the Nautical Almanac, if he made a point of being acquainted with every thing connected with his subject, find his situation at all a sinecure. Slight as are the duties of the Foreign Secretary of the Royal Society, it might have been supposed that Mr.
Brande would scarcely, amongst his multifarious avocations, have found time even for them. But it may be a consolation to him to know, that from the progress the Society is making, those duties must become shortly, if they are not already, almost extinct.
Doubtless the President, in making that appointment, looked most anxiously over the list of the Royal Society. He doubtless knew that the Academics of Sweden, of Denmark, of Scotland, of Prussia, of Hanover, and of France, derived honour from the discoveries of their Secretaries;--that they prided themselves in the names of Berzelius, of Oersted, of Brewster, of Encke, of Gauss, and of Cuvier. Doubtless the President must have been ambitious that England should contribute to this galaxy of glory, that the Royal Society should restore the lost Pleiad [Pleiades, an a.s.semblage of seven stars in the neck of the constellation Taurus. There are now only six of them visible to the naked eye.--HUTTON"S DICTIONARY--Art. Pleiades.] to the admiring science of Europe. But he could discover no kindred name amongst the ranks of his supporters, and forgot, for a moment, the interest of the Society, in an amiable consideration for the feelings of his surrounding friends.
For had the President chosen a brighter star, the l.u.s.tre of his other officers might have been overpowered by its splendour: but relieved from the pain of such a contrast, he may still retain the hope, that, by their united brightness, these suns of his little system shall yet afford sufficient light to be together visible to distant nations, as a faint NEBULA in the obscure horizon of English science.
SECTION 6. OF THE FUNDS OF THE SOCIETY.
Although the Society is not in a state approaching to poverty, it may be useful to offer a few remarks respecting the distribution of its money.
EXPENSE OF ENGRAVINGS FOR SIR E. HOME"S PAPERS.--The great expense of the engravings which adorn the volumes of the Philosophical Transactions, is not sufficiently known. That many of those engravings are quite essential for the papers they ill.u.s.trate, and that those papers are fit for the Transactions, I do not doubt; but, some inquiry is necessary, when such large sums are expended. I shall endeavour, therefore, to approximate to the sum these engravings have cost the Royal Society.
Previous to 1810, there are upwards of seventy plates to papers of Sir E. Home"s; in many of these, which I have purposely separated, the workmanship is not so minute as in the succeeding ones. Since 1810, there have occurred 187 plates attached to papers of the same author.
Many of these have cost from twelve to twenty guineas each plate; but I shall take five pounds as the average cost of the first portion, and twelve as that of the latter. This would produce,
70 X 5 = 350 187 X 12 = 2244 ...... -----...... L2594
As this is only proposed as a rough approximation, let us omit the odd hundreds, and we have two thousand pounds expended in plates only on ONE branch of science, and for one person! Without calling in question the importance of the discoveries contained in those papers, it may be permitted to doubt whether such a large sum might not have been expended in a manner more beneficial to science. Not being myself conversant with those subjects, I can only form an opinion of the value from extraneous circ.u.mstances. Had their importance been at all equal to their number, I should have expected to have heard amongst the learned of other countries much more frequent mention of them than I have done, and even the Council of the Royal Society would scarcely have excluded from their Transactions one of those productions which they had paid for as a lecture.
It might also have been more delicate not to have placed on the Council so repeatedly a gentleman, for whose engravings they were annually expending, during the last twenty years, about an hundred pounds. On the other hand, when the Council lent Sir E. Home the whole of those valuable plates to take off impressions for his large work on Comparative Anatomy, of which they const.i.tute almost the whole, it might have been as well not to have obliterated from each plate all indication of the source to which he was indebted for them.
THE PRESIDENT"S DISCOURSES.--I shall mention this circ.u.mstance, because it fell under my own observation.
Observing in the annual accounts a charge of 381L 5s. for the President"s Speeches, I thought it right to inquire into the nature of this item. Happening to be on the Council the next year, I took an opportunity, at an early meeting of that Council, to ask publicly for an explanation of the following resolution, which stands in the Council-books for Dec. 21, 1828.
"Resolved, That 500 copies of the President"s Discourses, about to be printed by Mr. Murray, be purchased by the Society, at the usual trade price."
The answer given to that question was, "THAT THE COUNCIL HAD AGREED TO PURCHASE THESE VOLUMES AT THAT PRICE, IN ORDER TO INDUCE MR. MURRAY TO PRINT THE PRESIDENT"S SPEECHES."
I remarked at the time that such an answer was quite unsatisfactory, as the following statement will prove.
The volume consists of 160 pages, or twenty sheets, and the following prices are very liberal:
L s. d.
To composing and printing twenty sheets, at 3L. per sheet............... 60 0 0 Twenty reams of paper, at 3L. per ream..... 60 0 0 Corrections, alterations, &c.......... 30 0 0