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HISTORY OF PHYSICAL ASTRONOMY.

of liis reasoning, tliat the only rational mode of "writing tlie history of thesciences is to rely exclusively on publications, the dates of which are wellascertained, and he hence infers that Mr. Adams has no right to bementioned in connexion with the discovery of the Trans-Uranian planet,either by a detailed citation, or by any allusion whatever. It will at onceoccur to the reader that the force of this proposition depends entirely onthe pi-ecise meaning applied to the term publication. If it be restrictedto printed documents, we conceive that the principle advanced by M.Arago is totally untenable, and that it essentially vitiates any conclusionthat may be derived from it. To limit the test of decision in disputedquestions of scientific discovery to such a species of evidence would be atonce repugnant to reason and at variance with the common practice ofmankind in all ages. Are communications transmitted to learned societies,or documents of an authentic character, addressed to persons of acknow-ledged probity and occupying official positions, to be set at nought as somuch waste paper, merely because they have not passed through theordeal of the printing press ? To admit such a monstrous propositionwould be striking at the root of those unalterable principles of commonsense upon which our primary notions of evidence are founded, and tointroduce in their stead an arbitrary standard of decision which, so far fromdefining clearly the rights of rival claims, would itself perpetually form thesubject of acrimonious controversy. We have no reason however to sup-pose that the illustrious philosopher, who drew up the paper in question,was really of opinion that the evidence which could be of any utility inestablishing claims to scientific research rested on so narrow a basis. Onthe contrary, we are disposed to infer from the acknowledged acuteness ofhis discriminating powers, and his enlightened zeal in the cause of truth,that his sentiments as above expressed, demand a more liberal interpre-tation, and that in the present instance, had he been in possession of allthe facts relating to the disputed question, he would have arrived at aconclusion more consistent with reason and justice than that to which hewas conducted by the imperfect statements then accessible to him *.

The question of Mr. Adams’ merits in connexion with the theoreticaldiscovery of the planet exterior to Uranus , was soon placed in a clear light.On the 13th of November, 1846, a paper was read by Mr. Airy before theAstronomical Society, entitled “An Historical Statement of Circumstancesconnected with the Discovery of the Planet beyond Uranus .” Thisvaluable communication, besides containing a large mass of interestingmaterials bearing more or less on the discovery of the planet, exhibits, inone unbroken chain of correspondence, the progress of Mr. Adams’researches, from the date of Professor Challis’ first letter to the AstrouomerRoyal on the subject in February, 1844, down to the acknowledgment atGreenwich of Mr. Adams’ paper, dated the 2nd September, 1846. Theindependent character of Mr. Adams’ researches was now placed beyondall doubt or equivocation, and his claims to the theoretical discovery ofthe planet established on the incontrovertible evidence of authentic docu-ments. Mr. Adams’ Memoir on the Perturbations of Uranus was readbefore the Astronomical Society on the same day on which Mr. Airycommunicated his statement, and was subsequently published in thesixteenth volume of the Memoirs of the Society, and also in the Nautical

* See in connexion with these remarks the note at the foot of page 214, in the nextchapter.