It may appear somewhat presumptuous for the present writer to further dwell on some points of subordinate importance, even with the view of supplementing the investigations of Professor Dall; but he is encouraged to the effort by the admirable spirit in which that gentleman works, which is so clearly indicated in his own words: "I am well aware this paper cannot be regarded as a finality, but as a contribution to the geographical history of North America it will not be without its value." This spirit encourages every one to contribute his mite to elucidate the history of this interesting and ill-known period.
The supplementary remarks now presented mainly relate to two points: first, the cartographic reproduction of Bering's discoveries; second, the alleged observations of lunar eclipses in Kamshatka by Bering and his lieutenants in 1728–'29.
In attempting to add to Professor Dall's essay or to elucidate some points, it is but natural to felicitate one's self that chance has put in one's way rare data in the shape of text and map. Nevertheless, much difficulty has been experienced in efforts to consult publications and charts bearing on this subject, as supplementary to the data in the writer's own library. Fortunately, among his personal books and maps are the following, which have escaped the critical, if not casual, observation of Professor Dall:
1. The original Hague1 edition of Père du Halde, which Dall was unable to consult; it is entitled "Description Géographique, Historique, Chronologique, Politique, et Physique de l'Empire et de la Tartarie Chinoise," etc. 4 vols., 4°: à la Haye, 1736.
1 The first edition, in French, was published at Paris, 4 vols., folio, 1735.
2. De l'Isle's scattered essays, entitled "Mémoires pour servir à l'histoire et au progres de l'Astronomie, de la Géographie, et de la Physique, etc., etc.: à St. Petersbourg, de l'imprimeris de l'Académie des Sciences. MDCCXXXVIII [1738]."
3. "Atlas Russien: contenant une Carte Générale et dix-neuf Cartes particulieres de tout l'Empire de Russie et des Pays limitrophes construites conformément aux règles de la Geographie et aux dernières Observations. Par l'Académie Impériale des Sciences de St. Petersbourg. St. Petersbourg, 1745."
This was the first atlas published in Russia in the map department established by order of Peter the Great in the Academy of Sciences of St. Petersburg. It includes a general map of the Russian Empire and nineteen maps of provinces.