It appeared to me possible that the report on the eclipses of the moon made by de l'Isle to the St. Petersburg Academy of Sciences might be traced up among the archives of that society. In searching for information on this point it was learned from Mr. O. Fassig, librarian of the Signal Office, that among the unpublished manuscripts in the Pulkova library, St. Petersburg, were a number by de l'Isle. A list of the manuscripts of M. de l'Isle was compiled and published in 1844 by the distinguished astronometer O. Struve, and among the number is one entitled: "Observations pour la longitude du Kamchat, d'ou se conclut aussi de Tobolsk. 1729, MSS." {221} It was reasonable, in view of de l'Isle's statements in 1738, to suppose that this is the report made to the Academy by him as soon as the observations were furnished him. I had hoped to present with this sketch definite information on this point, since a kinsman of the collator of the manuscripts (I refer to the very distinguished representative of Russia to the United States, M. de Struve) most courteously offered his valuable mediation in the matter. Unfortunately, I have as yet no further information, but I expect a communication as to the contents of the MSS. at an early day. Criticising the memoir of de l'Isle of 1752, the Russian officer ridicules the author for speaking of Kamshatka as a town, but he adds:[7] "It is certain likewise that M. Bering and his lieutenant, M. Tschirikow [quoting from de l'Isle's Memoir of 1752], had, in the years 1728 and 1729, observed at Kamschatka two eclipses of the moon; but that by these observations M. de l'Isle was enabled to determine the longitude of this most eastern part of Asia, with such precision that the same had been confirmed in the second expedition, by precise observations of the satellites of Jupiter is what I cannot well conceive. Mr. de l'Isle himself intimates that Messieurs Bering and Tschirikow were not provided with astronomical instruments. They observed both these eclipses by the help, not of pendulums, but of their watches, without being able to know whether they went right or wrong; which makes it almost incredible that a determination based on these two eclipses should exactly agree with that deduced from the observations of Jupiter's satellites." [Footnote 7: "Une Lettre," Berlin, p. 19.] The officer, from his own account, served with Bering. In the introduction to "Une Lettre" he says: