Among the improvements introduced on this map may be specified, the correction of the shores of the Okhotsk Sea, and Gulf of Penjina, the correcter location of the mouth of the Anadyr river and its estuary, the introduction of the results of the voyages of Gvosdeff, Bering and Chirikoff to the northwest coast of America, and a multitude of details relating to northeastern Siberia. The island of St. Deomid (Diomede) is not represented though its name appears on the 65th parallel in Bering Strait. The island may have been on the original map and carelessly omitted by Jefferys' engraver on his copy. Among the errors, or rather mistaken hypotheses of others, which are suggested in this map by dotted lines, are the extension westward to 174° E. of Greenwich, of the peninsula of Aliaska which is also given a wholly uncalled-for width; and the northward extension of the coast on each side of Bering Strait. In the former case the cartographer was misled by the errors of the map of Bering and Chirikoff's last voyage and rumors reported by other navigators; and in the second case he followed Bering in adopting an erroneous position and exaggerated form for the coast eastward from Koliuchin Bay, due to the uncorrected sketches of the Cossacks and traders. The northern extension of the American coast opposite, was purely hypothetical and for this Müller must be held responsible. Many of the western Aleutians are exaggerated in size and erroneous in position but the chart of Bering's last voyage, and the exaggerated reports of the hunters who followed him, must be held responsible for this, in the main. The work in which this chart appears is largely derived from Müller's "Sammlung russische geschichte," St. Petersburg, 1758, vol. iii, Parts I-III (cf. antea). The first edition is entitled, according to bibliographies: "Voyages from Asia to America for completing the discoveries of the northwest coast of America. A summary of voyages made by the Russians on the frozen sea. From the high Dutch of S[taatsrath]. Muller by T. Jefferys. London: T. Jefferys, 1761." lxvi, 76 pp. 4°, with four maps. The second edition which is that referred to in this paper is entitled "Voyages from Asia to America, for completing the discoveries of the northwest coast of America. To which is prefixed, a summary of the Voyages made by the Russians on the Frozen Sea, in search of a northeast passage. Serving as an explanation of a map of the Russian discoveries, published by the Academy of Sciences at Petersburgh, [etc.] London: T. Jefferys, 1764," viii, 120 pp. 4°, four maps.