[19] Trans. (Izvestiya) Imp. Rus. Geog. Soc. (1889), p. 113.
[20] Die mittleren Erhebungsverhaltnisse der Erdoberfläche, pt. i., in Penck’s Geographische Abhandlungen, vol. v. (Vienna, 1891).
[21] Morphologie der Erdoberfläche, vol. i.
[22] The equivalent of the figures given in Superficie de l’Europe. A later measurement by Strelbitsky yielded a result equal to 2215 English miles.
[23] General von Tillo, in Transactions (Izvestiya) Imp. Rus. Geog. Soc. vol. xix. (1883), pp. 160-161.
[24] Dr Al. Bludau in Petermanns Mitteilungen (1898), pp. 185-187, has given new calculations of the areas of the basins of certain European rivers, namely, the Tagus, 31,250 sq. m.; Ebro, 32,810 sq. m.; Guadalquivir, 21,620 sq. m.; Po, 28,800 sq. m.; Guadiana, 25,810 sq. m.; and Jucar, 8245 sq. m.
[25] St Martin, Dict. de géog. univ.
[26] In other parts of this work areas of river-basins and lakes, and other measurements, may be observed to conflict in some degree with those given here. Various authorities naturally differ, both in methods of estimating and in standards of precision.
[27] Penck’s Geographische Abhandlungen, vol. v. pt. iv. (Vienna, 1894); noticed in Geog. Journ. vol. vi. p. 264.
[28] Including L. Pskov as well as the connecting arm known as Teploye.