In our article: V. E. Plyushchev, V. M. Amosov, M. B. Varfolomeev, “Synthesis and Some Properties of the Lower Crystalline Hydrates of the Perrhenates of Yttrium, Lanthanum, and Lanthanoids,” published in *DAN*, vol. 150, No. 1, 1963, in Table 1 (p. 107), we erroneously placed values of the refractive indices relating not to lower but to other crystalline hydrates of perrhenates, whose properties will be published in another communication.

CORRECTION

In our article: V. E. Plyushchev, V. M. Amosov, M. B. Varfolomeev, “Synthesis and Some Properties of the Lower Crystalline Hydrates of the Perrhenates of Yttrium, Lanthanum, and Lanthanoids,” published in DAN, vol. 150, No. 1, 1963, in Table 1 (p. 107), we erroneously placed values of the refractive indices relating not to lower but to other crystalline hydrates of perrhenates, whose properties will be published in another communication.

In fact, in Table 1 the following data should be given (from top to bottom):

Column 4 \((N_p)\): 1.717; 1.717; 1.720; 1.720; 1.723; 1.728; 1.728; 1.694; 1.694; 1.697; 1.697; 1.700; 1.700; 1.700; 1.688.

Column 5 \((N_g)\): 1.733; 1.733; 1.733; 1.733; 1.733; 1.736; 1.736; 1.702; 1.702; 1.710; 1.710; 1.712; 1.712; 1.712; 1.701.

Column 6 \((N_m)\): 1.702; 1.702; 1.705; 1.705; 1.705; 1.695.

On p. 108 (sixth line from the top), instead of “...or when evaporating them...” it should read: “...in the process of evaporating them to dryness.”

V. E. Plyushchev, V. M. Amosov, M. B. Varfolomeev