IN our recent communication1 on this acid, melting point 293°, the empirical formula C27H44O3 was adopted in preference to C30H48O3 originally proposed by Kariyone and Kurono2. Following upon a more detailed examination of this compound and its degradation products, in conjunction with the results of molecular-weight determinations according to the method of Ruzicka and Furter3 with oleanolic and betulic acids as the standard, we have now established that eburicoic acid has the formula C30H48O3 (found: C, 78.9; H, 10.5; mol. wt. (by titration), 459–462; C30H48O3 requires C, 78.9; H, 10.5 per cent; mol. wt., 457). A re-investigation of the following derivatives described in the earlier note1 affords results in complete agreement with the C30-formula: O-acetyl eburicoic acid (m.p. 256-257°; found: C, 77.0; H, 10.0. C32H50O4 requires C, 77.0; H, 10.1 per cent), methyl eburicoate (m.p. 140–141°; found: C, 79.1; H, 10.5. C31H50O3 requires C, 79.1; H, 10.7 per cent), methyl O-acetyl -eburicoate (m.p. 153–154°; found: C, 77.5; H, 10.3. C33H52O4 requires C, 77.3; H, 10.2 per cent), and p-nitrobenzyl eburicoate (m.p. 150.5°; found: C, 74.8; H, 9.2; N, 2.5. C37H53O5N requires C, 75.0; H, 9.0; N, 2.4 per cent).