All tribal funds arising under on , included in the fund “Indian Money, Proceeds of Labor”, shall, on and after , be carried on the books of the Treasury Department in separate accounts for the respective tribes, and all such funds with account balances exceeding $500 shall bear simple interest at the rate of 4 per centum per annum from .section 155 of this titleJune 13, 19301930-06-13July 1, 19301930-07-01July 1, 19301930-07-01