An institution in the nature of a bank, formed or established for the purpose of receiving deposits of money, for the benefit of the persons depositing, to accumulate the produce of so much thereof as shall not be required by the depositors, their executors or administrators, at compound interest, and to return the whole or any part of such deposit, and the produce thereof, to the depositors, their executors or administrators, deducting out of such produce so much as shall be required for the necessary expenses attending the management of such institution, but deriving no benefit whatever from any such deposit or the produce thereof. Grant. Banks, 546; Johnson v. Ward, 2 111. App. 274; Com. v. Reading Sav. Bank. 133 Mass. 16. 19, 43 Am. Rep. 495; National Bank of Redemption v. Boston, 125 U. S. 60, 8 Sup. Ct 772, 31 L. Ed. 689; Barrett v. Bloomfield Sav. Inst., 64 N. J. Eq. 425, 54 Atl. 543.