The superintendent shall have power to place any girl under the age of eighteen years at any employment for account of the institution or the girl employed, and receive and hold the whole or any part of her wages for the benefit of the girl less the amount necessary for her board and keep, and may also, with the consent of any girl over fourteen years of age, and the approval of the secretary endorsed thereon, execute indentures of apprenticeship, which shall be binding on all parties thereto. In case any girl so apprenticed shall prove untrustworthy or unsatisfactory, the superintendent may permit her to be returned to the school, and the indenture may thereupon be canceled. If such girl shall have an unsuitable employer, the superintendent may, with the approval of the secretary, take her back to the school, and cancel the indenture of apprenticeship. All indentures so made shall be filed and kept in the school. A system may also be established, providing for compensation to girls for services rendered, and payments may be made from time to time, not to exceed in the aggregate to any one girl the sum of twenty-five dollars for each year of service.