Sec. 15. Upon the expiration of the term of office of the present Factory Inspector, and upon the expiration of the term of office of each of his successors, the Governor shall, by and with the advice and consent of the Senate, appoint a Factory Inspector; and upon the expiration of the term of office of the present Assistant Factory Inspector, and upon the expiration of the term of office of each of his successors, the Governor shall, by and with the advice and consent of the Senate, appoint an Assistant Factory Inspector. Each Factory Inspector and Assistant Factory Inspector shall hold over and continue in office, after the expiration of his term of office, until his successor shall be appointed and qualified. The Factory Inspector is hereby authorized to appoint from time to time not exceeding sixteen persons to be Deputy Factory Inspectors, not more than eight of whom shall be women; and he shall have power to remove the same at any time. The term of office of the Factory Inspector and of the Assistant Factory Inspector shall be three years each. Annual salaries shall be paid in equal monthly instalments, as follows: To the Factory Inspector, three thousand dollars; to the Assistant Factory Inspector, two thousand five hundred dollars; to each Deputy Factory Inspector, one thousand two hundred dollars. All necessary travelling and other expenses incurred by the Factory Inspector, Assistant Factory Inspector, and the Deputy Factory Inspectors in the discharge of their duties shall be paid monthly by the Treasurer upon the warrant of the Comptroller, issued upon proper vouchers therefor. A sub-office may be opened in the city of New York at an expense of not more than one thousand five hundred dollars a year. The reasonable necessary travelling and other expenses of the Deputy Factory Inspectors while engaged in the performance of their duties shall be paid upon vouchers approved by the Factory Inspector and audited by the Comptroller.