The general treasurer may, from time to time in writing, authorize the deputies to do any and all things required of the general treasurer, and the acts of the deputies so authorized shall have the same legal effect as if done by the general treasurer, provided, however, that in no case shall the deputies have power to sign the bonds, notes or other evidences of indebtedness of the state, and provided, further, that the authorization may be terminated at the pleasure of the general treasurer.