Section 87A. The director of standards, upon the written request of the colonel of state police, shall appoint any of those persons appointed under section ten of chapter twenty-two C as weighers and measurers of motor vehicles and trailers and of the loads of such vehicles and trailers. Before entering upon their duties, such weighers and measurers shall be sworn. Such officers shall serve as long as they have the powers of police officers or until said colonel shall in writing request the director to revoke such appointment.