§ 4704. Powers and duties of board. The board of managers of such school shall be responsible for the operation and maintenance of the school; employ a superintendent and such teachers and assistants as may be required for the operation and maintenance of the school when authorized so to do by the board of supervisors or other governing elective body of the county; fix the compensation of such superintendent, teachers and assistants within the amount made available therefor by the said board or body; prescribe rules and regulations for the management of the school and for the purpose of carrying into effect the object thereof; provide for the detention, maintenance and instruction of all children who are admitted to the school.