The retirement board shall supervise the collection of assessments on all permanent firemen accepting the provisions hereof and the payment of retirement benefits and other compensation hereunder. To carry out the purposes hereof the board may make all manner of reasonable rules and regulations not inconsistent with the provisions of this chapter. The board shall employ a secretary at a salary to be approved by it, whose duty it shall be to keep a record of all its proceedings and to perform such administrative duties as it may direct. The expenses of administration of this chapter shall be paid out of the retirement fund hereinafter provided for.