170.041.  Physical education supplies and equipment — certain districts may raise funds for. — The board of each seven-director school district which employs thirty or more teachers and also employs a supervisor of physical education or supervisor of health under section 168.171 may raise and expend funds to carry out the purpose of that section and for the purchase of books, printed matter, apparatus, including weighing scales, instruments and other necessary appliances and supplies as are designated by the commissioner of education.