To meet the expenses incurred under the provisions of sections 40:37-96 to 40:37-174 of this title in addition to the sum of money received from benefit assessments as herein provided and otherwise, the board of chosen freeholders of the county shall from time to time, on the requisition of the park commission, borrow money in the name and on the credit of the county, by issuing bonds of the county to a sum in the aggregate not exceeding two million five hundred thousand dollars.