The owner of a bus line to whom a certificate is issued within ten days after the issuance of such certificate, and as a condition precedent to the exercise of any rights granted by such certificate, shall make, execute and deliver unto the city and shall at all times during the life of the certificate, maintain in full force and effect, a good and sufficient bond, issued by a corporate surety authorized by law to engage in the surety business in the state, in the aggregate principal sums as shall be determined and estimated by the council at the time of the issuance of the certificate, equaling the amount that will be due the city for its percentage of gross receipts from the operation of such bus line for a period not to exceed six months. Each such bond shall, before becoming effective, be approved as to surety and sufficiency by the city attorney. Each such bond shall be conditioned that the principal shall well and truly observe and faithfully perform the provisions of his certificate, this chapter and the resolution authorizing the same pertaining to the obligation to compensate the city by a percentage of gross receipts and that in the event a breach is made in such condition then and in that event, the whole amount of the penal sum therein named shall be forfeited to the city. (Ord. 73 NCS §14; prior code §24.50.)