Section 9. As soon as possible after the recording of the description, plan and estimate as provided in section seven, the commissioners shall request the clerk to call a meeting of the district for the purpose of deciding upon a method of financing such improvements in accordance with this or the following section; provided, that the commissioners may in their discretion insert an article covering this question in the warrant for the meeting called to organize the district and the district at said meeting or any adjournment thereof may decide upon a method of financing. Any action under this chapter which involves expenditure by the district shall require a vote of proprietors representing a majority in interest both in acreage and value of the area included in the district. The commissioners shall, if the district so votes, petition the county commissioners of the county where the greater part of the land lies, annexing a certified copy of the petition under section five and of the determination of the board thereon, and a statement of the estimated expense of the proposed improvements and shall request the county commissioners to vote to pay in the first instance the total expense involved in making the improvements approved by the board, and the said county commissioners may so vote. To defray any expense incurred by said county commissioners under such vote, the county treasurer, with the approval of the county commissioners, may issue bonds or notes of the county to an amount not exceeding such expense, payable in such period, not exceeding twenty-five years from their dates of issue, as the county commissioners may determine. Such bonds or notes shall be signed by the county treasurer and countersigned by a majority of the county commissioners. The county may sell the said securities at public or private sale upon such terms and conditions as the county commissioners may deem proper, but not for less than their par value. The first payment on account of the principal may, if the county commissioners so decide, be deferred for not more than five years after the date of issue of the bonds or notes, but such bonds or notes shall be subject to the provisions of chapter thirty-five except as otherwise provided herein. Payments on account of principal and interest shall be made by the county and repaid to the county by the district.