If from such returns it appears that more than two-thirds of the votes cast at such election held pursuant to the provisions of this chapter were in favor of and assented to the incurring of such indebtedness, then the board may, by resolution, at such time or times as it deems proper, provide for the form and execution of such bonds and for issuance of any part thereof, and may sell or dispose of the bonds so issued at such times or in such manner, either for cash in lawful money of the United States or its equivalent, as it may deem to be to the public interest.