The county of Gloucester, acting by and through the Gloucester county tunnel commission hereinafter provided for, is hereby authorized and empowered to provide for the construction, operation and maintenance of a vehicular tunnel under the Delaware river from a point in said county to a point opposite in the commonwealth of Pennsylvania, the location of such tunnel to be not less than ten miles from the existing bridge over the Delaware river between the city of Philadelphia, Pennsylvania, and the city of Camden, New Jersey, measured along the boundary line between the said commonwealth and the said state, and, to pay the cost of such tunnel, to issue tunnel revenue bonds of said county, payable solely from earnings.