Section 7
SEC. 7. Said grantee shall file his written acceptance of this franchise with the Secretary of Public Works and Communications within one hundred and twenty days from the date when he obtains the certificate required by Section one of this Act, and shall commence work under the supervision of the city engineer, in accordance with the plan specifications, and estimates previously approved by the Public Service Commission, within six months time from and after the date of filing such acceptance, unless prevented by act of God or force majeure, usurped or military power, martial law, riot, or civil commotion or other inevitable cause, and shall complete the system and have the same in operation within eighteen months from the date of such acceptance, and shall thereafter maintain a first-class water system and furnish first-class service to the public and to private consumers: Provided, That in consideration of the franchise hereby granted, the grantee shall pay quarterly to the city treasury of the city above named, three per centum of the gross earning of his business during the first fifteen years, and two per centum during the remaining ten years of the life of this franchise.