When it shall be deemed advisable by the advisory committee of the district to enlarge the boundaries thereof, and the conditions mentioned in section 39-1639 apply to such enlarged territory, a petition for the enlargement of the district, signed by persons owning not less than twenty-five percent of the territory proposed to be added to the district, may be filed with the county clerk and thereupon the board shall proceed in all respects as provided in sections 39-1640 to 39-1643, so far as applicable.