A sum not exceeding $7,000,000 for the construction of the toll road from a point on the Massachusetts-New Hampshire boundary in the town of Seabrook to a point in the city of Portsmouth and a sum not exceeding $14,300,000 for the construction from said point in the city of Portsmouth to a point in the vicinity of the city of Rochester is hereby appropriated as hereinafter provided for the purposes of carrying into effect the provisions of this subdivision.