SECT. 1. The treasurer of the Commonwealth is hereby authorized and instructed to issue scrip, or certificates of debt, in the name and in behalf of the Commonwealth, and under his signature and the seal of the Commonwealth, for the sum of two millions of dollars, which may be expressed in the currency of Great Britain, and may be payable to the bearer thereof in London, and bearing an interest of five per cent. per annum, payable semi-annually in London, on the first days of April and October; or the said scrip may be issued in federal currency, payable in Boston, as the directors of the Troy and Greenfield Railroad Company shall elect when they apply for each and every issue of said scrip, with warrants for the interest attached thereto, signed by the treasurer; which scrip or certificates, in the currency of Great Britain, shall be redeemable in London, and those in the federal currency, at Boston, at the end of thirty years from the date thereof, and the same shall bear date on the first day of April or October which shall precede the issue of each portion of said scrip; and all such scrip shall be countersigned by the governor of the Commonwealth, and be deemed a pledge of the faith and credit of the Commonwealth, for the redemption thereof; and the treasurer of the Commonwealth, under the conditions hereinafter provided, shall deliver the same to the treasurer of the Troy and Greenfield Railroad Company for the purpose of enabling the said company to construct a tunnel and railroad under and through the Hoosac Mountain, in some place between the "Great Bend" in Deerfield River, in the town of Florida, at the base of Hoosac Mountain on the east, and the base of the western side of the mountain, near the east end of the village of North Adams, on the west.