to the treasurer of said corporation, until the six hundred thousand dollars subscribed for shall have been paid by the stockholders; and no scrip shall be delivered until satisfactory evidence of such payment is, from time to time, furnished to the governor and council; and provided, also, no scrip shall be delivered to the treasurer of said corporation until satisfactory evidence shall be furnished to the governor and council, that said corporation have expended in a reasonable manner, in excavating and completing said tunnel, and in grading, constructing and completing the line of road, a sum at least equal to the amount of all the preceding issues of scrip. SECT. 2. The preceding section of this act shall not be so constructed as necessarily to delay the opening of the road between Greenfield and Shelburne Falls, until after the completion of six thousand feet of tunnel; but whenever any portion of not less than three miles of said road shall have been graded between Greenfield and Shelburne Falls, as herein before provided, a portion of scrip, amounting to fifty thousand dollars, shall be delivered to the treasurer of the said company; and in case such payments shall have been previously made upon the road, the payments upon the completion of the third, fourth, fifth and sixth thousand feet of tunnel shall be reduced to thirty thousand dollars for each thousand feet of heading, and twenty thousand dollars for each thousand feet of tunnel of the required dimensions; but no portion of said scrip shall be delivered for any portion of said heading or tunnel, until the corresponding portion of the road shall have been graded as is herein before provided. SECT. 3. Whenever the treasurer of said company shall receive any of said scrip, he shall offer the scrip, 80 received, to the treasurer of the Commonwealth for sale; and if the treasurer of the Commonwealth shall so require, being thereunto authorized by law, the treasurer of said company shall sell and dispose of the same to the treasurer of the Commonwealth, at the fair market value thereof, to be determined by the governor and council. If the treasurer of the Commonwealth shall decide to buy as aforesaid, then the treasurer of the company shall forthwith pay, to the commissioners of the sinking fund, ten per cent. on the amount of the scrip so taken, as a sinking fund. If the treasurer of the Commonwealth shall decide not to buy, as aforesaid, then the treasurer of the company, within three months after the receipt of any of said scrip, shall pay to the commissioners of the sinking fund, ten per cent. on the amount of the scrip so received, as a sinking fund. After the whole of said road is open for use, twenty-five thousand dollars annually, shall be set apart from the income of said road, and paid to said commissioners; and the whole thereof shall be added to said sinking fund, and shall be managed; invested and appropriated, as is or shall be provided by law in relation thereto.