Be it enacted by the people of the State of Illinois, represented, in the General Assembly, That the commissioners heretofore appointed by law to superintend the construction of the necessary improvements to the navigation of the Little Wabash river, or a majority of said commissioners, are hereby authorized and required to adjust the accounts of John Groves, on a contract for the erection of a lock at Robinson’s mill down on the said River; and to execute to the said Groves, upon ascertaining what balance, if any, is due to him on his said contract, a certificate setting out that such balance does so remain due, and upon production of said certificate to the commissioners for the sale of saline lands at Equality, the said Groves shall be entitled to purchase land from the said commissioners, to the amount of the sum stated to be due by the certificate aforesaid, at the rate per acre provided by law, or he may purchase a less quantity if he prefer; and the said commissioner shall endorse on the said certificate the number of acres so purchased by the said Groves, and file the same in his office. And the said commissioner shall issue and grant to the said Groves certificates of purchase in the usual form, and make a spicial entry on his books, explaining the transaction; and the certificate of the commissioners first named to the said Groves, shall be taken as payment of such lands as may be so purchased by him; according to the amount purchased