An Act for explaining and rendering more effectual two Acts, one made in the twelfth year of the reign of Queen Anne, intituled, An Act for providing a publick reward for such person or persons as shall discover the longitude at sea : and the other in the twenty sixth yea of the reign of King George the Second, intituled, An Act to render more effectual an Act made in the twelfth year of the reign of Her late Majesty Queen Anne, intituled, An Act for providing a publick reward for such person or persons as shall discover the longitude at sea, with regard to the making experiments of proposals made for discovering the longitude; and to enlarge the number of commissioners for putting in execution the said Act.