The Admiralty, with the approval of Her Majesty in Council, may from time to time make free grants of land part of the lands vested in them by virtue of this Act, and grants of money, for the erection of buildings and providing conveniences for places of worship, residence of ministers, education of children, or other public purposes (so that any such grant of land do not include any right to the minerals under the land granted, or comprise more than two acres in any one parish).