SEC. 3. That all lands in those portions of the United States where irrigation is necessary to agriculture, which can be redeemed by irrigation and for which there is accessible water for such purpose, not otherwise utilized or lawfully claimed, sufficient for the irrigation of three hundred and twenty acres of land, shall, for the purposes set forth in this act, be classed as irrigable lands. SEC. 4. That it shall be lawful for the requisite number of persons, as designated in section one of this act, to select from the public lands designated as irrigable lands in section three of this act, for the purpose of settling thereon, an amount of land not exceeding eighty acres to each person; but the lands thus selected by the persons desiring to organize an irrigation district shall be in one continuous tract, and the same shall be subdivided as the regulations and by-laws of the irrigation district shall prescribe: _Provided_, That no one person shall be entitled to more than eighty acres. SEC. 5. That whenever such irrigation district shall be organized the recorder of such district shall notify the register and receiver of the land district in which such irrigation district is situate, and also the Surveyor-General of the United States, that such irrigation district has been organized; and each member of the organization of said district shall file a declaration with the register and receiver of said land district that he has settled upon a tract of land within such irrigation district, not exceeding the prescribed amount, with the intention of residing thereon and obtaining a title thereto under the provisions of this act.