The Secretary of the Interior is hereby authorized, under such rules and regulations as he may prescribe, to grant to any qualified applicant a prospecting permit which shall give the exclusive right to prospect for chlorides, sulphates, carbonates, borates, silicates, or nitrates of sodium, in lands belonging to the United States for a period of not exceeding two years: Provided, That the area to be included in such a permit shall not exceed two thousand five hundred and sixty acres of land in reasonably compact form.
(Feb. 25, 1920, ch. 85, §23,
1928-Act Dec. 11, 1928, struck out "and directed" after "authorized", "dissolved in and soluble in water, and accumulated by concentration, in lands belonging to the United States for a period not exceeding two years," after "nitrates of sodium", and last proviso which read "Provided further, That the provisions of this section shall not apply to lands in San Bernardino County, California."