The Secretary of the Interior is authorized, in his judgment and discretion, to employ for consultation purposes on important reclamation work ten consulting engineers, geologists, appraisers, and economists, at rates of compensation to be fixed by him, but not to exceed $50 per day for any engineer, geologist, appraiser, or economist so employed: , That the total compensation paid to any engineer, geologist, appraiser, or economist during any fiscal year shall not exceed $5,000: , That notwithstanding the provisions of any other Act, retired officers of the Army or Navy may be employed by the Secretary of the Interior as consulting engineers in accordance with the provisions of this section.ProvidedProvided further