SIR: I have received your letters of the 18th and 21st November last. The exploring tour you propose has the sanction of the Government, provided the expenditure can be made out of the sum allotted your superintendency for Indian affairs, adding thereto one thousand dollars for that special purpose. The objects of this expedition are comprised under the five heads stated in your letter of the 18th of November, and which you will consider--with the exception of that part which relates to holding Indian treaties, upon which you will be fully instructed hereafter--as forming part of the instructions which may be given you by this Department. Should your reconnoissance extend to the western extremity of Lake Superior, you will ascertain the practicability of a communication between the Bad, or Burntwood River, which empties into the Lake, and the Copper, or St. Croix, which empties into the Mississippi, and the facility they present for a communication with our posts on the St. Peter's. The Montreal rivers will also claim your attention, with a view of establishing, through them, a communication between Green Bay and the west end of Lake Superior. To aid you in the accomplishment of these important objects, some officers of Topographical Engineers will be ordered to join you. Perhaps Major Long, now here, will be directed to take that route to join the expedition which he commands up the Missouri. In that event, a person acquainted with zoology and botany will be selected to accompany him. Feeling, as I do, great interest in obtaining a correct topographical, geographical, and military survey of our country, every encouragement, consistent with the means in my power, will be given by the Department. To this end, General Macomb will be ordered to afford you every facility you may require. I have, &c., J. C. CALHOUN. His Excellency, LEWIS CASS, Detroit, M. T. III. DEPARTMENT OF WAR, February 25, 1820. SIR: Mr. Schoolcraft, a gentleman of science and observation, and particularly skilled in mineralogy, has applied to me to be permitted to accompany you on your exploring tour upon Lake Superior. I have directed him to report to you, for that duty, under the belief that he will be highly useful to you, as well as serviceable to the Government and the promotion of science. You will furnish him with the necessary supplies and accommodation while employed, and every facility necessary to enable him to obtain a knowledge of the mineralogy of the country as far as practicable. I have, &c., J. C. CALHOUN. His Excellency, LEWIS CASS, Detroit. IV. DETROIT, March 10, 1820. SIR: I have the honor to acknowledge the receipt of your letter of the 17th ult., inclosing a copy of a letter from Giles Sanford & Co.