The aspect of affairs in Europe during the last summer, and especially between Spain and England, gave reason to expect a favorable occasion for pressing to accommodation the unsettled matters between them and us. Mr. Carmichael, our charge d'affaires at Madrid, having been long absent from his country, great changes having taken place in our circumstances and sentiments during that interval, it was thought expedient to send some person, in a private character, fully acquainted with the present state of things here, to be the bearer of written and confidential instructions to him, and at the same time to possess him in full and frequent conversations of all those details of facts and topics of argument which could not be conveyed in writing, but which would be necessary to enable him to meet the reasonings of that Court with advantage. Colonel David Humphreys was therefore sent for these purposes. An additional motive for this confidential mission arose in the same quarter. The Court of Lisbon had on several occasions made the most amicable advances for cultivating friendship and intercourse with the United States. The exchange of a diplomatic character had been informally, but repeatedly, suggested on their part. It was our interest to meet this nation in its friendly dispositions and to concur in the exchange proposed. But my wish was at the same time that the character to be exchanged should be of the lowest and most economical grade. To this it was known that certain rules of long standing at that Court would produce obstacles. Colonel Humphreys was charged with dispatches to the prime minister of Portugal and with instructions to endeavor to arrange this to our views. It happened, however, that previous to his arrival at Lisbon the Queen had appointed a minister _resident_ to the United States. This embarrassment seems to have rendered the difficulty completely insurmountable. The minister of that Court in his conferences with Colonel Humphreys, professing every wish to accommodate, yet expresses his regrets that circumstances do not permit them to concur in the grade of chargé d'affaires, a grade of little privilege or respectability by the rules of their Court and held in so low estimation with them that no proper character would accept it to go abroad. In a letter to the Secretary of State he expresses the same sentiments, and announces the appointment on their part of a minister _resident_ to the United States, and the pleasure with which the Queen will receive one from us at her Court. A copy of his letter, and also of Colonel Humphreys's giving the details of this transaction, will be delivered to you.