DEAR SIR;-- * * * * * What has been already said on the subject of Casa Calvo, Yrujo, Miranda, is sufficient, and that these should be seriously brought up again argues extreme weakness in Cavallos, or a plan to keep things unsettled with us. But I think it would not be amiss to take him down from his high airs as to the right of the sovereign to hinder the upper inhabitants from the use of the Mobile, by observing, 1st, that we claim to be the sovereign, although we give time for discussion. But 2d, that the upper inhabitants of a navigable water have always a right of innocent passage along it. I think Cavallos will not probably be the minister when the letter arrives at Madrid, and that an eye to that circumstance may perhaps have some proper influence on the style of the letter, in which, if meant for himself, his hyperbolic airs might merit less respect. I think too that the truth as to Pike's mission might be so simply stated as to need no argument to show that (even during the suspension of our claims to the eastern border of the Rio Norte) his getting on it was mere error, which ought to have called for the setting him right, instead of forcing him through the interior country. [Sullivan's letter.] His view of things for some time past has been entirely distempered. Cathcart's, Ridgeley's, Navour's, Degen's, Appleton's, Lee's, and Baker's letters, are all returned. I salute you with great affection and respect. TO GENERAL DEARBORNE. MONTICELLO, May 25, 1808.