On July 21 -- the day when he set out to reconnoiter New York -- he addressed the following autograph letter (whose original is now in the possession of the editor of this History) to Brigadier-General David Forman1 at Monmouth X. J. : Head Quarters, Dobbs Ferry, 21st July, 1781. Dear Sir:-- When I request your particular Care of the enclosed, it is necessary that 1 should inform you in the fullest confidence, and under the strictest injunctions of seeresy, that the Count de Grasse may be shortly expected with his whole fleet from the West Indies. Whether he will first appear off the Hook or the Capes of Virginia is uncertain-- You will be pleased immediately, upon the receipt of this, to employ proper persons to keep a look out. The Moment that a Fleet of heavy Ships is discovered you will dispatch an express to me, and as soon as you can ascertain whether they are friends or Foes, another; If they prove to be the former you will oblige me by going on board the Admiral and presenting the letter herewith. I have mentioned you to him as a Gentleman in whom lie may place the fullest confidence. That intelligence may be communicated from you to me with the utmost dispatch you will be pleased to take some of the militia Horse into pay and station them at such distances between Monmouth and Dobbs Ferry that they may perform the ride in twelve or fifteen hours. The Horsemen need not know the particular purpose for which they are stationed, but they must be ordered never to be a moment absent from their stages except when upon duty. The expense attending those and the persons who keep a look out I will be answerable for. You will be so good as to give me by the return of this, or in the chain which you shall establish, the present situation, number, strength, and station of the Enemy's Ships -- and as particular information of this kind may lie very useful and consequential to me and to our French Allies -- 1 beg you will continue to keep me informed from time to time of any alterations which take place, either respecting their increase or decrease of numbers anil strength, their different positions, and particular stations, within or without the Hook, that we may lose no advantages or suffer any misfortune for want of perfect information of the Enemy's strength, Positions, or movements -- I amDear withSirrespect, Your most obedient servant, G.