R. M. WHITNEY, Esq: Dear Sir--I observe an invitation in yesterday's Journal, for me to call at, or send to, your office, for some information which you have to impart. For reasons which I shall have the pleasure of expressing to you hereafter in person, I am anxious to preserve my _incognito_, for the present, even with my nearest friends; and this consideration will prevent my _calling_. I am also at a loss to know how to _send_; but if you will drop me a few lines in the letter box of the Post-office, I shall not fail to receive them. Very truly, &c., VALLEY FORGE. _September 23d, 1842._ Please direct to "Ambrose Anderson, Philadelphia." R. M. WHITNEY, Esq., Dear Sir,--I am favored with your note, refering me to General Cadwalader's pamphlet, which you inform me has been abstracted from the Philadelphia Library. I have access to _material_, far beyond any thing in importance and value which could possibly be obtained by General Cadwalader; nevertheless the _abstraction_ of his pamphlet is a circumstance which I will not fail to turn to good account. The gentleman to which I so often refer, in my communications as the revolutionary soldier who has furnished me with information, is a near relative of mine, who knew Gen. Joseph Reed thoroughly. I shall continue my communications from time to time; and you may rely upon my giving you nothing, which does not admit of literal substantiation. Among other letters which I have, are several from "George Clymer," (whom you mention in your note,) which hit the nail on the head. Will you permit me the liberty of suggesting a continuance of your vigorous editorials upon Stephen Girard? The word "finessed" in my last, your compositor has transformed into _finified_. Respectfully &c., VALLEY FORGE. Sept. 25, 1842. REUBEN M. WHITNEY, Esq., Dear Sir,--I am afraid that, in copying Sergt. Kemp's first letter, I have made an error of date, on which account I am glad my communication has not appeared to-day, as it gives me an opportunity of correction. I am anxious to avoid even the slightest mistake in my communications. The letter is dated "June 23rd, 1778." I am not certain that I did not so transcribe it; but if I did not, be good enough to make the correction. I particularly wish you would _italicise_ my interrogatory to Reed relative to his grandfather's correspondence with General Wayne. There is a _point_ in it which _he_ will fully understand, and which will give him more uneasiness than all else. I intend reserving my extracts from that correspondence for the very last.