LETTER--No. 37.

FORT GIBSON, ARKANSAS TERRITORY .

Since the date of my last Letter at Pensacola, in Florida, I travelled to New Orleans, and from thence up the Mississippi several hundred miles, to the mouth of the Arkansas; and up the Arkansas, 700 miles to this place. We wended our way up, between the pictured shores of this beautiful river, on the steamer " Arkansas," until within 200 miles of this post; when we got aground, and the water falling fast, left the steamer nearly on dry ground. Hunting and fishing, and whist, and sleeping, and eating, were our principal amusements to deceive away the time, whilst we were waiting for the water to rise. Lieutenant Seaton, of the army, was one of my companions in misery, whilst we lay two weeks or more without prospect of further progress -- the poor fellow on his way to his post to join his regiment, had left his trunk, unfortunately, with all his clothes in it; and by hunting and fishing in shirts that I loaned him, or from other causes, we became yoked in amusements, in catering for our table-in getting fish and wild fowl; and, after that, as the "last kick" for amusement and pastime, with another good companion by the name of Chadwick, we clambered up and over the rugged mountains' sides, from day to day, turning stones to catch centipedes and tarantulas, of which poisonous reptiles we caged a number; and on the boat amused ourselves by betting on their battles, which were immediately fought, and life almost instantly taken, when they came together.

In this, and fifty other ways, we whiled away the heavy time : but yet, at last we reached our destined goal, and here we are at present fixed. Fort Gibson is the extreme south-western outpost on the United States frontier; beautifully situated on the banks of the river, in the midst of an extensive and lovely prairie ; and is at Present occupied by the with regiment of United States infantry, heretofore under the command of General Arbuckle, one of the oldest officers on the frontier, and the original builder of the post.

Being soon to leave this little civilized world for a campaign in the Indian country, I take this opportunity to bequeath a few words before the moment of departure. Having sometime since obtained permission from the Secretary of War to accompany the regiment of the United States dragoons in their summer campaign, I reported myself at this Place two months ago, where I have been waiting ever since for their organization. -- After the many difficulties which they have had to encounter, they have at length all assembled--the grassy plains are resounding with the trampling hoofs of the prancing warhorse -- and already the hills are echoing back the notes of the spirit-stirring trumpets, which are sounding for the onset. The natives are again "to be astonished", and I shall probably again be a witness to the scene. But whether the approach of eight hundred mounted dragoons amongst the Camanchees and Pawnees, will afford me a better subject for a picture of a gaping and astounded multitude, than did the first approach of our steamboat amongst the Mandans, &c., is a question yet to be solved. I. am strongly inclined to think that the scene will not be less wild and spirited, and I ardently wish it; for I have become so much Indian of late, that my pencil has lost all appetite for subjects that savour of tameness. I should delight in seeing these red knights of the lance astonished, for it is then that they shew their brightest hues -- and I care not how badly we frighten them, provided we hurt them not, nor frighten them out of sketching distance. You will agree with me, that I am going farther to get- sitters, than any of my fellow-artists ever did; but I take an indescribable pleasure in roaming through Nature's trackless wilds, and selecting my models, where I am free and unshackled by the killing restraints of society; where a painter must modestly sit and breathe away in agony the edge and soul of his inspiration, waiting for the sluggish calls of the civil. Though the toil, the privations, and expense of travelling to these remote parts of the world to get subjects for my pencil, place almost insurmountable, and sometimes painful obstacles before me, yet I am encouraged by the continual conviction that I am practicing in the true School of the Arts; and that, though I should get as poor as Lazarus, I should deem myself rich in models and studies for the future occupation of my life. Of this much I am certain -- that amongst these sons of the forest, where are continually repeated the feats and gambols equal to the Grecian Games, I have learned more of the essential parts of my art in the three last years, than I could have learned in New York in a life-time.

The landscape scenes of these wild and beautiful regions, are, of themselves, a rich reward for the traveller who can place them in his portfolio: and being myself the only one accompanying the dragoons `for scientific purposes, there will be an additional pleasure to be derived from those pursuits. The regiment of eight hundred men, with whom I am to travel, will be an effective force, and a perfect protection against any attacks that will ever be made by Indians. It is composed principally of young men of respectable families, who would act, on all occasions, from feelings of pride and honour, in addition to those of the common soldier.

The day before yesterday the regiment of dragoons and the 7th regiment of infantry, stationed here, were reviewed by General Leavenworth, who has lately arrived at this post, superseding Colonel Arbuckle in the command.

Both regiments were drawn up in battle array, in fatigue dress, and passing through a number of the manoeuvres of battle, of charge and repulse, &c., presenting a novel and thrilling scene in the prairie, to the thousands of Indians and others who had assembled to witness the display. The proud and manly deportment of these young men remind one forcibly of a regiment of Independent Volunteers, and the horses have a most beautiful appearance from the arrangement of colours. - Each company of horses has been selected of one colour entire. There is: a company of. bays, a company of blacks, -one of whites, one of sorrels, one of greys, one of cream colour, &c. &c., which render the companies distinct, and the effect exceedingly pleasing. This regiment goes out under the command of Colonel Dodge, and from his well tested qualifications, and, from the beautiful equipment of the command, there can be little doubt but that they will do credit to themselves and an honour to their country I so far as honours can be gained and laurels can be plucked from their wild stems in a savage country. The object of this summer's campaign seems to be to cultivate an acquaintance with the Pawnees and Camanchees. These are two extensive tribes of roaming Indians. who, from their extreme ignorance of us, have not yet recognized the United States in treaty,:and have struck frequent blows on -- our frontiers and plundered our traders who are traversing their country. For this I cannot so much blame them, for the Spaniards are gradually advancing upon them on one side, and the Americans on the other, and fast destroying the furs and game of their country, which God gave them as their only wealth and means of subsistence. This movement of the dragoons seems to be one of the most humane in its views, and I heartily hope that it may prove so in the event, as well for our own sates as for that of the Indian. I can see no reason why we should march upon them with an invading army carrying with it the spirit of chastisement. The object of Government undoubtedly is to effect a friendly meeting with them, that they may see and respect us, and to establish something like a system of mutual rights with them. To penetrate their country with the other view, that of chastising them, even with five times the number that are now going, would be entirely futile, and perhaps disastrous in the extreme. It is a pretty thing (and perhaps an easy one, in the estimation of the world) for an army of mounted men to be gaily prancing over the boundless green fields of the West, and it is so for a little distance -- but it would be well that the world should be apprised of some of the actual difficulties that oppose themselves to the success of such a campaign, that they may not censure too severely, in case this command should fail to accomplish the objects for which they were organized.

In the first place, from the great difficulty of organizing and equipping, these troops are starting too late in the season for their summer's campaign, by two months. The journey which they have to perform is a very long one, and although the first part of it will be picturesque and pleasing, the after part of it will be tiresome and fatiguing in the extreme. As they advance to the West, the grass (and consequently the game) will be gradually diminishing, and water in many parts of the county not to be found.

As the troops will be obliged to subsist themselves a great part of the way, it will be extremely difficult to do it under such circumstances, and at the same time hold themselves in readiness, with half-famished horses and men nearly exhausted, to contend with a numerous enemy who are at home, on the ground on which they were born, with horses fresh and ready for action. It is not probable, however, that the Indians will venture to take advantage of such circumstances; but I am inclined to think, that the expedition will be more likely to fail from another source : it is my opinion that the appearance of so large a military force in their country, will alarm the Indians to that degree, that they will fly with their families to their hiding-places amongst those barren deserts, which they themselves can reach only by great fatigue and extreme privation, and to which our half-exhausted troops cannot possibly follow them. From these haunts their warriors would advance and annoy the regiment as much as they could, by striking at their hunting parties and cutting off their supplies. To attempt to pursue them, if they cannot be called to a council, would be as useless as to follow the wind; for our troops in such a case, are in a country where they are obliged to subsist themselves, and the Indians being on fresh horses, with a supply of provisions, would easily drive all the buffaloes ahead of them; and endeavor, as far as possible, to decoy our troops into the barren parts of the country, where they could not find the means of subsistence.

The plan designed to be pursued, and the only one that can succeed, is to send runners to the different bands, explaining the friendly intentions of our Government, and to invite them to a meeting. For this purpose several Camanchee and Pawnee prisoners have been purchased from the Osages, who may be of great service in bringing about a friendly interview.

I ardently hope that this Plan may succeed, for I am anticipating great fatigue and privation in the endeavor to see these wild tribes together; that I may be enabled to lay before the world a just estimate of their manners and customs.

I hope that my suggestions may not be truly prophetic; but I am constrained to say, that I doubt very much whether we shall see anything more of them than their tails, and the sites of their deserted villages.

Several companies have already started from this place; and the remaining ones will be on their march in a day or two. General Leavenworth will accompany them 200 miles, to the mouth of False Washita, and I shall be attached to his staff. Incidents which may occur, I shall record. Adieu.