IN FRONT OF YORKTOWN, Saturday, April 12, 1862.

The New York Times

Friday night I availed myself of Capt. GRIFFIN's hospitality, and spread my rubber blanket on the floor of his tent, and put a pair of boots under my head for a pillow. This was a pretty good beginning for a night's rest. But unfortunately my bed-clothing gave out at this point. The Captain and his estimable Lieutenant, KINGSBURT, (may they never lack boots or blankets in this world of any other!) saw my quandary, and each contributed a quilt from his own bed to perfect my lodging. One folded beneath me, and one spread over my wearied frame, made my outfit complete and with a felling of contentment and dolce far niente, far beyond anything I had for a long time enjoyed on feathers, I resigned myself to rest and slumber. The other camp-lodgers had rolled themselves in their blankets and gone to the ground before me. I had prudently waited to see how the things was done, so that I might not betray any awkwardness in my bed-making. At last we were all in place, with our feet to the camp-stove in the centre, the light extinguished, and sleep creeping slowly over the group. Just then a sharp volley of rifle-shots was heard, too significant to pass unheeded. Capt. GRIFFIN chuckled with the satisfaction of an inborn artillerist, as he exclaimed: "There they go, give it to 'em boys," -- adding in explanation to the rest of us that the rebels had come out of their intrenchments in the day to plant a battery in the peach-orchard that lay between their camp and ours, but that BERDAN's Sharpshooters had driven them away; that doubtless they were trying to finish their work under cover of night, and our sharpshooters in the peach-orchard were driving them away. Feeling sure that this work would not be neglected, we resigned our cause into the hands of BERDAN's corps, and soon were fast asleep.

By daylight in the morning we were all awakened by the most terrific braying of a thousand mules in the camps around -- the most plaintive monotones, mingled with the most 'harsh' and startling snorts. But all meant one thing only, the want of fodder -- for they had been living eight days on two days' rations. No wonder they whinnied and cried, as if each had lost his respected father. The first one of our party that rose next morning brought us all to our feet and to the door of the tent, in camp deshabille, with the exclamation that a balloon was loose in the upper air. It floated majestically, and rose rapidly some miles to the south and east of us. We were startled by the announcement made soon after, that it bore aloft Gen. FITZ JOHN PORTER, commanding the division that we were in, that he was alone, and the rope that bound the balloon to the earth had broken. The balloon continued to ascend after we learned this, and as it was apparently too high already for observations on land, we did not doubt, the news, and began to fear greatly lest the luckless air-ship should land our General among the rebels. Soon we saw, however, that the General was master of his position in the air, as he generally is of that on land; for he had evidently opened the valve and let out a large quantity of gas, and the flaccid bag began to descend rapidly to the earth. Our next fear was that he would not know how to moderate his descent, and be shattered by his precipitate fall. There was reason to fear this, as the event proved; for we learned about an hour afterward that he had come down so violently as to hurt one of his sides for some time.

This camp incident being over, we dressed ourselves, and addressed ourselves to the duty of getting breakfast. We had as good a meal as many in far more favorable circumstances. Among our delicacies were fried oysters, caught fresh from their beds in York River, and hot corn cakes. These oysters were part of the wealth of Old Virginia, on the catching of which, by Yankees, Gov. WISE proposed to place a tax, to help support the broken-down treasury of the State. Let him consider that the party of Capt. GRIFFIN's tent owe him an abolus for Friday's breakfast, which the Captain will pay in Spartan coin on demand.

Breakfast being disposed of, my host informed me that there was a point on York River bank, a mile or so from our camp, from which I could get a good view of Yorktown and Gloucester Point, on the opposite shore; and I gladly accepted his pilotage to visit the spot. It was considered a very little bit hazardous, as the point was in easy range of the enemy's shells. Whether for this reason or not, I do not know, but the Surgeon of the Griffin Battery volunteered to accompany us. I thought he might be useful, as well as an agreeable member of the party. We headed two creeks in our ride before we could make our desired position, which was a a large frame farm-house on the shore of York River,not more than a mile and a half from the most formidable redoubt of the Yorktown fortifications, and not more than half a mile from our camp, though we had ridden three miles to reach it. On nearing the house,we were directed by our leader to approach singly, and to tie our horses in separate places. A "solitary horseman" may be an important feature in a novel of Mr. JAMES, but it takes several men and horses to be worth a shot from a battery. The farm-house belongs to a Mr. FARMHOLT. He had taken refuge in Yorktown, from which we inferred his rebel politics. But he had his wife on the place, or she had chosen to stay to look after the few contrabands roaming idly about. Mayhap, I thought to myself, she will be able to pick up, occasionally, a little National news and communicate it to her husband. In possible nocturnal visits to the old farm. To be sure, we had two pickets on the spot, but pickets are sometimes not sharp enough to see everything. Mrs. F. had removed from the mansion, and taken up her quarters in a negro hut a hundred yards distant, giving as a reason, the fear that the house would be shelled from Yorktown, or by our gunboats.

From the second-story windows of this house, by the aid of glasses, we got views of the immense earthworks of Yorktown. They seem to be wonderfully strong. The walls are high and thick, surrounded by a moat, and having sally-ports and draw[???]. It seemed impossible that any army could carry the fortifications by assault. They must be reduced by siege guns and mortars -- making them, by the flight of hot shot and shells over the ramparts, too hot to hold their defenders. There are the usual defences of masked batteries and rifle-pits outside of the works. Heavy 18 1 or 24-pound columbiads, placed en barbatte, command the river and shore approach, while a water battery can rake the waters in any direction. Yorktown stands on a bluff thirty or forty feet high, apparently. Gloucester Point opposite, is about on the same level. It has lately been crowned with strong earthworks, and has on the beach, immediately opposite the Yorktown wharf, a beautifully constructed water battery with seven embrasures. The river just here is only about three-quarters of a mile wide. Gloucester was the first place seized by Gen. WASHINGTON, in his celebrated siege and capture of the British army, at Yorktown, in the Revolution. It was a part of Gen. MCCLELLAN's plan to have seized it also: but the remarkable change of the limits of his Department, and the diversion of the troops to another field, after he went forth to consummate his campaign, is said here to have thwarted his purpose. With our glasses, from the Farmholt House, we could easily trace the old earthwork built by the British, now covered with the smooth, green rod. We could see the soldiers and the contrabands lazily lounging on the sand-bags of the water battery, or loitering on the wharf, gazing down the river at four of our gunboats, lying like black watch-dogs below. There were two schooners at the wharf, that had apparently just been discharged, whether of men or food we could not tell. There were, in all, twenty-five schooners and other water-craft in sight, the majority of which had no doubt been used to bring reinforcements of rebels to Yorktown.

While we were intently studying these strongholds, a heavy gun was fired. I saw the flash, and the magnificent whirl of the white eddying smoke high in air, and in a moment the roar, of the rude monster burst upon the ear. We did not see where the shot fell, but concluded it was a little safer to go outside of the old wooden mansion, if a shell was at all likely to burst into it. We therefore sought our horses as cautiously as we left them, and took leave of the pleasing rebel landscape -- not, however, until I had tried to make a crayon sketch of it, which I turned over to that talented and enthusiastic young artist, ARTHUR LUMLEY, of the New-York Illustrated News, to be elaborated into a presentable picture for the patrons of that magazine. Do yourself the pleasure to buy a copy of the next number, and judge of the merits of our joint skill.

On our return to camp, we visited a rebel fort, small in size but formidable in structure, that it rebels had built during the Winter, but abandoned on the approach of our army. It was doubtless part of the line of defences by which they expected to prevent any approach of hostile forces to the rear of Yorktown -- to the ground now occupied by our army. It was a square earthwork, covering about an acre of ground, surrounded by a broad, deep ditch, full of water, and having an entrance in the rear by a draw, or rather a pole bridge, that could in a moment be displaced.

It was 2 o'clock before we got back to camp from our reconnoissance, and as I had determined to go to Ship Point that night, ten miles over that dreadful road that I have once before described, I had barely time to call over at Gen.MCCLELLAN's new camp, just moved up to this admirable region, to find all hands industriously engaged in pitching their tents. They were greatly elated on their removal from the fields of mud below. While here, I saw a dispatch just received from Gen. WOOL, announcing the exploit of the rebel fleet in capturing the schooners near Newport's News. This intelligence increased my anxiety to get off to Old Point, for we all considered another battle of the iron monsters imminent, and I trusted to be there to see it.

How I traveled again over that road -- how I sought transportation on the ocean steamer Daniel Webster, from Ship Point to Fortress Monroe -- how kindly Capt. J.H. BLETHEN assisted my endeavors for the sake of the NEW-YORK TIMES -- all this, and more, must be reserved for another letter. YORK.