It is the last degree--at the next step we rise into heroism. In the afternoon we were relieved by a Pennsylvania company, and as we retired in full sight of the rebels, the rascals yelled at us, and gave us several volleys, from which it is wonderful that every man escaped. That evening we moved to the extreme rear, into Fort Washington, on the bank of the river in front of Harrisburg. Here it was said our advance work was over, and we were promised comfortable quarters and rest. Any one nowadays can see a camp, but only one who has seen it can understand how picturesque it is. The night scene at Harrisburg was beautiful in the extreme. Behind us slept the city--we guarded it in front, and the river rolled between. The moonlight, illuminating a most exquisite scenery, between the foliage gave glimpses of that placid stream, and shone upon the tents and bayonets of some six thousand men within the formidable works; the expiring fires sent up wreaths of smoke; grim guns looked over the ramparts down the gentle slope in front and up the beautiful Cumberland Valley; and only the occasional call of the sentry for the corporal of the guard broke the serene stillness. Here were our friends of the 8th, and here we regained our knapsacks. Many of them had been 'gone through,' and everything 'won.' The 56th and 22d New York, the 23d and 18th Brooklyn, besides others, were encamped inside. Here we were sworn into the United States service for thirty days from the 17th June. On Wednesday, July 1st, all our prospect of camp life, with its regularity of drill, inspection, and, above all, of rations, was dashed by orders to move in the morning to Carlisle. General Knipe, riding through camp, was asked where he was going to take us. 'Right into the face of the enemy,' said he. 'Hi, hi!' shouted the men. So away we went again. I was detailed to guard baggage, and remained, loading wagons, &c., subject to the quartermaster, and went on in the cars to Carlisle, where, on the evening of the 3d, I joined the regiment when it came in. Since we left Carlisle the rebels had been there and burned the barracks. They had shelled the town the night before, and the 37th had had a sharp skirmish with them.