This has been a day of much interest among us and of no little excitement--a day of changes and reorganization. An exciting rumor was bandied from man to man this morning, that General Hooker was about to be relieved from the command of the grand army; and the day was only partly spent when the strange rumor resolved itself into the astounding truth. The facts which led to this result may not be perfectly understood among us, but appear to be about as follows: On discovering that the enemy had actually invaded the Northern States, General Hooker requested the authorities to send him all the forces which could be spared from General Heintzelman's command in and about the Defenses of Washington. This was done. But, having crossed the Potomac, General Hooker visited Harper's Ferry with its strong garrison, and immediately urged upon the Government the importance of placing this force also under his command. Upon this subject there sprang up a sharp controversy between Hooker and Halleck. The latter rejoined to the former in these words: "Maryland Heights have always been regarded as an important point to be held by us, and much expense and labor incurred in fortifying them. I cannot approve of their abandonment, except in case of absolute necessity." General Hooker's reply to this shows him to have been in the right, and to have comprehended the relative importance of the position in question: "I have received your telegram in regard to Harper's Ferry. I find ten thousand men here in condition to take the field. Here they are of no earthly account. They cannot defend a ford of the river; and, so far as Harper's Ferry is concerned, there is nothing of it. As for the fortifications, the work of the troops, they remain when the troops are withdrawn. This is my opinion. All the public property could have been secured to-night, and the troops marched to where they could have been of some service. Now they are but a bait for the Rebels, should they return. I beg that this may be presented to the Secretary of War, and his Excellency, the President." Receiving no direct reply to this announcement, and goaded by the pressure of fast-moving events, our General yielded to do what many of us heartily condemn, by sending the following message: SANDY HOOK, MD., June 27, 1863. _Major-General H. W. Halleck, General-in-Chief_: My original instructions require me to cover Harper's Ferry and Washington. I have now imposed upon me, in addition, an enemy in my front of more than my numbers. I beg to be understood respectfully, but firmly, that I am unable to comply with this condition, with the means at my disposal, and earnestly request that I may at once be relieved from the position I occupy. JOSEPH HOOKER, _Major-General_.