In taking a calm retrospect of the dispositions made by NAPOLEON on the night of the 15th of June, we become strongly impressed with a conviction, that to the laxity of those dispositions, to the absence which they indicated of that energetic perseverance and restless activity which characterised the most critical of his operations in former Wars, may, in a very great degree, be attributed the failure of the Campaign on the part of the French. The great advantages derived by NAPOLEON from the result of his operations during the 15th, have been already set forth; but of what avail were those advantages to him, if he neglected the requisite measures for effectually retaining them within his grasp; or if, having secured them, he hesitated in following them up with the promptitude and energy which their complete development demanded of him? His position, if judged by that of his most advanced forces, was all that could be desired; but, by fatally neglecting to concentrate the remainder of his troops in the immediate support of that advance, the important advantages which such a position held forth were completely neutralized. Doubtless the troops required rest; but, if one portion required it more than another, it was that which now lay most in advance: they had performed the longest march, and had withstood, in addition, the whole brunt of the action; so there was no reason whatever why the remainder of the French Army should not have been so far advanced as to afford direct support to the important position taken up by the leading Divisions: that which had been so successfully effected by the heads of the Columns, might have been attained with infinitely greater ease and security by the masses which followed. And even supposing that serious impediments stood in the way of the full accomplishment of this concentration, such as the usual delays occasioned by the lengthening out of the Columns of March, to what did they amount in comparison with so many brilliant instances of what had been overcome by the noble and heroic efforts of a French Army headed by NAPOLEON? Had it even required some sacrifice, which at the most could only have consisted in the temporary diminution of strength, by the loss of stragglers on the march, what was this when placed in the balance with the fulfilment of the grand design of NAPOLEON's invasion of Belgium--preventing the junction of the Allied Armies, and overthrowing them in detail?