Murray's guide will save me the trouble of telling you what this little and dirty hole of Marcaria is like. The river Oglio runs due south, not far from the village, and cuts the road which from Bozzolo leads to Mantua. It is about seven miles from Castellucchio, a town which, since the peace of Villafranca, marked the Italian frontier in Lower Lombardy. Towards this last-named place marched this morning the eleventh division of the Italians under the command of General Angioletti, only a month ago Minister of the Marine in Lamarmora's Cabinet. Angioletti's division of the second corps was, in the case of an attack, to be supported by the fourth and eighth, which had crossed the Oglio at Gazzuolo four hours before the eleventh had started from the place from which I am now writing. Two other divisions also moved in an oblique line from the upper course of the above-mentioned river, crossed it on a pontoon bridge, and were directed to maintain their communications with Angioletti's on the left, whilst the eighth and fourth would have formed its right. These five divisions were the avant garde of the main body of the Italian army. I am not in a position to tell you the exact line the army thus advancing from the Oglio has followed, but I have been told that, in order to avoid the possibility of repeating the errors which occurred in the action of the 24th, the three corps d'armee have been directed to march in such a manner as to enable them to present a compact mass should they meet the enemy. Contrary to all expectations, Angioletti's division was allowed to enter and occupy Castellucchio without firing a shot. As its vanguard reached the hamlet of Ospedaletto it was informed that the Austrians had left Castellucchio during the night, leaving a few hussars, who, in their turn, retired on Mantua as soon as they saw the cavalry Angioletti had sent to reconnoitre both the country and the borough of Castellucchio. News has just arrived here that General Angioletti has been able to push his outposts as far as Rivolta on his left, and still farther forward on his front towards Curtalone. Although the distance from Rivolta to Goito is only five miles, Angioletti, I have been told, could not ascertain whether the Austrians had crossed the Mincio in force. What part both Cialdini and Garibaldi will play in the great struggle nobody can tell. It is certain, however, that these two popular leaders will not be idle, and that a battle, if fought, will assume the proportions of an almost unheard of slaughter. GENERAL HEADQUARTERS OF THE ITALIAN ARMY, TORRE MALIMBERTI, July 7, 1866.