Although the main body of the Austrians seems to be still concentrated between Peschiera and Verona, I should not wonder if they crossed the Mincio either to-day or to-morrow, with the object of occupying the heights of Volta, Cavriana, and Solferino, which, both by their position and by the nature of the ground, are in themselves so many fortresses. Supposing that the Italian army should decide for action--and there is every reason to believe that such will be the case--it is not unlikely that, as we had already a second battle at Custozza, we may have a second one at Solferino. That at the Italian headquarters something has been decided upon which may hasten the forward movement of the army, I infer from the fact that the foreign military commissioners at the Italian headquarters, who, after the 24th June had gone to pass the leisure of their camp life at Cremona, have suddenly made their appearance at Torre Malamberti, a villa belonging to the Marquis Araldi, where Lamarmora's staff is quartered. A still more important event is the presence of Baron Ricasoli, whom I met yesterday evening on coming here. The President of the Council was coming from Florence, and, after stopping a few hours at the villa of Cicognolo, where Victor Emmanuel and the royal household are staying, he drove to Torre Malamberti to confer with General Lamarmora and Count Pettiti. The presence of the baron at headquarters is too important an incident to be overlooked by people whose business is that of watching the course of events in this country. And it should be borne in mind that on his way to headquarters Baron Ricasoli stopped a few hours at Bologna, where he had a long interview with Cialdini. Nor is this all; for the most important fact I have to report to-day is, that whilst I am writing (five o'clock a.m.) three corps of the Italian army are crossing the Oglio at different points--all three acting together and ready for any occurrence. This reconnaissance en force may, as you see, be turned into a regular battle should the Austrians have crossed the Mincio with the main body of their army during the course of last night. You see that the air around me smells enough of powder to justify the expectation of events which are likely to exercise a great influence over the cause of right and justice--the cause of Italy. MARCARIA, July 3, Evening.