Early in 1859, the Emperor of Austria began to threaten Sardinia with 100,000 men, demanding that she should disarm, which was refused. The Emperor of the French showed himself ready to sustain Victor Emanuel in his position; and then the Emperor of Austria made an effort to gain time by an artifice, and pressed a powerful army on to the frontiers. With surprising promptitude, Louis Napoleon sent a very large force into Piedmont, partly across Mount Cenis and partly by water to Genoa, availing himself of the facilities offered by the railroads and steam vessels, and armed with the most improved military weapons and implements of modern warfare. Then commenced one of the most important and sanguinary conflicts of modern times, and one most decisive of results in favor of Italian liberty. The armies on both sides were very large and powerful, and included many of the chiefs, officers, and soldiers who had been trained in Africa and the Crimea, as well as in the European wars ten and twelve years preceding. The sudden and rapid advance of the Austrians was checked by the vigorous stand made by the Piedmontese, and the still more rapid movements of the troops from France. We have not room to give all the details of the battles which ensued, and with which the public are acquainted. The service which our hero rendered in it was of the utmost importance; and not only fully justified the high reputation he had long enjoyed, but raised him to an eminence proportioned to the magnitude of the immense military operations in which he acted a leading, and we might say almost the decisive part.