A few hours after the death of the Czar Nicholas, his son, heir, and successor, Alexander II., ascended the throne and the officers of the imperial house took the oaths of allegiance. The new Emperor in his manifesto to his subjects says--as his father devoted himself incessantly for the welfare of his Empire, “so do we also on ascending the throne of Russia, and of Poland and Finland, inseparable from it, take a solemn oath before God to regard the welfare of our Empire as our only object. May Providence, which has selected us for so high a calling, be our guide and protector, that we may maintain Russia on the highest standard of power and glory, and in our person accomplish the incessant wishes and views of Peter, of Catharine, of Alexander, and of our father. May the zeal of our subjects assist us therein. We invoke and command the oath of allegiance to us, and to the heir to the throne, our son Nicholas Alexandrowitsch.” The new Sovereign of Russia is thirty-seven years of age, his figure tall and commanding, his features fine, with a Grecian profile, an expression of kindness, a step light and gracefully noble. Previous to his accession, he held the posts of Commander-in-Chief of the Corps de la Garde, and of the Grenadiers; presided over the Military School, and was Curator-in-Chief of the Military Hospital of Tchesmé, and holds the command of the Lancers, the Carabiniers of Erivan, &c. He was initiated, at an early age, into the affairs of the Empire by the Emperor his father; he was present at all the councils; he was invested with situations which gave him frequent opportunities of rendering himself useful to the army, and pleasing to the youth of the schools. Whenever the Emperor Nicholas quitted the capital, he left the supreme direction of the Government to his son; in short, he had taken the utmost pains to prepare him to become his successor. The new Emperor is very popular in Russia--he is beloved and esteemed by the people. He will not exercise the great authority of his father, for he does not inherit either his hauteur or his inflexibility. He will rather please, as the Emperor Alexander I. did, by his mildness and his affability; and between the uncle and the nephew there is a very great similarity of character in numerous ways. The new Empress is also highly spoken of, and her elevated judgment and her conciliating manners are much extolled. It is thought she will exercise a salutary influence over the Emperor.