Some further developments have been made of the sentiments of the three allied powers, Austria, Russia, and Prussia, concerning the re-establishment of the Empire in France. It is represented that the late Minister of Austria was in favor of encouraging such a step, but that both the other powers concurred in saying that the accomplishment of it would be a "violation of the treaties of 1814 and 1815, inasmuch as those treaties have excluded for ever the family of Bonaparte from the government of France." Now, those treaties form the basis of the whole policy of Europe; and it is the duty of the powers to demand that they shall be respected by the President of the Republic himself in all their provisions, and particularly not to permit any infraction of them as to the point in question, which has reference to him personally. Nevertheless, the sovereigns of Prussia and Russia would not perhaps be disposed to refuse to recognize Louis Napoleon Bonaparte as Emperor of the French Republic--if that title were conferred on him by a new plébiscite--as had been spoken of but they should only recognize him as an elective Emperor, and for life, with only a status analogous to that of the former kings of Poland. If the two cabinets of St. Petersburg and Berlin consented to such a recognition, it was the utmost that it was possible to do; but, most certainly, beyond that point they should never go. At the same time, the cabinets formally declare, that they would only recognize the Emperor of the French Republic on the condition of his election being the result of the mode already announced (the plébiscite). They will not admit any other manner of re-establishing in France an imperial throne, even were it but for life; the two sovereigns being firmly resolved never to accept in the person of Louis Napoleon Bonaparte, any other than the supreme elective chief of the Republic, and to oppose by all the means in their power the pretension of establishing the actual President of the French Republic as Emperor, in the sense of an hereditary transmitter or founder of a Napoleonian dynasty. They add, that Louis Napoleon Bonaparte not being the issue of a sovereign or reigning family, can not become a real sovereign, or assimilate himself to reigning houses.----The pictures belonging to the late Marshal Soult were sold at auction on the 19th. The collection consisted of 157 paintings, and among them were many of the master-pieces of the old masters. The most celebrated was Murillo's 'Conception of the Virgin,' for which the chief competitors were the Emperor of Russia, the Queen of Spain, and the Director of the Louvre. It was bought by the latter at the enormous price of 586,000 francs,--or about $117,200. EASTERN AND SOUTHERN EUROPE.