THORWALDSEN.--The Danish Government some time since sent Mr. Thiele, a competent person, to Rome, for the purpose of collecting every thing that could be obtained toward a history of the life and works of this illustrious sculptor, whose early life is so obscure that even the date and place of his birth are unknown, as well as the employment he made of the first years that he was in Italy. Mr. Thiele has found a number of casks in the cellars of the Tomati Palace at Rome, filled with letters, addressed to Thorwaldsen, and among them a long and constant correspondence between him and his mother, who lived part of the time in Denmark and part of the time in Iceland, her native country. It seems that Thorwaldsen had the habit of preserving his papers, even to the most trifling, by flinging them confusedly into a cedar box in his room; when that was full they were emptied into the casks where they have now been found; these casks were not noticed when all the other contents of the palace were removed to Copenhagen. Whatever is interesting in these papers will, of course, be published. Mr. Thiele has also discovered in the same cellar the model of a bas-relief by the same great artist, representing the Muses dancing by Helicon. It will be added to the collection of his works at Copenhagen. * * * * * THE artist HEIDEL has published at Berlin a series of Eight Illustrations to Goethe's Iphigenia. He aims in them to preserve unmixed the spirit of antique art, and thus to prove that the Germans are the true successors of the Greeks. The subjects of his designs are:--The Fall of Tantalus; the Departure of Agamemnon; the Sacrifice of Iphigenia; the Death of Agamemnon; the Death of Clytemnestrae; the Flight of Orestes; the Meeting of Orestes and Iphigenia; and the Return of Iphigenia. The designs are praised by the German critics. They say that in beholding the Flight of Orestes, pursued by the Furies, who dare not enter the sacred temple of Apollo where he seeks refuge, one imagines that he hears the fearful chanting of a chorus of AEschylus. * * * * * A NEW ART called _Metallography_ has been discovered by Nicholas Zack, a lithographer at Munich, by means of which designs that have hitherto been engraved on wood can be put directly upon metal, and in such a manner as to be printed from. The plate is prepared beforehand, and the artist draws his design upon it with a pencil or a needle. Without any further labor, by means of the preparation alone, the plate will be ready for printing. Worn-out plates may be restored with very little expense. * * * * * A BOOKSELLER of Munich has published Albert Duerer's sketches from the prayer-book of Emperor Maximilian I., with the original text, colored initials, and an introduction. Price eight thalers, about $6,00. * * * * *