Mr. Mickley was always happy to join in these impromptu musical assemblies, when occasion offered, although performing music was one of the few things which he never succeeded in doing well. He invariably played the viola on these occasions,--perhaps, as Schindler hints about Beethoven, because indifferent playing on the viola is not so noticeable as on other instruments. As was to have been expected from so pronounced an antiquarian, he had small sympathy for modern music. He even rebelled against the gentle innovations of Mendelssohn, contending, not without an approach to accurate judgment, that Haydn and Mozart had completely covered the field of chamber-music. While in the midst of numerous and always congenial pursuits during his long life, quartette-playing remained a favorite pastime of very many days in very many years. Mr. Mickley's intellect was so many-sided and so evenly balanced that it is difficult to name his predominant bias. It is very nearly safe, however, to say that this was his historic faculty. In the writings, still chiefly unprinted, which were left behind him, he was at once the most minute and the most compact of historians. Emerson never condensed his rare thoughts into smaller compass, not even in his "English Traits," than Mr, Mickley has condensed his facts and observations. There is a small pamphlet extant, the manuscript of which was read by him in 1863 on the occasion of the centennial anniversary of a noted Indian massacre in Northampton County, Pennsylvania, where several of his ancestors perished. It contains historic material enough for a volume. To indicate his early passion for amassing reliable data, the same sketch shows that a portion of its facts had been obtained, while he was still a boy, from then aged eye-witnesses of the affair, nearly fifty years before its story was thus put into permanent shape. He mastered the Swedish language, after having passed his seventieth year, chiefly that he might write a correct history of the first settlement of Swedes on the Delaware River below Philadelphia. At the age of seventy-two he spent several months in Stockholm, the capital of Sweden, and while there placed himself in communication with every prominent librarian of the country, besides scholars in Denmark, Holland, and Germany. He personally inspected a great mass of documents and ancient volumes. Yet the result of all this is contained in a manuscript of less than thirty large folio pages, literally crowded with invaluable data. This was read before the Historical Society of the State of Delaware in 1874. It has never been put in type, and is almost wholly made up of material which has no existence elsewhere in the English language.