“I then introduced my son, and we were at once placed at our ease. His bright countenance expresses great benevolence, and from the fountains of his immense stores of knowledge a stream almost constant flowed for nearly an hour. He was not engrossing, but yielded to our prompting, whenever we suggested an inquiry, or alluded to any particular topic; for we did not wish to occupy the time with our own remarks any further than to draw him out. He has a perfect command of the best English, and speaks the language quite agreeably. There is no stateliness or reserve about him; and he is as affable as if he had no claims to superiority. His voice is exceedingly musical, and he is so animated and amiable that you feel at once as if he were an old friend. His person is not much above the middle size; he stoops a little, but less than most men at the age of eighty-two. He has no appearance of decrepitude; his eyes are brilliant, his complexion light; his features and person are round although not fat, his hair thin and white, his mind very active, and his language brilliant, and sparkling with bright thoughts. We retired greatly gratified, and the more so, as a man in his eighty-third year might soon pass away.”—Vol. ii. p. 318. Two years more had passed away, when we were honoured with an audience of the distinguished philosopher during our stay in Berlin. Age sits lightly upon his active head. Still full of unrecorded facts and thoughts, he labours daily in committing them to the written page,—for the grave, he tells you, waits him early now, and he must finish what he has to do before he dies. And yet he is as full at the same time of the discoveries and new thoughts of others, and as eager as the youngest student of nature in gathering up fresh threads of knowledge, and in following the advances of the various departments of natural science. And in so doing it is a characteristic of his generous mind to estimate highly the labours of others, to encourage the young and aspiring investigator to whatever department of nature he may be devoted, and to aid him with his counsel, his influence, and his sympathy. We found him congratulating himself on the possession of a power with which few really scientific men are gifted—that of making science popular—of drawing to himself, and to the knowledge he had to diffuse, the regard and attention of the masses of the people in his own and other countries, by a clear method, and an agreeable and attractive style in writing. “To make discoveries plain and popular is, perhaps, more difficult,” he said to us, “than to make the discoveries themselves.” And the feeling of the present time seems very much to run in sympathy with this sentiment. The power of diffusing is a gift perhaps as high, and often far more valuable to the community, than the power of discovering, and it should be esteemed and honoured accordingly. He