...ambassador at Rome, whose acquaintance Sumner had made in Paris. The marquis was from that time a frequent visitor at Sumner's lodgings, and he continued for many years to live in Washington. Agassiz sailed in April, 1865, on his expedition to Brazil and the Amazon. Sumner entered heartily into the plans of the great naturalist. He wrote to him a God-speed just before he sailed, and received...