He had long desired to visit America, when he realized this wish in 1846 by an arrangement with the Lowell Institute of Boston, where he gave a series of lectures, afterwards repeated in various cities. So attractive did he find the fauna and flora of America, and so vast a field did he perceive here for his individual studies and instruction, that he returned the following year. In 1848 the Prussian government, which had borne the expenses of his scientific mission,--a cruise along our Atlantic coast to study its marine life,--released him from further obligation that he might accept the chair of geology in the Lawrence Scientific School of Harvard University. His cruises, his explorations, and his methods, combined with his attractive personality, gave him unique power as a teacher; and many of his biographers think that of all his gifts, the ability to instruct was the most conspicuous. He needed no text-books, for he went directly to Nature, and did not believe in those technical, dry-as-dust terms which lead to nothing and which are swept away by the next generation. Many noted American men of science remember the awakening influence of his laboratories in Charleston and Cambridge, his museum at Harvard, and his summer school at Penikese Island in Buzzard's Bay, Massachusetts, where natural history was studied under ideal conditions. It was here that he said to his class:--"A laboratory of natural history is a sanctuary where nothing profane should be tolerated." Whittier has left a poem called "The Prayer of Agassiz," describing "The isle of Penikese Ranged about by sapphire seas." Just as he was realizing two of his ambitions, the establishment of a great museum and a practical school of zoölogy, he died, December 14th, 1873, at his home in Cambridge, and was buried at Mount Auburn beneath pine-trees sent from Switzerland, while a bowlder from the glacier of the Aar was selected to mark his resting-place. Agassiz was greatly beloved by his pupils and associates, and was identified with the brilliant group--Emerson, Longfellow, Holmes, and Lowell,--each of whom has written of him. Lowell considered his 'Elegy on Agassiz,' written in Florence in 1874, among his best verses; Longfellow wrote a poem for 'The Fiftieth Birthday of Agassiz,' and Holmes 'A Farewell to Agassiz' on his departure for the Andes, whose affectionate and humorous strain thus closes:-- "Till their glorious raid is o'er, And they touch our ransomed shore! Then the welcome of a nation, With its shout of exultation, Shall awake the dumb creation, And the shapes of buried aeons Join the living creatures' paeans, While the mighty megalosaurus Leads the palaeozoic chorus,-- God bless the great Professor, And the land its proud possessor,-- Bless them now and evermore!"