In the summer of 1801 he embarked at Portsmouth and set out on this expedition. His absence from England lasted more than four years, during which period the southern, eastern, and northern coasts of New Holland, and the southern part of Van Diemen's Land were thoroughly explored; and he arrived in Liverpool, in the month of October, 1805, enriched with a collection of dried plants amounting to nearly 4000 species, a large proportion of which were not only new to science, but likewise exhibited extraordinary combinations of character and form. Immediately on his arrival in England, Brown was appointed librarian of the Linnean Society, of which he had been elected an associate in 1798. The materials which he had been indefatigable in collecting during this voyage, and the vast store of facts and observations in relation to their structure and affinities which he had accumulated, opened out to him new views upon a multitude of botanical subjects, which he was enabled by his position in the Linnean Society to enlarge, and to perfect, and ultimately to lay before the world in a series of masterly publications, which at once stamped upon him the character of the greatest and most philosophical botanist that England had ever produced. In 1810 appeared the first volume of his 'Prodromus Floræ novæ Hollandiæ et Insulæ Van Diemen.' This important work, together with his memoirs on Proteaciæ and Asclepiadeæ, which immediately followed, and his 'General Remarks, Geographical and Systematical, on the Botany of Terra Australis,' appended to the 'Narrative of Captain Flinder's Voyage,' published in 1814, by displaying in the most instructive form the superior advantages of the Natural System, gave new life to that system, which had hitherto found little favour in France, and speedily led to its universal adoption. A series of memoirs followed the above works, chiefly in the Transactions of the Linnean Society, or in the appendices to various books of travel and survey, which gave fuller and more complete development to his views upon almost every department of botanical science, and induced the illustrious Humboldt not only to confer upon Brown the title mentioned at the beginning of this memoir, but also to designate him as the "Glory and Ornament of Great Britain."[5]