first time—the examination of which convinced Harvey that the Orkney plant was only a variety of Chrysymenia rosea (Lomentaria rosea Thuret). Mrs Gatty became a useful ally in the collecting of seaweeds, and a valued friend; Harvey's influence is seen in her British Seaweeds; published in 1863.
The year 1851 saw the completion of the Phycologia Britannica, and he at once set to work on his Nereis Boreali-Americana, published in three parts in the Smithsonian Contributions to Knowledge—a work of 550 quarto pages containing an account of all the known species of North American Algae, and 50 coloured plates, lithographed as usual with his own hand—a fine piece of work, and one which has not yet been superseded. This was a time of strenuous labour, for already he was planning a still more extended foreign tour; but he found time in the autumn of 1852 for a trip to Switzerland with Sir William Hooker and other friends.
In August, 1853, Harvey set out on the most extended scientific expedition of his life. So far his collecting had been done in Europe, South Africa, and North America. Now he was to visit the Indian Ocean and Australasia, and to investigate their seaweed flora, as yet but little known.
A short stay was made in Egypt, and a sea-shore ramble at Aden yielded Padina pavonia and a few other seaweeds, but otherwise he made no stop till Ceylon was reached. There he travelled a good deal, but seaweed collecting was not so successful as he had hoped. Some of the places explored proved unproductive, and the prevalence of the monsoon rendered collecting difficult or impossible. But the last three weeks, spent at Belligam Bay and Point de Galle, yielded excellent results, and he proceeded to Singapore en route for Albany, with a collection of about 5000 specimens of Algae.
The first work in Australia was done in the extreme southwest. Here he gathered seaweeds assiduously in King George's Sound, but the ground proved rather poor, though one welcome storm brought him a rich harvest, of which he preserved 700 specimens in one day. He moved on to Cape Riche, to the eastward, travelling through the bush on foot, and thus making intimate acquaintance with the interesting vegetation as well as