as to affect his health, led him into increased researches in his favourite scientific field. In 1851 he became Lecturer on Botany in the Marischal College and University of Aberdeen, and while holding this office he devoted much of his time to zoological studies, making many elaborate investigations among the lower forms of animal life, and publishing various papers on the "Polyzoa and Sertularian Zoophytes of Scotland." Among these papers we may mention, "Notes on some Scotch Zoophytes and Polyzoa," published in the "Annals of Natural History," vol. ix. (1852) pp. 403, &c.; and "On the Character of the Sertularian Zoophytes."*

On the resignation of Mr. Hincks, Professor of Natural History in Queen's College, Cork, which took place in 1853, Wyville Thomson was appointed his successor; but his stay at Cork was short, for the professorship of Mineralogy and Geology in the Queen's College, Belfast, becoming vacant in 1854 by Professor McCoy's acceptance of a chair in the University of Melbourne, Thomson was transferred from Cork to fill his place.

Thus at a very early age his academical teaching extended over all the great departments of Natural History, a training admirably adapted both to foster speculation in the higher generalizations of scientific inquiry, and to impart that accumulated knowledge of facts which is the best safeguard against undue rashness in such speculations.

During his career at Belfast he continued to contribute many valuable papers on Natural History and cognate subjects to the scientific journals. As Professor of Mineralogy and Geology he had specially to deal with the extinct forms of life, as they appear in their fossil state; but his zeal in the study of the lower forms of living animals was undiminished, and the special excellence of his method of investigation was that he treated the two departments of inquiry as one, making the living organisms of the present illustrate the fossil remains of pre-historic times, and the fossil organisms of the past throw light upon the history of those of our times.

It is to Professor Wyville Thomson that the Queen's College at Belfast owes the origin of its now admirable Museum of Natural History, and he did much during his professorship there to enrich it. The zoologica collection which he added to it is especially worthy of notice, and is the fruit of many years' labour.

Up to this time it had been almost universally believed by naturalists that there was a limit of depth in the ocean, below which animal life did not extend. The generally accepted opinion on the subject was that of Edward Forbes, who divided the sea into four zones, according to its

* Brit. Assoc. Reports, 1852, pt. 2, p. 78.

depth and the nature of its known inhabitants.

These were-1st, the

littoral zone, between high and low-water marks; 2nd, the laminarian zone, between low-water mark and a depth of fifteen fathoms; 3rd, the coralline zone, from the fifteen fathom line to a depth of fifty fathoms; and 4th, the zone of deep sea corals, extending from the fifty fathom line to an unknown lower depth. With regard to the last of these, Forbes says, "In this region, as we descend deeper and deeper, its inhabitants become more and more modified, and fewer and fewer, indicating our approach towards an abyss where life is either extinguished or exhibits but few sparks to mark its lingering presence."

There were not a few ascertained facts pointing in an opposite direction, so far as regards the existence of animal life at remote depths; but men of science clung to the theory that it was impossible for such life to be maintained under more than a certain amount of superincumbent pressure, and hence they argued that the lower regions of the sea were barren of living organisms. Yet in 1819 Sir John Ross, the Arctic navigator, had stated in the published account of his voyage of discovery, that when sounding in Baffin's Bay in the preceding autumn he obtained a depth of 1,000 fathoms; that the bottom consisted of soft mud in which there were worms; and that "entangled in the sounding line at the depth of 800 fathoms was found a beautiful Caput Medusa." More recently Sir James Clark Ross, dredging in the Antarctic regions in 270 fathoms of water reported that corallines, Flustre, and a variety of invertebrate animals came up in the net, showing an abundance of animal life. "It was interesting," he says, "amongst these creatures to recog nize several that I had been in the habit of taking in equally high northern latitudes, and although contrary to the general belief of naturalists, I have no doubt that from however great a depth we may enabled to bring up the mud and stones of the bottom of the ocean we shall find them teeming with animal life." Again, in 1860, in the course of the soundings taken by H.M.S. Bulldog, between Cape Farewell and Rockall, thirteen star-fishes came up from 1,260 fathoms "convulsively embracing" the portion of the sounding line which had been paid out in excess of the ascertained depth, and allowed to rest a sufficient time at the bottom to permit of their attaching themselves to it.

be

A yet more convincing proof of the existence of animal life at great depths was obtained in 1860, when the telegraphic cable between Sardinia and Bona was raised for repair, and a portion of it which had been lying for two years in 1,200 fathoms was found by Professor Fleeming Jenkin to be covered with living animals. "I regard this observation of Mr. Fleeming Jenkin," says Professor Wyville Thomson, "as having

afforded

"Voyage of Discovery and Research in the Southern and Antarctic Regions, 18391843." London, 1849, p. 47.

the first absolute proof of the existence of highly organized animals living at depths of upwards of 1,000 fathoms."

In 1864 M. Sars, Swedish Government Inspector of Fisheries, while dredging off the Loffoten islands in a depth of 300 fathoms, brought up a variety of specimens of animals living at the bottom of the sea. Professor. Thomson visited Norway soon after, and had an opportunity of studying the specimens with M. Sars's father, the well-known Professor of Zoology in the University of Christiania. "Animal forms," Professor Thomson says in a letter to Dr. Carpenter, written for the information of the Royal Society, "were abundant; many of them were new to science. Among them was one of surpassing interest, the small Crinoid of which you have a specimen, and which we at once recognized as a degraded type of the Apiocrinidæ, an order hitherto regarded as extinct, which attained its maximum in the Pear-encrinites of the Jurassic period, and whose latest representative hitherto known was the Bourguetticrinus of the Chalk. Some years previously M. Absjornsen dredging in 200 fathoms in Hardangerfjiord procured several examples of a star-fish (Brisinga), which seems to find its nearest ally in the fossil genus Protaster. These observations place it beyond a doubt that animal life is abundant in the ocean at depths varying from 200 to 300 fathoms, that the forms of these great depths differ greatly from those met with in ordinary dredging, and that, at all events in some cases, these animals are closely allied to, and would seem to be directly descended from, the fauna of the Early Tertiaries.

"I

Before this letter was written, Dr. Carpenter, then one of the Vicepresidents of the Royal Society, had been spending some time in Belfast with Professor Thomson in the study of these Crinoids or Lily Stars. had long previously," says Thomson, "had a profound conviction that the land of promise for the naturalist, the only remaining region where there were endless novelties of extraordinary interest ready to the hand which had the means of gathering them, was the bottom of the deep sea. I had even had a glimpse of some of these treasures, for I had seen the year before, with Professor Sars, the forms dredged by his son at a depth of 300 or 400 fathoms off the Loffoten islands. I propounded my views to my fellow-labourer, and we discussed the subject many times over our microscopes. I strongly urged Dr. Carpenter to use his influence at headquarters to induce the Admiralty, probably through the Council of the Royal Society, to give us the use of a vessel properly fitted with dredging gear and all necessary scientific apparatus, that many heavy questions as to the state of things in the depths of the ocean, which were still in a state of uncertainty, might be definitely settled. Dr. Carpenter promised his hearty co-operation."

The Royal Society lost no time in applying to the Admiralty for the use of a gunboat, and the Lightning, under the command of Staff-Commander