of Darwin. No one can be more deeply moved by a sense of this gratitude than was Mr. Darwin himself. His letters, written to Prof. Henslow during his voyage round the world, overflow with feelings of affection, veneration, and obligation to his accomplished master and dearest friend-feelings which throughout his life he retained with undiminished intensity. As he used himself to say, before he knew Prof. Henslow, the only objects of natural history for which he cared were foxes and partridges. But owing to the impulse which he derived from the field excursions of the Henslow class, he became while at Cambridge an ardent collector, especially in the region of entomology; and we remember having heard him observe that the first time he ever saw his own name in print was in connection with the capture of an insect in the fens.

During one of these excursions Prof. Henslow told him that he had been commissioned (through Prof. Peacock) to offer any competent young naturalist the opportunity of accompanying Captain Fitzroy as a guest on the surveying voyage of the Beagle, and that he would strongly urge its acceptance

on him. Mr. Darwin had already formed a desire to travel, having been stimulated thereto by reading Humboldt's Personal Narrative; so after a short hesitation on the part of his father, who feared that the voyage might "unsettle" him for the Church, the matter was soon decided, and in December of 1838 the expedition started. During the voyage he suffered greatly from sea-sickness, which, together with the fasting and fatigue incidental to long excursions over-land, was probably instrumental in producing the dyspepsia to which, during the remainder of his life, he was a victim. Three years after returning from this voyage of circumnavigation, he married, and in 1842 settled at Down, in Kent. The work which afterwards emanated from that quiet and happy English home, which continued up to the day of his death, and which has been more effectual than any other in making the nineteenth century illustrious, will form the subject of our subsequent articles.

G. J. R.

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II.

WORK IN GEOLOGY.

No man of his time has exercised upon the science of Geology a profounder influence than Charles Darwin. At an early period of his life he took much interest in geological studies, and in later years, while engaged in other pursuits, he kept himself acquainted with the progress that was being made in this department of natural knowledge. His influence upon it has been twofold, arising partly from the importance and originality of some of his own contributions to the literature of the science, but chiefly from the bearing of his work on other branches of natural history.

When he began to direct his attention to geological inquiry the sway of the Cataclysmal school of geology was still paramount. But already the Uniformitarians were gathering strength, and,

before many years were past, had ranged themselves under the banner of their great champion, Lyell. Darwin, who always recognised his indebtedness to Lyell's teaching, gave a powerful impulse to its general reception by the way in which he gathered from all parts of the world facts in its support. He continually sought in the phenomena of the present time the explanation of those of the past. Yet he was all the while laying the foundation on which the later or Evolutional school of geology has been built up.

But

Darwin's specially geological memoirs are not numerous, nor have they been of the same epochmaking kind as his biological researches. every one of them bears the stamp of his marvellous acuteness in observation, his sagacity in grouping scattered facts, and his unrivalled far-reaching vision that commanded all their mutual bearings, as well as their place in the general economy of things. His long travels in the Beagle afforded him opportunities of making himself acquainted with geological phenomena of the most varied kinds. With the exception of one or two minor papers written in later years, it may be said that

all his direct contributions to geology arose out of the Beagle voyage. The largest and most important part of his geological work dealt with the hypogene forces of nature-those that are concerned in volcanoes and earthquakes, in the elevation of mountains and continents, in the subsidence of vast areas of the sea-bottom, and in the crumpling, foliation, and cleavage of the rocks. of the earth's crust. His researches in these subjects were mainly embodied in the Geology of the Voyage of the Beagle-a work which, in three successive parts, was published under the auspices of the Lords of the Treasury.

The order chosen by Darwin for the subjects of these three parts probably indicates the relative importance with which they were regarded by himself. The first was entitled The Structure and Distribution of Coral Reefs (1842). This well-known treatise, the most original of all its author's geological memoirs, has become one of the recognised classics of geological literature. The origin of those remarkable rings of coral-rock in mid-ocean had given rise to much speculation, but no satisfactory solution of the problem had been proposed. After

C