Ix THE DEBT OF SCIENCE TO DARWIN 455 
were found to exhibit a progressive advancement from 
ancient to recent times, while the breaks in the series 
between each great geological formation were held to show 
that the older forms of life had been destroyed, and were 
replaced by a new creation of a more advanced organisation 
suited to the altered conditions of the world. 
And thus, perhaps, we might have gone on to this day, 
ever accumulating fresh masses of fact, while each set of 
workers became ever more and more occupied in their own 
departments of study, and, for want of any intelligible theory 
to connect and harmonise the whole, less and less able to 
appreciate the labours of their colleagues, had not Charles 
Darwin made his memorable voyage round the world, and 
thenceforth devoted himself, as so many had done before him, 
to a life of patient research in the domain of organic nature. 
But how different was the object attained! Others have 
added greatly to our knowledge of details, or created a 
reputation by some important work; he has given us new 
conceptions of the world of life, and a theory which is itself 
a powerful instrument of research; has shown us how to 
combine into one consistent whole the facts accumulated 
by all the separate classes of workers, and has thereby 
revolutionised the whole study of nature. Let us endeavour 
to see by what means he arrived at this vast result. 
The Voyage of the BEAGLE 
Passing by the ancestry and early life of Darwin, which 
have been made known to the whole reading public by many 
biographical notices and recently by the publication of his 
Life and Letters, we may begin with the first event to which 
we can distinctly trace his future greatness—his appointment 
as naturalist to the Beagle, on the recommendation of his 
friend and natural-history teacher, Professor Henslow, of 
Cambridge University. It was in 1831, when Darwin, then 
twenty-two years of age, had just taken his B.A. degree, that 
he left England on his five years’ voyage in the Southern 
Hemisphere. It is probably to this circumstance that the 
world owes the great revolution in our conception of the 
organic world so well known as the Darwinian theory. The 
opportunity of studying nature in new and strange lands ; 
