e Geological Society, an
office which he continued to hold for three years. And at each period of
enforced holiday, for his health had already begun to give way, he
occupied himself with geological work in the field. In the Midlands he
watched the operations of earthworms, and began those inquiries which
formed the subject of his last research, and of the volume on "Vegetable
Mould" which he published not long before his death. In the Highlands he
studied the famous Parallel Roads of Glen Roy; and his work there,
though in after-years he acknowledged it to be "a great failure," he
felt at the time to have been "one of the most difficult and instructive
tasks" he had ever undertaken.

In the beginning of 1839 Darwin married his cousin, daughter of Josiah
Wedgwood, and grand-daughter of the founder of the Etruria Works, and
took a house in London. But the entries of ill-health in his diary grow
more frequent. For a time he and his wife went into society, and took
their share of the scientific life and work of the metropolis. But he
was compelled gradually to withdraw from this kind of existence, which
suited neither of them, and eventually they determined to live in the
country. Accordingly, he purchased a house and grounds at Down, in a
sequestered part of Kent, some twenty miles from London, and moved
thither in the autumn of 1842. In that quiet home he passed the
remaining forty years of his life. It was there that his children were
born and grew up around him; that he carried on the researches and
worked out the generalizations that have changed the whole realm of
science; that he received his friends and the strangers who came from
every country to see him; and it was there that, after a long and
laborious life, full of ardor and work to the last, he died, at the age
of seventy-three, on April 19, 1882.

The story of his life at Down is almost wholly coincident with the
history of the development of his views on evolution, and the growth and
appearance of the successive volumes which he gave to the world. For the
first four years his geological tastes continued in the ascendant.
During that interval there appeared three remarkable works, his volume
on "Coral Islands," that on "Volcanic Islands," and his "Geological
Observations on South America."

After working up the geological results of the long voyage in the
Beagle, he set himself with great determination to more purely
geological details. While on the coast o