“The Geology of the Voyage of the Beagle” 367 
preparing his Journal for publication. During the years 1837 to. 
1843, Darwin worked intermittently on the volumes of Zoology, all of 
which he edited, while he wrote introductions to those by Owen and 
Waterhouse and supplied notes to the others. 
Although Darwin says of his Journal that the preparation of the 
book “was not hard work, as my MS. Journal had been written with 
care.” Yet from the time that he settled at 36, Great Marlborough 
Street in March, 1837, to the following November he was occupied 
with this book. He tells us that the account of his scientific 
observations was added at this time. The work was not published 
till March, 1839, when it appeared as the third volume of the 
Narrative of the Surveying Voyages of H.M. Ships Adventure 
and Beagle between the years 1826 and 1836. The book was 
probably a long time in the press, for there are no less than 20 pages 
of addenda in small print. Even in this, its first form, the work 
is remarkable for its freshness and charm, and excited a great 
amount of attention and interest. In addition to matters treated 
of in greater detail in his other works, there are many geological 
notes of extreme value in this volume, such as his account of 
lightning tubes, of the organisms found in dust, and of the obsidian 
bombs of Australia. 
Having thus got out of hand a number of preliminary duties, 
Darwin was ready to set to work upon the three volumes which were 
designed by him to constitute The Geology of the Voyage of the Beagle. 
The first of these was to be on The Structure and Distribution of Coral- 
reefs. He commenced the writing of the book on October 5, 1838, 
and the last proof was corrected on May 6, 1842. Allowing for the 
frequent interruptions through illness, Darwin estimated that it cost 
him twenty months of hard work. 
Darwin has related how his theory of Coral-reefs was begun 
in a more “deductive spirit” than any of his other work, for in 
1834 or 1835 it “ was thought out on the west coast of South America, 
before I had seen a true coral-reef'.” The final chapter in Lyell’s 
second volume of the Principles was devoted to the subject of Coral- 
reefs, and a theory was suggested to account for the peculiar 
phenomena of “atolls.” Darwin at once saw the difficulty of accepting 
the view that the numerous and diverse atolls all represent submerged 
volcanic craters. His own work had for two years been devoted to 
the evidence of land movements over great areas in South America, 
and thus he was led to announce his theory of subsidence to account 
for barrier and encircling reefs as well as atolls. 
Fortunately, during his voyage across the Pacific and Indian 
Oceans, in his visit to Australia and his twelve days’ hard work at 
1L, Let. p. 70. 
