THE following pages consist mainly of an account of an expedition to the volcanic island of Krakatau which I had an opportunity of making in the spring of 1906 in company with some other botanists. The work was originally published in the Vierteljahrsschrift der naturforschenden Gesellschaft in Zürich (Jahrgang 52, 1907): a few reprints only were available for purchase. I therefore agreed with pleasure to the proposal made to me by the Cambridge University Press to publish an English translation, particularly as Professor Seward, who carried out the preliminary negotiations, kindly offered to be the translator. I wish to express my cordial thanks to him. I would also thank the Syndics of the University Press for the care with which the volume has been produced.

Four hitherto unpublished photographs have been added to those published in the German edition. I have also taken the opportunity of making a few corrections and additions, so that the English translation may be regarded as a second edition of the original work.