With respect to the second point, or the reasons which have led to this work being published at all, the author would observe that he has been led to engage in it rather from a sense of duty, and at the instance of many of his friends, than from any wish of his own. The greater portion of the country he explored was of so sterile and worthless a description, and the circumstances which an attempt to cross such a desert region led to, were of so distressing a character, that he would not willingly have revived associations, so unsatisfactory and so painful. It has been his fate, however, to cross, during the course of his explorations, a far greater extent of country than any Australian traveller had ever done previously, and as a very large portion of this had never before been trodden by the foot of civilized man, and from its nature is never likely to be so invaded again, it became a duty to record the knowledge which was thus obtained, for the information of future travellers and as a guide to the scientific world in their inquiries into the character and formation of so singular and interesting a country. To enable the reader to judge of the author's capabilities for the task he undertook, and of the degree of confidence that may be due to his impressions or opinions, it may not be out of place to state, that the Expeditions of 1840--1 were not entered upon without a sufficient previous and practical experience in exploring. For eight years the author had been resident in Australia, during which he had visited many of the located parts of New South Wales, Port Phillip, South Australia, Western Australia, and Van Diemen's Land. In the years 1836, 1837, 1838, 1839, and 1840 he had conducted expeditions across from Liverpool Plains in New South Wales to the county of Murray, from Sydney to Port Phillip, from Port Phillip to Adelaide, and from King George's Sound to Swan River, besides undertaking several explorations towards the interior, both from Port Lincoln and from Adelaide. To the knowledge and experience which were thus acquired, the author must ascribe the confidence and good opinion of his fellow-colonists, which led them in 1840 to place under his command an undertaking of such importance, interest, and responsibility; and to these advantages he feels that he is in a great measure indebted, under God's blessing, for having been enabled successfully to struggle through the difficulties and dangers which beset him, in crossing from Adelaide to King George's Sound.