Early in 1869, Dr. Von Mueller, of the Melbourne Botanic Gardens, a botanist of high attainments, proposed to the Government of Western Australia that an expedition should be undertaken from the colony for the purpose of ascertaining, if possible, the fate of the lost explorer, Leichardt. Reports had reached Perth of natives met with in the eastern districts, who had stated that, about twenty years before (a date corresponding with that of the last authentic intelligence received from Leichardt), a party of white men had been murdered. This tale was repeated, but perhaps would not have made much impression if a gentleman, Mr. J.H. Monger, when on a trip eastward in search of sheep-runs, had not been told by his native guide that he had been to the very spot where the murder was committed, and had seen the remains of the white men. His story was very circumstantial; he described the spot, which, he said, was near a large lake, so large that it looked like the sea, and that the white men were attacked and killed while making a damper--bread made of flour mixed with water, and cooked on hot ashes. So certain was he as to the exact locality, that he offered to conduct a party to the place. This appeared like a trustworthy confirmation of the reports which had reached the colony, and created a great impression, so that the Government felt it a duty incumbent on them to make an effort to ascertain the truth of this statement, and Dr. Von Mueller's offer to lead an expedition was accepted. I was then, as now, an officer of the Survey Department, and employed in a distant part of the colony. I was ordered to repair to headquarters, to confer with the authorities on the subject, and was offered the appointment of second in command and navigator. This was a proposition quite in accordance with my tastes, for I had long felt a deep interest in the subject of Australian exploration, and ardently desired to take my share in the work. I at once arranged the equipment of the expedition, but, while so engaged, the mail from Melbourne brought a letter from Dr. Von Mueller, to the effect that his other engagements would not permit him to take the lead as proposed, and I was appointed to take his place in the expedition. OFFICIAL INSTRUCTIONS. The Honourable Captain Roe, R.N., the Surveyor-General, who had himself been a great explorer, undertook the preparation of a set of Instructions for my guidance; and they so accurately describe the objects of the journey, and the best modes of carrying them out, that I transcribe the official letter:-- Survey Office, Perth, 13th April, 1869. Sir,