In 1840 a Polish nobleman named Strzelecki, who had been travelling among the ranges round Mount Kosciusko, stated that, from indications he had observed, he was firmly persuaded of the existence of gold in these mountains; but the Governor asked him, as a favour, to make no mention of a theory which might, perhaps, unsettle the colony, and fill the easily excited convicts with hopes which, he feared, would prove delusive. Strzelecki agreed not to publish his belief; but there was another man of science who was not so easily to be silenced. The Rev. W. B. Clarke, a clergyman devoted to geology, exhibited specimens in Sydney, on which he based an opinion that the Blue Mountains would, eventually, be found to possess goldfields of great extent and value. Some of these were taken to London by Strzelecki; and in 1844 a great English scientist, Sir Roderick Murchison, read a paper before the Royal Geographical Society in which he expressed a theory similar to that of Mr. Clarke. In 1846 he again called attention to this subject, and showed that, from the great similarity which existed between the rocks of the Blue Mountains and those of the Urals, there was every probability that the one would be found as rich as the other was known to be in the precious metals. So far as theory could go, the matter had been well discussed before the year 1851, but no one had ventured to spend his time and money in making a practical effort to settle the question. [Illustration: EDWARD HARGRAVES.]