were many different stones; but its perpendicular cliffs were of a dark bluish grey colour, shining when broken, very heavy, and close grained. Mount Harris, and Mount Exmouth, are composed of distinct materials, and in their formation bear not the slightest resemblance to each other; the granite of the former being more allied to the hills to the south-south-east of it, from which however it is distant at least one hundred miles, a perfect level filling up the intermediate space. Many new, and otherwise interesting subjects of the indigenous botany were discovered on the hills: among which were a species of persoonia, not previously observed, some xanthorrhaeae or grass trees, and two or three coast plants. The heteromorphous sterculia of the interior, and some species of eucalyptus of very stunted growth covered its sides, which however for a considerable distance were not deficient in grass. Sandstone was found in large masses in the rivulet at its base, with pebbles of various colours, and of species none of which was found on the mount itself. It was near four o'clock before we returned to the tent, highly gratified with our excursion. August 9.--In the course of the day, I again ascended Loadstone Hill, and repeated the experiments made on Friday, with the same results. Several different stations on the summit were tried, and the needle was variously affected; the spot where the phenomenon was first observed seemed to have the greatest effect on the needle. A common sewing needle was strongly rubbed with a magnet, and balanced on the point of the rock, when it was much agitated, and the point flew round from the north to the south. The needle of the circumferenter, taken out of the box, was affected in a similar manner, only that when balanced on the rock, the fluid did not possess sufficient power to turn the point more than one point of the circle instead of quite round, as when balanced in the compass box. A compound magnet was laid on the rock, and applied to it in different ways, but it did not seem in any manner affected by the power which had so surprised us with its effect on the compass. The weather within the last week has become perceptibly warmer: the thermometer being seldom under 70 degrees at noon. The fires of the natives were seen at no great distance from us; and they seem to attend upon our motions pretty closely. The observations made here placed us in lat. 31. 13. S., long. 148. 41. 30. E., and I estimate the mean variation to be about 7 1/2 easterly. We found that no reliance could be placed on bearings taken with the compass on heights in this vicinity, and I am fearful that the bearings taken from Mount Exmouth will require verification, a difference of 4 degrees being observed in some, when compared with other bearings, which could not be supposed to be affected by the magnetic fluid.