The care with which I had noted every change that took place in the Macquarie, from Wellington Valley downwards, enabled me, in some measure, to account for its present features. I was led to conclude that the waters of the river being so small in body, excepting in times of flood, and flowing for so many miles through a level country without receiving any tributary to support their first impulse, became too sluggish, long ere they reached the marshes, to cleave through so formidable a barrier; and consequently spread over the surrounding country--whether again to take up the character of a river, we had still to determine. Unless, however, a decline of country should favour its assuming its original shape, it was evident that the Macquarie would not be found to exist beyond this marsh, of the nature and extent of which we were still ignorant. The loss of my barometer was at this time severely felt by me, since I could only guess at our probable height above the ocean; and I found that my only course was to endeavour to force my way to the northward, to ascertain, if I could, from the bottom of the marshes; then penetrate in a westerly direction beyond them, in order to commence my survey of the S.W. interior. I was aware of Mr. Hume's perseverance, and determined, therefore, to wait the result of his report ere I again moved the camp, to which we returned late in the afternoon of the second day of our departure. We found it unsufferably hot and suffocating in the reeds, and were tormented by myriads of mosquitoes, but the waters were perfectly sweet to the taste, nor did the slightest smell, as of stagnation, proceed from them. I may add that the birds, whose sanctuary we had invaded, as the bittern and various tribes of the galinule, together with the frogs, made incessant noises around us, There were, however, but few water-fowl on the river; which was an additional proof to me that we were not near any very extensive lake. MR. HUME'S REPORT. Mr. Hume had returned before me to the camp, and had succeeded in finding a serpentine sheet of water, about twelve miles to the northward; which he did not doubt to be the channel of the river. He had pushed on after this success, in the hope of gaining a further knowledge of the country; but another still more extensive marsh checked him, and obliged him to retrace his steps. He was no less surprised at the account I gave of the termination of the river, than I was at its so speedily re-forming, and it was determined to lose no time in the further examination of so singular a region. FALSE CHANNEL; PERPLEXITIES.