Thursday, 21st August, Rocky Gorge, River Strangways. At 7.30 despatched Thring and King to see if there is any water in the Ponds. Resting horses, repairing saddle-bags, etc. Day hot, night and morning cool; wind, south-east. My sight has been very much impaired during the last month; after sundown, I am in total darkness. Even though the moon is full, and shining bright and clear to the others, to me it is darkness; I can see her dimly, but she gives me no more light than if she had been painted on a piece of canvas. I am now quite incapable of taking observations at night, and I am most thankful this did not happen before I was enabled to reach the ocean, as the most of my observations are taken at night. After the equinox the sun is too high to be measured by the sextant in the artificial horizon.