"I remarked constantly, just at sunset, in these latitudes, that the eastern horizon was brilliantly illuminated with a kind of mock sunset. This in a short time disappeared, to be soon succeeded by another similar in character, but more faint"

George Grey's quote is describing a phenomenon that he observed in the latitudes he was in. He noticed that at sunset, the eastern horizon was illuminated with a fantastic light that resembled a sunset. This light would quickly disappear and be changed by a comparable, but fainter light. This phenomenon is likely caused by the reflection of the sun's light off of the clouds in the sky. The clouds function as a mirror, reflecting the light and producing a mock sunset. This phenomenon is likely more noticeable in certain latitudes due to the angle of the sun's light and the clouds in the sky. George Grey's quote is a testament to the appeal of nature and the wonders that can be seen in the sky.