14 Observations on a Mirage. 



three or four feet across, of loose soil, freed from all roots of 

 scrub or grass, — the history and use of which are at present 

 unknown to me. Although a very shy bird naturally, at- 

 tempts to domesticate it by rearing the young under a common 

 fowl have succeeded sufficiently to induce further efforts, 

 with greater care for the safe custody of the chicks. 



A nest of the Lyre-tailed Pheasant will be forwarded to 

 the Museum when an opportunity occurs for its transmission, 

 by land or sea, from this presently inaccessible locality. 



Art. III. — On the Phenomena attending an Interesting Case 

 of Mirage. By Professor Wilson, M.A., Melbourne 

 University. 



[Communicated to the Institute 4th February, 1857.] 



On Sunday, 18th January last, about a quarter before two 

 o'clock, I observed an interesting case of Mirage on the 

 Sydney road. I was standing about twenty yards from the 

 south-east entrance to the Royal Park, looking towards 

 Brunswick. The road here is three chains wide, very dusty, 

 bounded on the left by the trees of the Royal Park, and on 

 the right by those of the Prince's Park ; at the farther end, 

 distant about a mile and a quarter, the " Sarah Sands Hotel," 

 is visible and some trees with a well-marked outline. On 

 the day in question the house and trees appeared to rise out 

 of a lake, brilliantly illuminated by the sun, and in parts 

 slightly agitated by the wind, but not so as to interfere with 

 a very distinct inverted image of the house and trees formed 

 by reflexion in the seeming water. 



My position was at the foot of a slight rise in the road, 

 the summit of which, at the distance of a few yards, was 

 nearly on a level with the eye. The sandy surface of the 

 ground was much heated by the sun, and at the same time a 

 cool south wind was blowing briskly, so that the ah-, heated 

 and rarified by contact with the ground, was rapidly cleared 

 off by the cool wind, leaving only a thin film of rarified air 

 along the surface of the ground. The rays of light from the 

 sky, and objects at a distance of more than a mile incident 

 on the surface of this rarer medium at nearly a right angle, 

 suffered reflexion in a manner very analogous to that known 

 as total internal reflexion, and thus produced the inverted 



