Mr H. Blackadder on Unusual Atmospherical Refraction. 69 
appearance of the coast of Fife was less changed by looming, 
but a very distinct inverted image was formed in the air, which 
did not take place with the coast of East Lothian. As the sun 
descended, the images became less distinct. The lighting up of 
the lighthouse on the Isle of May was now rather impatiently 
expected, and had it been lighted as soon as that on Inch Keith, 
an opportunity would have been afforded of witnessing a very 
beautiful spectacle, as the light might have been seen suspended 
both on the upright and inverted images at once. In this ex- 
pectation, however, we were disappointed. It may be here no- 
ticed, that, at ebb-tide, and in calm clear weather, the light of 
the Isle of May may be seen by the naked eye, at the level of 
the sea, to the westward of Leith ; when it appears like a small 
globe of fire resting on the sea at the horizon. 
On the evening succeeding these appearances, a considerable 
degree of cold took place on the grass, close by the sea-shore * ; 
and, in more inland situations, the grass was said to have been 
covered with hoar-frost. At S r. m., the temperature of the air 
was 45° ; that of the sea, and the soil of a garden near to it, were 
both 42°. In the course of the day, the barometer rose higher 
than it had been for at least the preceding week. In the early 
part of the day, as for some days previous, the wind was north- 
erly ; but, in the course of the night, an east wind wind sprang 
up, and continued to blow next day pretty strongly. 
The phenomena of the mirage may also be frequently wit- 
nessed in this neighbourhood, on a more contracted scale. Thus, 
two persons shall appear to be walking, where there is but one ; 
and the two objects shall, according to circumstances, advance 
and retire together, or move in opposite directions, similar to 
the mirage seen by M. Jurine on the lake of Geneva. A. 
tower shall appear as if cleft asunder, or a part of it to be cut 
off, and converted into the appearance of a sepulchral monu- 
ment ; and sometimes that of an altar burning with great inten- 
sity. The image of a man, dog, or other large object, shall 
be represented under his feet, as if walking on a mirror, and 
that of a smaller object inverted and suspended in the air. 
* In a walled-garden, a few yards from the shore, I have observed the temper- 
ature of the grass after sunset, 6° below that of the air, three feet from the ground, 
while in the open fields, the difference was comparatively trifling, — a fact of easy 
explanation, and meriting the attention of horticulturists. 
