138 THE OCEAN. 
Lawrence. Sometimes another image may be seen 
abavethe inverted one, and sometimes, but very rarely, 
even a fourth. In such cases, the third is always 
‘in a right position, and the fourth inverted like 
Distortions oF IrREGULAR REFRACTION. 
the second. An image of a vessel is sometimes seen 
projected upon the sky, when nothing corresponding 
to it is visible below, the real object being far below 
the horizon. Mr. Scoresby. thus saw his father’s 
ship, the Fame, drawn upon the sky, and by the aid 
of a telescope could make her out so distinctly as to 
pronounce with confidence upon her identity, when, 
by comparing notes afterwards, it was found that she 
was thirty miles distant at the time, and seventeen 
miles from the extreme point of vision. Somewhat 
allied to this is the bright gleam seen by night above 
field-ice, called 2ce-blink, which is often very service- 
