MIRAGES—GORDON oan 
purpose. Stockmen tell me that a mirage may fool men and ducks but 
never stock. It just does not smell like water, and cattle refuse to be 
interested, even if very thirsty. 
A rather infrequent activity of the No. 1 lens is far removed from 
making water seem to be where there is none. In its role of making an 
object seem to be lower than it is, it sometimes makes a mountain range 
low on the horizon seem to drop out of sight. Since the range is, with 
the effect of distance, already very little above lens level, light from it 
would have difficulty entering the top of the lens unless it should be 
on a slope dropping away from the observer. In that case, the ight 
path could be turned up to pass over the head of the observer, or if 
there were no slope, light could enter the far side of the lens and be 
turned up with the same result. 
Is it possible that this might be in conflict with the celestial mirage 
effect which makes sun and moon and stars seem to be higher above 
the horizon than they are, if the sun, for instance, were setting behind 
that particular range? 
Mention has been made of the three widely different activities of the 
No. 2 lens. Names in the modern manner have been chosen to identify 
these activities: Operation Liftup, Operation Distortion, and Opera- 
tion Long Distance. 
Normally, temperature and density of the air decrease steadily with 
elevation. Under such conditions neither No. 1 nor No. 2 lenses could 
be formed. As we have seen, a superheated ground surface raising the 
temperature of the air immediately above it reverses the density trend 
and we got a No. 1 lens. Over a cold ground surface, and frequently 
aloft in the atmosphere, the temperature trend is reversed, stepping up 
the rate of density decrease. Sometimes, and in certain locations, this 
abnormally steep density gradient will result in the formation of a 
mirage-forming air lens. 
OPERATION LIFTUP 
For Operation Liftup, such a lens may be formed over the cold 
ground surface of a ridge about midway between, and higher than, 
the object and the observer. Based on the ground, it will be, in effect, 
saddled over the ridge, and light can not reach it from below, as 
shown in the diagram. Apparently instead, light enters the object 
side of the lens, follows its curve over the ridge, and escapes the 
opposite side to pass down the slope to the observer. This lens can 
pick up the image of a house or a town or a mountain range hidden 
behind the ridge and lift it into sight. Within my experience and 
judged from evidence from the many stories I have heard, it invariably 
turns out a clear, sharp picture, without distortion. A friend told me 
of seeing, as a boy, a neighbor’s house over the ridge lifted into sight so 
clearly that he could recognize the children playing about. In the 
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