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and more and less watery in different parts. Then the sight is

reflected to the sun: the mirrors are too small for the shape of the

sun to appear, but, the bright white light of the sun, to which the

sight is reflected, being seen on the uneven mirror, its colour

appears partly red, partly green or yellow. It makes no difference

whether sight passes through or is reflected from a medium of that

kind; the colour is the same in both cases; if it is red in the

first case it must be the same in the other.

Rods then are occasioned by the unevenness of the mirror-as

regards colour, not form. The mock sun, on the contrary, appears

when the air is very uniform, and of the same density throughout. This

is why it is white: the uniform character of the mirror gives the

reflection in it a single colour, while the fact that the sight is

reflected in a body and is thrown on the sun all together by the mist,

which is dense and watery though not yet quite water, causes the sun's

true colour to appear just as it does when the reflection is from

the dense, smooth surface of copper. So the sun's colour being

white, the mock sun is white too. This, too, is the reason why the

mock sun is a surer sign of rain than the rods; it indicates, more

than they do, that the air is ripe for the production of water.

Further a mock sun to the south is a surer sign of rain than one to

the north, for the air in the south is readier to turn into water than

that in the north.

Mock suns and rods are found, as we stated, about sunset and

sunrise, not above the sun nor below it, but beside it. They are not

found very close to the sun, nor very far from it, for the sun

dissolves the cloud if it is near, but if it is far off the reflection

cannot take place, since sight weakens when it is reflected from a

small mirror to a very distant object. (This is why a halo is never

found opposite to the sun.) If the cloud is above the sun and close to

it the sun will dissolve it; if it is above the sun but at a

distance the sight is too weak for the reflection to take place, and

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