Welcome
   Home | Texts by category | | Quick Search:   
Authors
Works by Aristotle
Pages of Meteorology



Previous | Next
                  

Meteorology   


are equal, the points where they form an angle will always lie on a

circle.

Let AGB and AZB and ADB be lines each of which goes from the point A

to the point B and forms an angle. Let the lines AG, AZ, AD be equal

and those at B, GB, ZB, DB equal too. (See diagram.)

Draw the line AEB. Then the triangles are equal; for their base

AEB is equal. Draw perpendiculars to AEB from the angles; GE from G,

ZE from Z, DE from D. Then these perpendiculars are equal, being in

equal triangles. And they are all in one plane, being all at right

angles to AEB and meeting at a single point E. So if you draw the line

it will be a circle and E its centre. Now B is the sun, A the eye, and

the circumference passing through the points GZD the cloud from

which the line of sight is reflected to the sun.

The mirrors must be thought of as contiguous: each of them is too

small to be visible, but their contiguity makes the whole made up of

them all to seem one. The bright band is the sun, which is seen as a

circle, appearing successively in each of the mirrors as a point

indivisible to sense. The band of cloud next to it is black, its

colour being intensified by contrast with the brightness of the

halo. The halo is formed rather near the earth because that is calmer:

for where there is wind it is clear that no halo can maintain its

position.

Haloes are commoner round the moon because the greater heat of the

sun dissolves the condensations of the air more rapidly.

Haloes are formed round stars for the same reasons, but they are not

prognostic in the same way because the condensation they imply is so

insignificant as to be barren.



4



We have already stated that the rainbow is a reflection: we have now

to explain what sort of reflection it is, to describe its various

Previous | Next
Site Search