ly streams from our bodies? These images when they strike
anything smooth and solid are reflected by the shock and reversed in
such wise as to give back an image turned to face its original. Or
should we accept the view maintained by other philosophers that rays
are emitted from our body? According to Plato these rays are filtered
forth from the centre of our eyes and mingle and blend with the light
of the world without us; according to Archytas they issue forth from
us without any external support; according to the Stoics these rays
are called into action[8] by the tension of the air: all agree that,
when these emanations strike any dense, smooth, and shining surface,
they return to the surface from which they proceeded in such manner
that the angle of incidence is equal to the angle of reflection, and
as a result that which they approach and touch without the mirror is
imaged within the mirror.

[Footnote 8: _facti_ MSS.]

16. What think you? Should not philosophers make all these problems
subjects of research and inquiry and in solitary study look into
mirrors of every kind, solid and liquid? There is also over and above
these questions further matter for discussion. For instance, why is
it that in flat mirrors all images and objects reflected are shown in
almost precisely their original dimensions, whereas in convex and
spherical mirrors everything is seen smaller, in concave mirrors on
the other hand larger than nature? Why again and under what
circumstances are left and right reversed? When does one and the same
mirror seem now to withdraw the image into its depths, now to extrude
it forth to view? Why do concave mirrors when held at right angles to
the rays of the sun kindle tinder set opposite them? What is the cause
of the prismatic colours of the rainbow, or of the appearance in
heaven of two rival images of the sun, with sundry other phenomena
treated in a monumental volume by Archimedes of Syracuse, a man who
showed extraordinary and unique subtlety in all branches of geometry,
but was perhaps particularly remarkable for his frequent and attentive
inspection of mirrors. If you had only read this book, Aemilianus,
and, instead of devoting yourself to the study of your fields and
their dull clods, had studied the mathematician's slate and
blackboard, believe me, although your face is hideous enough for a
tragic mask of Thyestes, you would assuredly, in your desire for the
acquisition of knowledge, look into