XVI.
Solution.
Joannetti remained in the attitude I have described, awaiting the explanation he had asked of me. I withdrew my head from the folds of my travelling dress, into which I had thrust it that I might meditate more at my ease; and after a moment's silence, to enable me to collect my thoughts after the reflections I had just made, I said, turning my arm-chair toward him,—
"Do you not see that as a picture is a plane surface, the rays of light proceeding from each point on that surface....?"
At that explanation, Joannetti stretched
