Page "Burning glass" Paragraph 8

Chapter 17 of William Bates ' 1920 book Perfect Sight Without Glasses, in which the author argues that observation of the sun is beneficial to those with poor vision, includes a figure of somebody " Focussing the Rays of the Sun Upon the Eye of a Patient by Means of a Burning Glass.

" Needless to say, this is highly dangerous and will damage the eye in seconds.