Laboratory Notes by Professor Tait - 3. On a simple Mode of explaining the Optical Effects of Mirrors and Lenses

1872 Proceedings of the Royal Society of Edinburgh  
It is very singular to notice how small a matter makes the difference between the intelligibility and unintelligibility of a demonstration to an audience as a whole not mathematical. In no part of Physics have I found this so marked as in the most elementary portions of geometrical optics. Such a formula aswhen interpreted directly as signifying that "the sum of the reciprocals of the distances of the object and image from the surface of a concave spherical mirror, is equal to double the
more » ... o double the reciprocal of the radius of the mirror,". if understood at all, is understood as a sort ofmemoria technicawhich enables the student to make calculations; but unless he have some knowledge of mathematics it suggests absolutely no higher meaning.
doi:10.1017/s0370164600042334 fatcat:5dcv3itjyrcndfhprkulyvv5am