Yves Le Grand and the dioptric power matrix

Abstract

In a previously published paper, the present author asserted that Yves Le Grand came veryclose to describing the dioptric power matrix in 1945 and that, in particular, he presentedexpressions for the entries of the matrix. The purpose of this note is to weaken that assertionand to argue that, while he certainly did describe some features of the matrix, his expression forthe off-diagonal entries of the matrix for thin systems was incorrect (a missing factor appearsnot to have been a typographical error) and that, although he gave basic formulae of Gaussianoptics involving dioptric power, he gave no hint of natural and powerful generalisations forlinear optics involving the dioptric power matrix.