Optical Formulae compiled by H.P. Wilkins.

A red-bound notebook of technical formulae, calculations, drawings and other information relating to the optical work and inventions of H. P. Wilkins.

The first page is stamped SECRET in red ink, and reads: "OPTICAL FORMULAE/Compiled by/ H. Percy Wilkins, F.R.A.S./ Maker of Reflecting Telescopes, Spectroscopes etc./ Author of the World's greatest Moon Map./ Member of the British Astronomical Association." His address is recorded as Bornehurst, Kent, and the date is given as 1938.

The notebook contents are written as fair copies, and an index is included. One photograph is pasted into the book, showing a child posing with a 6 1/2-inch reflecting telescope.