Selenium exposure meters, calculators and tables, including Weston Universal, Leica meter, Master II, III, III Ciné, IV, V, Avo, General Electric, Bertram, Gossen; Rotary-type calculators including a Lumiere Autochrome calculator, Agfa, Ilford, Ensign, Johnson and Wellcome; Slide-Rule calculators including Dibdins Automatic Exposure meter; Exposure tables including Imperial meters; and related historical literature.(a lot).