Ready reckoner with cursor Ready reckoner with cursor, plastic, for temperature-pressure relation of ICI refrigerants. Materials: plastic (unidentified) Object Number: 1988-308/1 type: ready reckoner Image © The Board of Trustees of the Science Museum
Plastic case for ready reckoner Plastic case printed "Unitor Ships Service. Refrigerant Slide Rule", for ready reckoner with cursor. Materials: plastic (unidentified) Object Number: 1988-308/2 type: case Image © The Board of Trustees of the Science Museum
SCM Marchant electromechanical calculating machine, model VTR, serial no. 673579 SCM Marchant electromechanical calculating machine
Comptometer by Felt & Tarrant Manufacturing Co., USA, c. 1920 Comptometer by Felt & Tarrant Manufacturing Co.
Flying Fish manual calculating machine, model JSY-20, Serial no. 648635 by the Shanghai Calculating & Typewriter MFG Works, c. 1965 Flying Fish manual calculating machine
Three sets of prototype cards for the 13, 14 and 17 times tables Three sets of prototype cards for the 13
