Ready reckoner
1990
Ready reckoner (weights and measures)
1972-1976
Arithmetical medal and numerical pocket piece
1753
"The Readiest Reckoner in miniature"
1824
Scherer's "Logarithmischgraphische Rechentafel"
1880-1892
The "Proell" pocket calculator
Equation of Time Calculator, French, 1816
1816-1821
Battenburg's speed and distance scale by Elliott Bros.
The 'Tachypoly Plasiasme' ready reckoner, 1880-1884
1880-1884
"McFarlane's Calculating Cylinder" (c. 1833)
1833
Gripalculator slide rule patent no.335379 of 1929
Aristo 10076 chemist conversion ready reckoning rule for temperature
1970-1975
Hines' 'Patent Weight and Quantity Calculator', c.1908.
circa 1908
Ready reckoner (musical)
1785-1790
Klinkerfues ready reckoner calculator for psychrometers, 1870-1876
1870-1876
The 'Multiplicateur Enfantin' ready reckoner, c 1880.
1876-1884
Aristo 10075E dyers ready reckoning conversion rule for temperature
1970-1975
Aristo 10075 dyers ready reckoning conversion rule for temperature
1970-1975
Robertson's 'Rapid Calculator', c 1910.
1910-1920
The 'Tachylemme' ready reckoner, c 1876.
circa 1876
C.D. Indicator
Bate's ready reckoner
1824
White & Bean's area scale on transparent celluloid
1907
Parker's Prestometer Tablet, mid 19th century
circa 1860
"The Banker's Sure Guide or Monied Man's Assistant"
1791
"The Model Ready Reckoner"
1867
"Toutechnique" protractor-calculator
Cullum's Calculator
Selection of four ready reckoners
1972-1976
McFarlane's calculating cylinder
Unit conversion slide rule and metric unit converter in slide-rule format
1975
Three card slide rule ready reckoners by Omaro
1935-1939