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