Ready Reckoners

Figure 1 Webster Front Page 1634 ..................................................................................................................... 2 Figure 2 Webster's 1634 Compound Interest Table............................................................................................ 2 Figure 3 Frontispiece of Barreme, 1762 ............................................................................................................. 2 Figure 4 Non-Decimal measures ........................................................................................................................ 3 Figure 5 Dates of decimalisation or metrication ................................................................................................. 3 Figure 6 Schematic part of a steel warehouse invoice with eight multiplications .............................................. 4 Figure 7 Comparison of adding versus multiplication time................................................................................ 5 Figure 8 Characteristics of different classes of aids ........................................................................................... 6 Figure 9 Estimated Sales Volumes by Aid Class................................................................................................ 6 Figure 10 Title Page from first American Ready Reckoner 1774 ...................................................................... 8 Figure 11 Page from Leybourne 1798 ................................................................................................................ 9 Figure 12 Triangular Multiplication Table from The Express Ready Reckoner by Gall & Inglis. .................... 9 Figure 13 Dunlop’s calculator GB Patent 124/1862 Abridgment...................................................................... 9 Figure 14 Anlezark’s entirely new System 1871................................................................................................ 9 Figure 15 Universal Schnellrechner ................................................................................................................... 9 Figure 16 Multiplication Table from Bergmann Universal Calculator with The Correntator Stylus adder, 1920 ................................................................................................................................................................. 10 Figure 17 Three erratum slips probably due to printer’s error ....................................................................... 11 Figure 18 World Sales by Decade from 1749................................................................................................... 13 Figure 19 World Items per Decade and Cumulative......................................................................................... 14 Figure 20 Items by Calculation type................................................................................................................. 14 Figure 21 Items in 16 User classes ................................................................................................................... 14 Figure 22 Output of GB and US Publishers in order of number ...................................................................... 14