Papers on Reverse Notation and the Perfect Rectangle Papers relating largely to reverse notation, comprising: table of contracted symbols for two digits together in scale of six notation; division using reverse notation; reverse notation in binomial coefficients and factorials; reverse notation in month and year numbers reverse notation in logarithms to base six and base twelve in six scale, and conversion factors table for conversion of duodecimals to scale of six magic square in reverse notation positive and negative numbers to scale of two, showing addition and multiplication; note entitled "Perfect Rectangle Ideas"; question relating to plane directed networks notes entitled "Perfect Rectangle Theory"; notes entitled "Theory of F-Matrices"; notes entitled "On Certain Self-Dual Networks". c1940s