Dual action keyboard 169 Non-add signal 170 Selective split keyboard 170 Selective printing cut-out 171 Grand totalizer 171 Alternate cross printing 171 Determinate item signal 172 Subtraction by reverse action 172 Selective split for keyboard 172 Rapid paper insert and ejector 172 THE BOOKKEEPING AND BILLING MACHINE Early combinations 174 First practical combination 177 Moon-Hopkins Billing machine 177 Napier’s Bones first direct multiplier 181 First direct multiplying machine 181 Description of Barbour Multiplier 182 Description of Bollee machine 188 Bollee’s principle commercialized 189 A CLOSING WORD