...
Chinese Abacus
Div  

 

...
Keuffel & Esser Desk Slide Rule, No. N4096, c. 1930
Div  

 

J.R. Dempster RotaRule Pocket Slide Rule, No. AA., after 1933
Div  

 

Keuffel & Esser Polyphase Duplex Decitrig Slide Rule, Model 40713, c.1939
Div  

 

Keuffel & Esser Log Log Duplex Decitrig Slide Rule 40813, c. 1955
Div  

 

Eugene Dietzgen Co. “National" Maniphase Slide Rule, No. 1767, c. 1958
Div  

 

Pickett & Eckel Inc. Power Log Exponential Slide Rule, Model N 3ES, c.1960
Div  

 

...
Otis King’s Pocket Calculator, Scale No. 423, c. 1922Keuffel & Esser Thacher’s (Cylindrical) Calculating Instrument, c. 1927
Div  

 

Keuffel & Esser Thacher’s (Cylindrical) Calculating Instrument, c. 1927
Div  

 

Curta Co Cylindrical (Mechanical) Calculating Machine Type 1, c. 1948
Div  

 
