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The USA was the closest rival to Germany for the variety of slide adders made. However it was unsurpassed in the field of dial adders in the twentieth century. Eventually its calculator industry succumbed to Japanese imports (such as the Magic Brain) before mechanical calculators disappeared under the onslaught of electronics.
The Lightning
Lightning Adding Machine Co, Los Angeles, California
7 dials, 7 digit display
Steel
12 x 2.5 inches
Circa 1950
Obtained from the USA
Sterling Dial-a-Matic adding machine, desk model, No. 567
Sterling Plastics Co, Mountainside, NJ
5 dials, 5 digit display; no reset facility
Plastic; 9.3 x 3 inches
1950s/1960s (Patented in UK & USA in 1957)
With plastic stylus and card box
Obtained from the USA
They were made in 4, 5 and 6 digit versions, sometimes combined with a pencil box.
Tasco Pocket Arithmometer
8 slides, 8 digit display
Sliding front panel for subtraction
Plated steel
5.5 x 3 inches
With leathercloth case and stylus
Circa 1950s
Obtained from the USA
Based on the German “Trick”
Back to top.
Kalkometer
8 slides, 8 digit display
Metal and plastic
5.5 x 3.3 inches
With PVC case, stylus and instructions
Circa 1960s
Made in USA
Obtained from the USA
Sterling Dial-a-Matic adding machine, No. 565
Sterling Plastics Co, Mountainside, NJ
4 dials, 4 digit display; no reset facility
Plastic; 8 x 2.3 inches
1950s/1960s (Patented in UK & USA in 1957)
With plastic stylus and card box
Obtained from the USA
“Tom Thumb Adding Machine”, Western Stamping Co, Jackson, Michigan
8 slides, 9 digit display
5.5 x 3.3 inches
Steel & plastic
With red/clear vinyl wallet, metal stylus with plastic ends, and instructions
1950s
This is identical to the later type of Baby Calculator, seen above, except for the printing on the face plate and the type of case.
Consul the Educated Monkey (Reproduction)
The original was patented in the USA in 1916. Moving Consul’s feet to point to two numbers results in the answer being shown in the window between his hands. The original was supplied with cards which also enabled addition, subtraction and division to be carried out but the reproduction is not. The original was made in the USA - the reproduction does not say where it was made - it came in a cream coloured card box with transparent section in the lid.

Buyer Beware - I bought mine on EBay; it was listed under Antiques - Scientific Instruments and, although the seller gave the condition as new he did not state that it was a reproduction. Fortunately I had only paid a little more than its actual worth.
“Baby Calculator”, made by the Calculator Machine Co, Chicago
7 slides, 7 digit display
6 x 3.4 inches
Steel
With leathercloth wallet and stylus
1920s/1930s
Obtained from the USA
“Baby Calculator”, made by the Calculator Machine Co, Chicago
8 slides, 9 digit display
5.5 x 3.3 inches
Steel & plastic
With card box
1940s/1950s
Obtained from Canada
“Ve-Po-Ad”, made by the Reliable Typewriter & Adding Machine Co, Chicago
8 slides, 9 digit display
5 x 3.3 inches
Steel
With wallet
Circa 1940
Obtained from the USA
“Ve-Po-Ad” was derived from “Vest Pocket Adder”
“Addometer”
Reliable Typewriter & Adding Machine Co, Chicago
8 dials, 8 digit display
Steel; 11.5 x 2.3 inches
With stylus
Mid 20th century
Obtained from Germany
“Addometer”
Reliable Typewriter & Adding Machine Co, Chicago, and
Taylor’s, 74 Chancery Lane, London (who milled out the Reliable company’s name and address and stamped their own in its place)
8 dials, 8 digit display
Steel; 11.5 x 2.3 inches
With stylus and case “Manufactured in England”
Sterling currency version; red dials for shillings and last two dials for pence and halfpennies/farthings respectively.
Mid 20th century
“Addometer” model A fractional-decimal
Reliable Typewriter & Adding Machine Co, Chicago
8 dials, 8 digit display
Steel; 11.5 x 2.3 inches
With stylus, case and instructions
The last dial is divided into eighths
Mid 20th century