SOLO Manual Direct Adding Machine - Chadwick Comp., Japan 1970.
A finger pulls or pushes the dials up (subtract) or down (add) while tens carry automaticcally. A general reset is done by pushing the lever on the left side of the machine. This simple adding aid is rather lightweight and made of green plastic. The counting mechanisme is simplex-type. The machine was also manufactured in Germany with the brand name Neckermann. Dimensions: 12x9x9 cm.

Thales Talisman - Thaleswerk, Rastatt, Baden, Germany 1955.
Adding machine type KA with R(epeat) lever for adding many numbers. A Plus/Minus lever to choose between add and subtract. Input is done by pushing tilted keys in a 9 x 8 matrix. The big metal button to the left is for resetting the input keys. Calculation by pushing down the big lever.

BOHN CONTEX-10  Brdr. Carlsen A/S Birkerød, Denmark 1964.
The Contex Model 10 is a miniaturized and simplified version of the large electro-mechanical calculators (such as the Friden STW) that were the mainstay for calculating in the '50's and '60's. The Contex 10 is an entirely manual calculator, operating by 'people power' only.

Sum-it Adding machine - Pearl Engraving Corp., New York , 1950.
8 Columns, decimal. Additions only. Operated directly by finger pressure on toothed discs. Adding results appear in the register at the top of the machine and is cleard by a full, clock wise turn of the handle on the right. Also: an automatic tens-carry mechanism. The machine has a die-cast alloy casing with plastic setting discs and register dials.

Resulta E 7 - Maschinen- und Werkzeugfabrik Paul Brüning, 1963.
Very nice adding and subtacting machine. Dimensions: 17x11x8 cm. Rather smooth mechanism. Stylus operated. The reverse lever to the left allows subracting. The reset lever to the right must be pulled for zeroing the registers. At the right side is an other small lever to hold the adding registers for cumulative additions. At the backside a small illustrated operator's manual.

Resulta BS7 - Maschinen- und Werkzeugfabrik Paul Brüning, 1963.
Sevendrums with stepped stylus grooves for the digits 1-9, a lever to select addition or subtraction. Very small and often mistaken for a toy. Operated by poking a metal stylus into the digitholes. Bought on a collectors fair in Holland in 1991 for 15 Dutch guilders (7 Euro).

Summira - Germany 1942. Paul G. Müller, Roisdorf Bonn Germany 1951.
Like the Resulta above but this portable adder can be manually operated by pulling gear-wheels. The bar in front releases the gear-wheels. The button to the right clears the registers.

TriumphaTor - Triumphator-Werk in Leipzig-Mölkau 1957.
The manufacturer specialized in Odhner-like adders but the competition was fierce and the TriumphaTors were relatively expensieve. To compensate
these smaller and cheaper portable adders were mass-produced.

ADDIPRESTO adding machine - Brevetti Lanza-Savona, Italy 1965.
Light-weight pin-operated adder in plastic housing. Also marketed as the Swift Handy Calculator. On the right the red pin to operate the machine and to the left the reset-lever to clear (zero) the counting mechanism.
Variations are Addietta and Addimat.

Wolverine Toy Adding Machine - Wolverine Supply & MFG Co. USA 1940.
Educational Adder made of tin with a very simple mechanism. The machine is operated by putting an indexfinger into a numbered hole and press it downward as far as it will go. By repeating this action additions are made. There is no reset mechanism. Resetting by 'adding to zero' the registers.

Speedee Add-A-Matic Half-keyboard adder. CM Inc. Boston. 1971.
Japanese version of the Danish Contex. The British-looking blue-green cover with the inscription 'CM Inc, Chadwick' is made of bakelite. The print on the original box indicates that the machine was manufactured in Japan for Chadwick Miller Inc. of Boston. The machine is identical to the Contex.

Burroughs Direct Adder - Class 6 Adding Machine. Burroughs Comp. 1938.
Small (28 x 15 x 12 cm), lightweight and portable machine for quick direct additions only. The metal display shows six digits, 999.999 as the highest number. These machines were heavily used by shop keepers in stead of expensive cash registers. Scientists used them for counting samples.

Burroughs Adder - Class 5 Adding Machine. Burroughs Comp. 1918.
This Burroughs direct adding machine was very similar to the Comptometer. So similar that Burroughs was apparently sued over it. The machine provided essentially the same functions and feel but with a slightly smaller foot print. This adder is far less heavy than its Comptometer-competitors.

Comptometer - Model H 9x10 keys. Felt & Tarrant Mfg. Co. Chicago 1920.
Comptometers are the first calculators with keyboards. If a number is pressed this number is immediatly added to the resultregister. More keys could be pressed at one time. In case of an error the keyboard is blocked.

Refurbed Comptometer - Felt & Tarrant Mfg. Co. Chicago 1920.
Directly operated like the PLUS but on the basis of 10 digits (1 … 09). Keyboard in a matrix of 9x8. The display is underneath the keyboard. The
mechanism is reset by a lever on the right while ringing a soft bell.

ALFA Adding machine - Angelo Sozzi di Aldo Bona Milano 1938
Lots of adding machines like this one were manufactured in Europa and the US during the twenties and thirties. The keyboard in a matrix of 9x10. The lever at the right is for adding and resetting. Results underneath in a clear display. Produced from 1936 - '40 by Angelo Sozzi and Giuseppe Inzadi, from 1940 - '43 by Officine Serio (producer of the Everest machine) and from 1944 - '47 by Aldo Bona.

SUMLOCK Adding Machine - Bell Punch Company Ltd. London. 1949.
Comptometer-like 10-digits desktop  adder in a modern looking  cast iron cover. Colour green.The keyboard comes in a matrix of 9x6.
Made in England and widely sold and used outside England.

SUMLOCK Adding Machine - Bell Punch Company Ltd. London. 1952.
With a keyboard matrix of 9 x 9 this is a larger model adding machine than the one above. These robust and rather light-weight machines were widely used in offices in fifties for adding tasks.

Contex Mechanical adder - Brdr. Carlsen A/S Birkerød, Denmark 1949.
The light-weight machine has a bakelite cover. With the keys, in a matrix of 5x8 digits, the mechanism is directly operated and the results are displayed. The mechanisme give tactile feedback. It works subtile and very precise.