Stephenson Adder Type 2, Adding Machine
Item History & Price
| Reference Number: Avaluer:4701 | Maker: A. M. Stephenson |
The Stephenson Adder was patented in 1873 by A. M. Stephenson, a man who was, at various times, a railroad agent, a clerk, a traveling salesman, and a printer. Part of his time as a traveling salesman (during which he visited every state and territory of the USA, twice) was no doubt spent selling his own invention, this adder. This is an interesting adder. It takes input only on the right dial, which has 10 digits. The left dial has 20 positions, 0 through 19.&n...bsp; In use, the left dial is turned only when the right dial performs a carry, giving the Stephenson the ability to count up to 199. The stylus hole in the left dial is only used for clearing. This is not an adding machine, it is a column adder. Construction is extremely simple. Having the two wheels turn in opposite directions allows for a simple pawl (part of the right wheel) and spring detent on the left wheel to suffice for a carry mechanism. There are no detents on the right wheel, which turns smoothly. The front and back covers appear to be stamped nickel-plated brass. The spring for the detent on the second wheel is anchored in a hole in the back of the case. Six rivets hold the case together and two more serve as pivots for the wheels. The whole machine is barely thicker than a US Nickel (that’s a $0.05 coin, for my friends around the world). The Stephenson Adder was sold from the early 1870's until the late 1920's, an incredibly long run for a mechanical calculator of any sort. This Stephenson adder is generally referred to as a “Type 2”, being distinguished by the embossed pattern on the front, as opposed to the completely flat Type 1.
This particular Stephenson Adder has the Joliet, Illinois address on the back, one of the three addresses used by Stephenson. It is not known what chronological order those addresses fall into. While this adder is a bit dirty, there is very little wear to the nickel plating, even on the high spots. I find this surprising considering that this small device was intended to spend all its time in someone’s vest pocket. It works perfectly.
This adder is from the collection of Robert K. (“Bob”) Otnes, PhD, one of the founding members of the Oughtred Society and the original editor of the Journal of the Oughtred Society. It is being sold by the Oughtred Society on his behalf.
The Oughtred Society was founded in 1991 by a group of slide rule collectors and is dedicated to the preservation and history of slide rules and other calculating instruments. Membership is open to anyone. Further information about the Oughtred Society can be found at: http://www.oughtred.org/.
PayPal is the only accepted form of payment. Buyers within California will be charged 7.25% sales tax.
Shipping will be by USPS Priority Mail. Shipping charges will be somewhat higher for destinations outside the USA.
This particular Stephenson Adder has the Joliet, Illinois address on the back, one of the three addresses used by Stephenson. It is not known what chronological order those addresses fall into. While this adder is a bit dirty, there is very little wear to the nickel plating, even on the high spots. I find this surprising considering that this small device was intended to spend all its time in someone’s vest pocket. It works perfectly.
This adder is from the collection of Robert K. (“Bob”) Otnes, PhD, one of the founding members of the Oughtred Society and the original editor of the Journal of the Oughtred Society. It is being sold by the Oughtred Society on his behalf.
The Oughtred Society was founded in 1991 by a group of slide rule collectors and is dedicated to the preservation and history of slide rules and other calculating instruments. Membership is open to anyone. Further information about the Oughtred Society can be found at: http://www.oughtred.org/.
PayPal is the only accepted form of payment. Buyers within California will be charged 7.25% sales tax.
Shipping will be by USPS Priority Mail. Shipping charges will be somewhat higher for destinations outside the USA.
