Adall Adder / Adding Machine
Item History & Price
Reference Number: Avaluer:4787 | Maker: The Adall Co. |
To my mind, the Adall is an exceptionally clever adder, or rather, it was very cleverly designed to be quick and easy to use, while having a very small number of parts. It consists of two stamped aluminum discs, one of which, the outer disc, is the disc you hold in your hand with your thumb going through the ring on the back. The inner disc, as the name implies, rotates within the first disc. The inner disc has a spiral groove in which an indicator rides, with the spi...ral moving the indicator along a slot in a fixed arm as the disc rotates. The outer rim of the outer disc shows the numbers from 1 to 99, and the outer rim of the inner disc has “gear teeth” to engage the included stylus. To add a number, insert the stylus in the gear opposite the number you wish to add, and turn the inner disc clockwise until the stylus encounters the stop (the fixed arm). Repeat until all desired numbers have been added. The last two digits of the sum will be shown in the small window at the end of the fixed arm, and the third digit, the hundreds, will be shown by the position of the indicator along the slot in the fixed arm. The maximum total that the Adall can handle is 1199, which seems a bit limiting until you remember that this is really a column adder that is meant to add two columns at a time with the indicator giving the carry.
The design of the Adall is remarkably similar to a German adder called the “Optima” that dates from 1910, and if we can believe the text, “Made in Bavaria, ” on the shaft of the stylus, it is entirely possible that the Adall was made in Germany for “The Adall Co.” in Birmingham, UK. Confusing the issue of origin, examples of this same adder has been seen marked “Adal” instead of “Adall.” According to Martin, the Adall appeared in 1910 and was long since gone by 1925.
I would say that this Adall is in overall good condition, with some pluses and some minuses. On the plus side, it includes both the original instructions and the original stylus. On the minus side the indicator is not original; it is a very homemade-looking brass replacement, but it is the correct shape. Also on the minus side, the outer aluminum disc is bent. The bend is not serious enough to affect function, but it is unsightly from certain angles, especially the one I took the picture from, which if anything, exaggerates the bend. The aluminum of both the inner and outer discs is quite thin, and also a very soft alloy.
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.
The design of the Adall is remarkably similar to a German adder called the “Optima” that dates from 1910, and if we can believe the text, “Made in Bavaria, ” on the shaft of the stylus, it is entirely possible that the Adall was made in Germany for “The Adall Co.” in Birmingham, UK. Confusing the issue of origin, examples of this same adder has been seen marked “Adal” instead of “Adall.” According to Martin, the Adall appeared in 1910 and was long since gone by 1925.
I would say that this Adall is in overall good condition, with some pluses and some minuses. On the plus side, it includes both the original instructions and the original stylus. On the minus side the indicator is not original; it is a very homemade-looking brass replacement, but it is the correct shape. Also on the minus side, the outer aluminum disc is bent. The bend is not serious enough to affect function, but it is unsightly from certain angles, especially the one I took the picture from, which if anything, exaggerates the bend. The aluminum of both the inner and outer discs is quite thin, and also a very soft alloy.
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.