Universal Planimeter by Ott, 1925, made in Germany For Sale

As the name says, this is a universal planimeter, which means that it can be used as either a polar planimeter, a rolling planimeter, or a radial planimeter. This planimeter was made by A. Ott, in Germany, but was apparently sold by \"H. Wild A.G.\" in Heerbrugg, Switzerland. The original instructions, in German, are included. I’ve posted pictures of the cover of the instructions and three illustrations from them showing the different ways the planimeter can be configured. I’ve also included pictures showing it setup in polar and rolling configurations. I failed the test to assemble it in radial configuration, probably because I can’t read German.
This planimeter is in magnificent condition, the only exception being some light surface corrosion on the steel rollers, which is shown in the pictures.
This planimeter 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 medium flat rate box within the USA. Shipping charges will be somewhat higher for destinations outside the USA.