Rare English Drysdale Potentiometer 1915. Johns Hopkins Fine Complex Instrument for measuring current AC DC exc Start Price USD 250.00 Current Price USD 260.00 Time Left - Bid Count 3 Buy It Now Price - Reserve Price - Start Time Sunday, November 30, 2008 End Time Sunday, December 07, 2008 Location Elkins Park, Pennsylvania See more about 'Rare English Drysdale Potentiometer 1915. Johns Hopkins' Description This is a very rare potentiometer of Dr. C.V. Drysdale. Made by Tinsley and Co. London in 1915. This unit was purchased by Johns Hopkins University in 1915. It was in that department until 1977!! I have all of the records of its use from 1915. It originally cost Hopkins $498!! This amazing device has all sorts of "bells and whistles." It has dials, connectors galore. I am not sure exactly how it was used but I believe it was used to measure AC and DC current and in medical devices, possibly quack medicine. It is not my area of expertise. I do know that it is very rare. I can only find one other on the net and it is in a museum in Canada. I can't imagine this device being in much better shape, other than a crack in the top of the box. The box is 34X16X7 inches. This device is heavy but I will ship it at cost anywhere in the world. It really belongs in a museum of early electrical devices. Makes a fantastic display. Please ask any questions and I can send more photos if needed. Payment by check,money order, or paypal. Buyer pays shipping fees. Note that the automatic ebay shipping calculator does not work on this item as it is too heavy.  Add 6% tax if in PA and without a resale number.   Check out my feedback and you know it will be a safe transaction. My website is medicalantiques.com  Have a look at my other listings of fine antique medical and surgical instruments as well as books related to the history of medicine. Update: A helpful ebayer reocmmended doing a search on google books for drysdale potentiometer 1915. Voila! Lots of interesting period information! Let me know if you need the links. Thank you! Place a Bid!