Signal Marker Pen
Accession Number: 2012.psy.102
A small metal instrument based around an electrically-actuated stylus. The stylus would be mounted over the poles of an electromagnet and actuated by an electrical current. The reach of the marking stylus can be adjusted along the length of a rod. A screw clamp attaches the instrument to a vertical stand. The instrument is largely made up of brass and steel with the stylus itself made of a stiff, light material, probably a natural fiber. The instrument is housed in a form-fitted velvet-lined black case secured by a silver clasp.
Primary Materials: Steel, Brass, fibre
Manufacturer’s label bottom left corner of case: “E. ZIMMERMANN/Leipzig/Emlien? Strasse 21.” A second manufacturer’s mention comes in the form of an engraving on one of the sides “E. ZIMMERMANN/LEIPZIG. The opposite side of the instrument has the number “12” engraved.
Case: Height = 3.5, Width = 8.5, Length = 24.5; Instrument: Height = 1.5, Width = 7, Length = 21
The signal marker recorded timing marks on a rotating kymograph drum. It would have received its electrical signal from a timing device such as an electrically-driven tuning fork. The marks made by this stylus would have been used to calibrate those of other markers which were connected to stimulus and response apparatus.
Fair: The body of the pen is in good condition. The case has suffered prolonged exposure to light, which has caused it to fade and fray. The stylus of the pen is broken.
Manufacturer: E. Zimmermann, Leipzig
Date of Manufacture: c. 1920
Dept. of Psychology, University of Toronto
“Highly suited to record tuning fork oscillations and other small temporal intervals. A spring, serving as anchor, is mounted over the poles of an electromagnet whose oscillations are magnified by means of a spring-like device. The poles of the electromagnet are contacted by means of a screw from below. The pressure of the stylus on the drum can be guided by means of a second setting. This signal can tolerate stronger currents because of larger magnets and has the lowest possible latency because the anchor (spring) does not touch the poles.
The apparatus has a low profile and therefore has the advantage of much lower height than the original Pfeil version. The signal therefore affords maximal use of the writing surface because it can be positioned closely under other writing or recording devices. The moving parts are held to a minimum so that the apparatus is capable of handling easily up to 250 double oscillations per second.”
[Zimmerman, 1922, Translated by Prof. Rolf Kroger, Psychology Department, University of Toronto]
1) Zimmermann, E. (1922) Catalogue “Fabrik Wissenschaftlicher Apparate, Liste 41,” Item No. 1830, Leipzig-Berlin.