Bircher Corporation, No 627 Spot-Quartz U.V (Wood's) Filter; Joanco Medical Electronics, Point Finder and Stimulator. Model No.4; Hanovia, Light No.504/4

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School of Physiotherapy, University of Otago

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This spectrometer (far right) has a special glass filter (Wood’s filter) which permits the transmission of ultra-violet light rays and cuts out visible and infra-red rays. The spectrometer was likely to have been used in the calibration of ultra-violet machines to ensure the adequate transmission of ultra-violet rays.
The red battery-operated point finder (middle) was used to detect the levels of skin resistance. It was used by physiotherapists to locate acupuncture points or alternatively, to determine the optimal location of points to electrically stimulate muscles or nerves.
The high-pressure mercury vapour bulb (far left) encases two thorium-coated electrodes at each end. It was designed to fit into a parabolic shaped Hanovia ultra-violet lamp. The mercury vapour produces short ultra-violet light rays which were used therapeutically for irradiating superficial infections of the skin and mucous membranes.