Spirit Lamp, Polyhedral Shaped, Glass

Advanced, beam engraved with a rider scale, for use with 10 mg rider, balancing nuts, agate bearings and knife edges. Fitted on a wooden board in a polished wooden case. Capacity 200 gm, sensitivity 0.5 mg.

100 mm dial graduated from 28” to 31” and 940 to 1040 millibars, with an index pointer, with transparent top cover, mounted in plastic case 160 mm dia approx.