hard to find early 20th century fully enclosed “a-b” hanging copper arc lamp designed and patented by thomas e. adams for the adams-bagnall electric co., cleveland, oh. mr. adams was considered an expert in erecting and repairing general electric light apparatus. during the 1880′s he patented numerous improvements on electric light and railway systems, including the wood segment commutator of the brush dynamo; the brush-adams arc lamp, the double pole trolley, etc. in 1895 he became associated with others (former workers of the brush/swan incandescent plant) in the organization of the adams-bagnall electric company. the interior vintage industrial single carbon arc lamp contains a very unique fluted and ruffled pressed copper housing that has been lightly polished. the upper carbon holder, rheostat, two spools, armature, air pot and clutch rods were removed. the lamp housing contains a single threaded rod with single porcelain socket base for use with standard incandescent light bulbs. when the lamp was originally electrified, the electromagnets pull the two carbon rods apart, establishing an arc. when the carbon rods burn down, the dashpot prevented contact between the upper and lower rods. amazingly, the ornamental shade fitter and original bulbous clear glass globe remains intact and free from damage. measures 12 x 32 inches.