Chemical Composition: ICP-MS/AAA data from sample, Leaded Bronze:
Cu, 79.76; Sn, 6.75; Pb, 12.99; Zn, 0.024; Fe, 0.03; Ni, 0.05; Ag, 0.03; Sb, 0.04; As, 0.25; Bi, less than 0.025; Co, 0.076; Au, less than 0.01; Cd, less than 0.001
J. Riederer
Technical Observations: Six of the seven lamps (1920.44.181, 1965.87, 1977.216.3406, 1977.216.3407, 1977.216.3423, 1978.495.32, and 1992.256.93) have mostly green patinas. 1977.216.3407 is mostly brown and black with areas of dark green. 1977.216.3423 has a large area of blue. 1978.495.32 and 1920.44.181 are more mineralized, and large lumps of raised corrosion products obscure the finer details of their surfaces. 1920.44.181 has lost the tip of its spout and much of its handle due to its fragile, mineralized condition.
All of the lamps except 1977.216.3406 were cast, presumably using a lost-wax technique. The interior surfaces generally conform to the exterior profiles, including the small feet, and it is likely that molds were used to form the wax models of the main portions of these lamps. The perfectly circular central elements may be the result of using a wheel to create the original models from which the wax casting molds were made. These shapes were then altered manually to form the spouts and decorative elements. The handles were probably added manually to the cast-wax body models. The rather substantial handle of 1965.87 could easily have been molded at the same time as the body of the lamp, although there is no indentation in the interior to prove this. The separately cast lid on this lamp is intact and held in place with an oversized—but seemingly original—copper alloy pin.
The bowl section of 1977.216.3406 is so thin and its interior surface is so smooth that it appears to have been raised rather than cast. Its thickness varies between 0.5 and 1.0 mm. An x-radiograph of the lamp reveals distinct hammer marks, which confirm that the surface was raised. The cast base is attached with lead solder. Its shape is perfectly circular, implying that its model was turned on a wheel. A projecting rim at the bottom of the base indicates that it was attached to a larger base section or mount. Solder is also present there and at a spot at the back of the lamp, where a handle had been attached but is now lost.
The exterior surface of 1920.44.181 has elongated fiber-shaped carbon inclusions embedded in its corrosion products. All of the lamps, except 1977.216.3406, appear to have oil residues mixed with accretions and corrosion products in their interiors.
Henry Lie (submitted 2001)
