Abstract: A method of aligning and gapping arc lamp electrodes is to form a single piece electrode preform with a number of breakable junctions formed therein. The single piece preform is then positioned in the lamp envelope and sealed in place. The central portion of the preform is then removed by causing the breakable junctions to give way. The central portion is then removed from the enclosed lamp cavity, and the lamp sealing is finished by known methods.

Abstract: A double jacket arc lamp is disclosed. A double jacket arc lamp may be formed with an electric lamp capsule having an inner light transmissive envelope with electrical lead extending from the inner envelope through a first seal, and a second light transmissive envelope sealed to the inner envelope at a second seal to substantially surround the electric lamp capsule and form an enclosed volume between a portion of the exterior of the inner envelope and the interior of the outer envelope, and leaving the leads unenclosed by the outer envelope. The lamp leads then pass through only one seal, and have no portions exposed in the intermediate insulating volume. The inner capsule is then aligned once, while still being for the most part protected by a double envelope.