During the days of the sintered tungsten filament lamp, that is, from 1907 to about 1909, the wire had a tendency not to maintain its original length. The filament segments in the new lamp drooped considerably when the lamp was burned in any position. One manufacturer designed a lamp that was meant to reduce the problem of droop. It was introduced first in Europe and then later in the United States. The Just lamp is shown to the left.
Quoting from an article with the above title (Electrical World, Vol LII, No 10, Sep 5, 1908, pg 542):
"...In this type the entire filament structure is supported by springs. The central glass rod that carries the two end spiders is attached at both extremities to spiral springs, secured respectively to the leading-in glass protection and to the opposite end of the bulb. The attachment of the filament to the leading-in wires is also flexible. This method of mounting not only permits the lamp to be used at any angle, but renders it less apt to breakage when installed in vertical position. The lamp at present is made only in 25 and 40 cp.Perhaps a later design is that shown in the photograph below. In it the two end springs have been eliminated and the hairpin shaped sintered tungsten filaments were mounted to apply tension on the loops at the upper end of the lamp. This lamp used porcelain as the base insulator. Etched in a circle around the exhaust tip is: "Just Tungsten Lamp Pat. Pending". Stamped on the brass base is, apparently, the date: 8-12-08. Also stamped is "220/50" and the word "schräg". Loosely translated, this word means sloping or slanting."...The Electrical Accessaries Company, 1135 Broadway, New York, represents in this country the Just lamp..."
