1906

During this year, tantalum filaments were introduced.  A tantalum filament consisted of a single long strand that was metallic in appearance and slender or finer than that of a carbon filament.  It was threaded or strung between two levels of numerous wire hooks or arms attached radially around the upper and lower portions of the button rod, giving a squirrel cage like look.  The filament may continue onto a second or third cage.  Each arm supporting the filament has an aesthetically looking curved hook at the end, giving a pleasing ornamental look to the interior of the bulb.  Lamps with these filaments were used mostly for DC (or Direct Current) circuits, of which only a few cities provided at the time these lamps came out.  Most other cities at the time were using AC (or Alternating Current) circuits for the homes.*  Hence tantalum lamps were sold in low quantities and production of these lamps did not last very long.  After seven years on the market, the lamps were discontinued in 1913.  Because of this very short period of use, tantalum lamps are quite rare.

* Today, all homes in this country are provided with AC or Alternating Current.”

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