light+bulbs

The bulb designs and filaments varied widely. Early carbon filaments were made of carbonized cardboard, bristalboard, and cotton string. Next came carbonized bamboo and next asphalted carbonized bamboo. Next was carbonized squirted cellulose. Then there was high temperature carbonized cellulose known as the GEM filament. Produced for a short time were osmium and tantalum filaments. Next came non aligned tungsten and finally the drawn tungsten filament of today's incandescent lamp. The purpose was to develop more efficient filaments, which gave long life with more light for less watts. Originally there were evacuation tips on top of the bulbs. It was very difficult to remove the air from the base of a bulb, although it could and was done for lamps requiring special optical characteristics, although they were comparatively expensive. Commercially tipped bulbs were no longer produced in 1923 when a cheaper base evacuation method was developed. A notable fact was the lead in wire in the glass tube between the base and filament were made of platinum.

Fluorescent bulbs use a heated plasma to produce UV light that is then transformed into white light. These bulbs come in a variety of shapes and sizes, including the small, spiral-shaped bulbs marketed in many stores as low-energy