Non-Electric Lights
Candles were placed on tree branches by melting the bottom so they would stick to the wood. Metal candleholders were made in Germany had a clip on the bottom to make the candles more stable, but they were still dangerous. In England, glass manufacturers made small cups from colored pressed glass with quilted patterns on them. They were filled with oil and a wick, suspended from the branches with copper wire and called candle cups or fairy candles.
Electric Lights
The first inventor placed electric pear-shaped, colored lights on his parlor tree in 1882. His name was Edward Johnson and he worked with Thomas Edison. These lights didn't come in strings--each was individually hand-wired on the tree. He created the first mass-produced strings of lights in 1890. Electric Christmas lights did not become the primary method of lighting a tree until after World War II.
Pre-Wired Lights
In 1903 General Electric made small carbon filament lamps and wired them together to make the precursor of modern Christmas lights. American Ever Ready soon followed. Mazda lights, made by GE, were named after the Persian goddess of light, and in 1912 they were made with tungsten that lasted much longer than carbon filament lights.
Shapes
The first lights were pear shaped and had an exhaust tip at the top to let heat escape from the bulb. In 1910 lights were made in a globe shape. Cone shape lights came into being in 1920 and continued in all sizes until 1970 when twinkle lights made an appearance. In the 1930s, some lights came configured in shapes. The star and rosette shape were the most prominent and were painted, glittered and decorated with colored glass.
Figurals
The Kremenetzky Company in Austria was the first to make figural Christmas lights in 1909. These lights were pressed into shapes of animals, fruit, baskets and other objects. They were painted with much detail and the only problem was that because of the heat the paint flaked. Those found today are often missing much of the original paint.
Novelty Lights
During the 1930s to the 1950s lights included figures of stars, Angels and Santa. These figures were lit and used as tree toppers. In 1948 the bubble light was produced by NOMA. A glass tube was connected to a plastic base with a light that caused the liquid in the tube to get hot. Methylene chloride was in the tube, enabling the water to boil at low temperatures, making bubbles continually rise to the top of the tube.
Collecting and Using
Many pre-wired Christmas lights can be found in antique shops and online. Some sets cost less than $20, but can be more expensive if in the original box. Most boxes are cardboard with sections for each bulb or they have a cardboard holder to hold the lights in place. The oldest electric lights that had to be individually wired are very hard to find. The original box was usually made of wood and had sections for each bulb. These are very hard to find and very expensive. The figural light bulbs are plentiful and can cost anywhere from $5 to $25. It is not advisable to actually use antique lights on a tree. The wiring needs to be checked, and the lights get too hot for an artificial tree.