Flickering flames

Leroy Thwing, 'Flickering Flames', l974.

Since prehistoric times grease and oil lamps have been used to light homes. Crudely fashioned hollowed out stones were used to burn animal fat. As time progressed seashells were adapted for hanging oil lamps.

These were the prototypes of the floating wick oil lamps and spout lamps, whose simple and functional designs did not change over centuries. The oil lamps made by the ancient Greeks and Romans were of a form still recognisable in lamps being produced in the late 18th century. They also gave the same amount of light which, for a single spout oil lamp, was about equal to one tallow candle.

Oils from animals, vegetables and minerals were used for lamp fuel. They were generally sourced from whatever was available locally. In Mediterranean regions this was olive oil. For the poor cottager in Britain, if there was oil to be spared from food, it was likely to have come from fish. The wealthy could afford superior imported oils.

Until paraffin oil became widely available, the difference in quality of oils was similar to that between tallow and wax candles. A higher price meant more light and less smell and smoke. In l709 the tax imposed on candles was also levied on oil except from fish which, like rushlights, was exempted in recognition that this oil was a light of the poor.

For centuries malodorous fish, whale and seal oils had been used for lighting, particularly by people living in coastal areas and near ports. These oils provided a light for all those who were fussy neither about the smell nor the smoke, which left greasy black deposits.

The finest and most expensive whale oil that produced a good light with little smell came from the sperm whale. It first became available in Britain in about l750. In l784 the price of spermaceti oil was 4s 6d a gallon, but increasing demand created shortage and in l788 the cost had risen to 7s 6d a gallon.

As demand for spermaceti oil outstripped supply, a more economical solution was to use an oil that could be produced in quantities at home or was cheap to import. Colza oil was a quality alternative. The oil was extracted from rape seed, Brassica campestris. It was slow to deteriorate and produced a clear, bright, smokeless flame.

However a disadvantage with many oils was that their thicker consistency did not easily allow for capillary action to take the oil to the top of the wick, especially with colza oil which was viscous. These factors had implications for lamp design. It was subsequently found that lamps fitted with Argand burners, first patented in l783, performed better if the oil reservoir was placed above the height of the wick.

The Argand burner was described by its inventor, Ami Argand (l750-l803) in his English patent application, as 'a lamp that is so constructed to produce neither smoke nor smell and to give considerably more light than any lamp hitherto known'.

The burner comprised a wide, cylindrical woven wick held between two concentric metal tubes. This increased the air supply to the wick and allowed for full aeration of the flame, which was still further increased by the addition of a glass chimney. In terms of light output the lamp had no rivals as it claimed to produce illumination equal to that of ten wax candles, 10 cp, and if used with a quality oil and properly maintained, it produced a bright light.

The discovery in l859 of vast mineral oil deposits in Pennsylvania led to the world's markets being flooded with cheap and plentiful supplies of paraffin (kerosene). Unadulterated paraffin lamp oil was stable. It produced a flame of good colour, was practically smokeless and had only a slight smell. Moreover, as the oil was thinner, it travelled by capillary action in sufficient quantity to the wick. This led to a change in lamp design as the reservoir could now be placed below the wick.

Paraffin lamps were initially fitted with single wick burners. However, in 1865 the invention of the Duplex burner by James Hinks increased illumination significantly to 30 cp. The Duplex burner comprised of two parallel flat wicks separated by about an eighth of an inch. The burner produced a brighter flame with greater economy, and from the time of its introduction until the present day it has been used extensively on all but the cheapest paraffin lamps.

Throughout the last decades of the 19th century numerous lamp patents were taken out to improve the illumination, economy and safety of paraffin lamps. Many lamp developments concentrated on improving airflow to increase combustion and light. It was the central draught lamp that succeeded. Its technology was derived from the Argand lamp. These lamps were fitted with air diffusers or spreaders, and although some claimed illumination output of up to 200 cp, those mostly used in the home provided up to 50 cp.

In the late l890's Welshbach's incandescent mantle, originally developed for gas lighting, was used with oil lamps; light output rose to 80-100 cp and it was possible to convert Duplex lamps by changing the burner. The final advance in the early 20th century was in pressure lamps like the Tilley lamp, which are still in use.