Historical information

Before the introduction of electricity, irons were heated by combustion, either in a fire or with some internal arrangement. An "electric flatiron" was invented by American Henry Seely White and patented on June 6, 1882. It weighed almost 15 pounds (6.8 kg) and took a long time to heat. The UK Electricity Association is reported to have said that an electric iron with a carbon arc appeared in France in 1880, but this is considered doubtful.
Two of the oldest sorts of iron were either containers filled with a burning substance, or solid lumps of metal which could be heated directly.
Metal pans filled with hot coals were used for smoothing fabrics in China in the 1st century BC. A later design consisted of an iron box which could be filled with hot coals, which had to be periodically aerated by attaching a bellows. In the late nineteenth and early twentieth centuries, there were many irons in use that were heated by fuels such as kerosene, ethanol, whale oil, natural gas, carbide gas (acetylene, as with carbide lamps), or even gasoline. Some houses were equipped with a system of pipes for distributing natural gas or carbide gas to different rooms in order to operate appliances such as irons, in addition to lights. Despite the risk of fire, liquid-fuel irons were sold in U.S. rural areas up through World War II. In Kerala in India, burning coconut shells were used instead of charcoal, as they have a similar heating capacity. This method is still in use as a backup device, since power outages are frequent. Other box irons had heated metal inserts instead of hot coals.
From the 17th century, sadirons or sad irons (from Middle English "sad", meaning "solid", used in English through the 1800s[4]) began to be used. They were thick slabs of cast iron, triangular and with a handle, heated in a fire or on a stove. These were also called flat irons. A laundry worker would employ a cluster of solid irons that were heated from a single source: As the iron currently in use cooled down, it could be quickly replaced by a hot one.

https://en.wikipedia.org/wiki/Clothes_iron

Significance

This iron is typical of the clothes iron used before electric irons superseded it.

Physical description

Salter iron no. 6, painted black but with rust showing through.

Inscriptions & markings

Salter iron no. 6.