The danger of fire and explosion in coal and other mines has always been present, though nowadays the problems have been considerable reduced. Early in the last century, however, mine disasters caused by the accidental ignition of methane gas were far more common. The invention of a safety lamp by Sir Humphry Davy about 1815 did much to cut down these risks.
Humphry Davy, well known at the time as one of Britain’s leading chemists, realised that the problem of designing a safety lamp centred on the intake of oxygen and the dispersal of heat. A flame must have oxygen in order to burn, but the heat generated by the flame will normally ignite any combustible gases around it. With characteristic ingenuity the scientist decided to enclose the flame of an oil lap with a ‘wall’ of wire gauze. The result was that air could reach the flame, whilst the heat produced by burning was largely dissipated before the spent air came into contact with gases outside the lamp. The light of the flame, though slightly dimmed by the gauze, was still adequate. In later versions of the lamp precautions were taken to ensure that the gauze could not be removed while the lamp was alight. Safety lamps of the Humphry Davy type are still in use, though without doubt the advent of the electric light bulb has reduced their importance as a means of detecting the presence of dangerous gases since the lamp flame is affected by them.
The achievements of Sir Humphry Davy (1778 – 1829) were by no means confined to the invention of the safety lamp, important though this was. He became widely known as a researcher and lecturer at the Royal Institution (where he worked with Michael Faraday). Amongst his successes in the field of chemistry, his isolation of potassium, sodium, barium, boron and calcium and other substances ranks high. So does his proof that chlorine is an element. He carried out an investigation into the anaesthetic effects of nitrous oxide (laughing gas) at considerable risk to himself. Together with Faraday much of his research in later years was concerned with electro-magnetism.
Like the majority of early scientific workers Humphry Davy did not restrict himself to any specialised group of studies, and the wide range of his interests is not easily described in so brief a summary. The high esteem in which he was held by his contemporaries can, however, be inferred from the numerous honours which he received during his lifetime. Humphry Davy was made a knight in 1812, and later became a baronet. The crowning scientific honour came in 1820, when he was elected as President of the Royal Society.