The stories behind the words

On a cold, damp evening during the Christmas season of 1860, an expectant crowd gathers in the gas-lit gloom outside the Royal Institution in London. They shuffle into the steep banked seating of the auditorium and an excited hush descends as Michael Faraday enters and begins the first of his six lectures on the chemical history of a candle. As he commences his exploration and ignites the audience’s curiosity, he remarks:

‘But how does the flame get hold of the fuel? There is a beautiful point about that – capillary attraction. “Capillary attraction!” you say – “the attraction of hairs.” Well, never mind the name; it was given in old times, before we had a good understanding of what the real power was.’¹

With this remark, Michael Faraday has provided a flicker of illumination on the theme of this article: the potential for words in science to promote understanding or to confuse and obfuscate. When Faraday introduced the term ‘capillary attraction’ to his audience, he immediately dismissed it as misleading because of its reference to hairs (capillaris is the Latin word for hairs). He states the term was assigned when the true ‘power’ (another interesting choice of word), or mechanism, was not known. This suggests he thought the term was initially assigned because it was thought the movement of the liquid was caused by the attraction of tiny hairs on the surface of the wick.

I have used capillary attraction as an example to show there are several potential routes to develop understanding of a scientific term. The literal meaning and knowledge of the Latin origins of the English word is the first route. Often, this is a successful route, but in this case it leads to an incorrect conclusion, as Faraday demonstrated.