If you have been following the unfolding saga of Weather Eye in recent days, you will know that I am in Sweden. Last evening I had dinner in the Lofstadt Slott in Norrkoping, the house once owned by Count Axel von Fersen, whose name, perchance, may ring a tiny bell.
Alex, you may recall, nearly caused a revolution, and perhaps he did, by virtue, if one might use the word in such a context, of an alleged intimacy with Marie Antoinette, then queen of France. But meterologists have no truck with idle gossip of this kind. In Sweden, I only think of Anders Celsius.
Celsius, like Axel, was a Swede. He was born in Upsala in 1701, and by the age of 29 was professor of astronomy at Upsala University, where he delved into the mysteries of many of the physical sciences of his day.
In 1736 he joined an expedition to Lapland to measure the length of an arc of longitude, and his findings verified Newton's theory that the Earth was flatter at the poles than at the equator. He was also a keen observer of the aurora borealis, and is credited with being the first to associate it with the Earth's magnetic field.
But the immortality of Celsius's name was assured in 1742 when he presented to the Swedish Academy of Sciences a paper entitled Observations About Two Fixed Degrees on a Thermometer.
In his discourse he proposed a temperature scale that was defined by two temperatures that could be identified objectively without great difficulty: the boiling point and the freezing point of water. The interval between them was divided into 100 equal parts, and he referred to them as "degrees".
Now the temperature scale proposed by Anders Celsius had one very surprising feature: it was the reverse of the Celsius scale we know today. His suggestion was that 100 should be the freezing-point of water, and zero be its boiling point; he justified its topsy-turvy nature on the grounds that it avoided the use of the minus sign in winter.
In the decade following its announcement, somebody turned the Celsius scale the "right" way up, but no one knows for sure who it was. Some say it was Celsius's colleague, Carl Linnaeus; others that it was his successor, Martin Stromer; and yet another school of thought attributes the rectification to a French man from the town of Lyons, called Cristin.
Be that as it may, we do know that Celsius died at Upsala in 1744, aged only 43, a mere two years since he had unveiled the centigrade scale that still bears his name today.