Wednesday, July 31, 2013

Lord Kelvin: Beyond Degrees


William Thomson, Baron
Kelvin of Largs (1824-1907)
Painted by Hubert von Herkomer
It has been a little while since I wrote on someone who gave his name to a unit, so up this week is the eponym of the Kelvin, William Thomson, who is more often referred to as Lord Kelvin, because, for the last years of his life, he was Baron Kelvin of Largs. He did not inherit the title, but was actually the first scientist to be elevated to the House of Lords, and spent most of his life as William Thomson, although he was knighted in 1866, becoming Sir William Thomson. In addition to being the first Baron Kelvin, he was also the last, as he had no heir to succeed to the title. In just a bit of reading about him, I found out that Thomson/Kelvin was interested in all sorts of things, far more than just thermodynamics. These other interests include telegraph signals, navigational aids, and the age of the earth. I have become quite caught up in his and others work on the telegraph, so I initially intended to write this only on his telegraph work, but I have become so excited about telegraphy that I decided to give it a post all of its own. So this post will focus on Kelvin's work except for telegraphy, but look forward next week (hopefully) to a post all about the telegraph, and perhaps another post on Thomson.

So that I can skip on his scientific and engineering work, I'll give only a brief summary of William Thomson's life. He was born in Belfast and moved to Glasgow as a child. He studied at the Universities of Glasgow and Cambridge (where he was on the rowing team). At the young age of 22 he took a professorship at the University of Glasgow and never left, despite other offers. He gave many lectures, including a series at Johns Hopkins University. He also owned a yacht, the Lalla Rookh, built for him in the late 1860s, and several of his inventions were for improving navigation. He published more than 661 papers/communications and took out 70 patents. After his death in 1907, he was buried in Westminster Abbey next to Isaac Newton.

The Lalla Rookh
From The Life of William Thomson by Silvanus Thompson
The Lalla Rookh was a yacht of 126 tons. Thomson was known to take it out for much of the time between the semesters at the University of Glasgow, and sailed around Scotland and even farther afield, such as Lisbon. He also used it to entertain. In 1871 he planned a cruise to the Hebrides and West Highlands with Hermann von Helmholtz, Thomas Huxley, John Tyndall and James Maxwell, though it seems only Helmholtz was actually able to make it. Having the ship inspired twenty five different patented inventions. One of these was a device for correcting compasses when the ship had a metal hull. Another was an improved sounding (depth finding) device, using a wire rather than a rope such that measurements could be taken at speed.

The purchase of the ship may also have lead to his increased interest in fluid mechanics, which occurred in 1867, and was one of the subjects he discussed with Helmholtz on their journey in 1871. But his interest in fluid mechanics had a little remembered result as well--the idea of vortex atoms. Remember, the structure of the atom was not known in the mid-19th century. A common standard for atomic weights was not determined until 1860, and Mendeleev published the first periodic table in 1869. Even then, people didn't know what made up an atom. J. J. Thomson discovered the electron in 1897, and Rutherford's famous experiment which proved the existence of an atomic nucleus was not until 1909, after Kelvin's death, so the question of the nature of the atom was wide open. William Thomson spent considerable time developing the idea of vortex atoms, based on the descriptions of fluid motion made by Helmholtz, who had expanded descriptions of fluid motion to include more irrotational motion. This theory suggested that atoms are vortexes (such as smoke rings) in the ether that makes up space. By around 1883, Thomson began to feel that his theory was not sufficient to explain matter, but he had gotten other scientists thinking about the idea and furthered the field of hydrodynamics.

There is certainly more to be said, and I had hoped to say it, but hopefully that whets your appetite and you will go looking for more information on your own. The references should be quite helpful. And perhaps I will return to Kelvin at some point to talk about absolute zero, electricity, and the age of the earth. But if I try to cover them now, this post will never be finished.

Miscellaneous Works by Thomson
References
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