Highly rare handwritten, signed note in black fountain pen, given at the top of a pre-printed statement of thanks for letters of congratulation on the Jubilee of his professorship.  He writes: "Dear Rucher, This is for yourself.  I am sending to Sir Douglas an expression of my thanks to the Council for the Address which you brought me from the British Association.  Yours, Kelvin."  In fine condition, with two light mailing folds. Eminent Belfast-born mathematician, physicist and engineer William Thomson, 1st Baron Kelvin, is remembered for his groundbreaking work in the mathematical analysis of electricity and he formulation of the second law of thermodynamics. The first British scientist to be elevated to the House of Lords, absolute temperatures are stated in units of kelvin in his honor. While the existence of a coldest possible temperature, termed "absolute zero," was recognized prior to his work, Kelvin is known for determining its correct value as approximately −273.15 degrees Celsius or −459.67 degrees Farenheit.  The Joule-Thomson effect is also bears his name.

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