Wow. 1/10,000 deg F sensitivity. :-)
http://www.globalwarmingsolutions.co.uk/joules_sketch_of_thermoscope_and_references.htm
This describes J. P. Joule's thermoscope.
Joule was genius in many ways, not least of which was in designing elegant, simple and incredibly accurate and precise instruments. With some of his calorimeters and thermometers, he could have easily have measured the excess heat from cold fusion experiments. This is why it is so absurd that many skeptics today question modern calorimetry. Martin Fleischmann points out that the instruments he uses were developed by Joule. The only difference is that temperature and power are recorded automatically by a computer instead of manually in a notebook.
Many other 19th-century instruments that achieved wonderful precision that would be a big challenge even today. William Thompson, the guy Joule was writing to in this letter (I assume), developed the mirror galvanometer for the transatlantic cable. After the second table was laid, the two cables were temporarily spliced together in Newfoundland for an experiment. The mirror galvanometer could detect a signal sent from Ireland to Newfoundland and back, over 4000 miles, which was generated with a battery made from a "lady's silver thimble containing a few drops of acid."
- Jed
