Harvard University's Putnam Gallery has a collection of historical scientific instruments. Pictured above is Benjamin Martin's cometarium, which dates back to about 1766. Here's what it did:
This apparatus was designed to demonstrate how the speed of a comet varies in its orbit according to Kepler's law of equal areas. The comet Benjamin Martin chose for this instrument is Halley's Comet, which goes around the Sun every 75 1/2 years. Martin began producing cometaria before Halley's Comet made its predicted return, and so was betting that Halley would prove correct in his theory.
http://dssmhi1.fas.harvard.edu/emuseumdev/code/emuseum.asp?collection=120&collectionname=CHSI%27s%20Putnam%20Gallery&style=single¤trecord=67&page=collection&profile=objects&searchdesc=CHSI%27s%20Putnam%20Gallery&sessionid=C2E2B76B-E06A-4F9D-8DD1-8AECE2978F18&action=collection¤trecord=68 via CrunchGear | Photo: Harvard University