1763 is the temperature that silver melts. Molten silver can be poured into moulds and formed into castings or ingots. At 1763 degrees silver changes from a solid to liquid, from something relatively hard to something that can flow.
1763 is also a somewhat relevant year. As his silversmithing sales lagged, Paul Revere turned to engraving, drawing cartoons, and even dentistry (one can still hear him on his fateful ride upon seeing the British troops movements screaming, “the fillings are coming”). In 1763 alarmed by the actions of the British empire, Paul began to organize other artisan and craftsmen to protest parliament and the crown. Later, he would further venture into politics and engrave the famous depiction of the Boston Massacre.
Artists and art have always had a role on influencing political movements. Art, by its very nature, challenges the status quo by allowing free subjective expression. To the extent that this is true, all art is therefore potentially political in nature.