In 1794 Joseph Priestley fled England and the church-and-king sentiment that had set ablaze his Birmingham house and laboratory in 1791. His flight to America was noted by the United Irishmen with a public letter. This most radical group in the entire camp of English sympathizers with the French Revolution not only lamented English repression but also offered a marvelous hymn to the tripartite linkage of America, useful science, and radical change.The Emigration of Dr. Priestley will form a striking historical fact, by which alone future ages will learn to estimate truly the temper of the present times. … But be cheerful, dear Sir, you are going to a happier world, the world of Washington and Franklin. In idea we accompany you.… We also look to the new age when man shall become more precious than fine gold, and when his ambition shall be to subdue the elements, not to subjugate his fellow creatures, to make fire, water, earth, and air obey his bidding, but to leave the pure ethereal mind, as the sole thing in nature free and invincible…. The attention of a whole scientific people [here] is bent to multiplying the means and instruments of destruction … but you are going to a country where science is turned to better use.The relationship between science and progressive politics was by no means one-way. Just as science would ameliorate the human condition, so a progressive politics would encourage scientific advances.