Assuming experiments in the 1770s had proven phlogiston theory correct instead of invalidating it, what would the implications be for the development of science and technology from then on? What kind of world would be created using phlogiston and technologies derived from it? How would phlogiston physics/chemistry operate, and how would it affect other areas of scientific study?
I feel like phlogiston rayguns and other popular cliches are a bit over the top, but perhaps we would see revolutions in phlogiston as an abundant source of fuel or a potent lifting medium (given some later additions to the theory claiming that phlogiston had “negative mass” or imparted some ethereal quality of “lightness” to objects)? Could steampunk-style phlogiston airships become commonplace and start the Aviation Age, complete with its devastating wars and irrevocably altered shipping industry, a hundred or so years early?