If you with your present technical knowledge of the modern world would suddenly be transported back to the year 1800, how will you get rich?

I’d go in as a hospital consultant. I’d explain germ theory and prove how sterilizing equipment and washing hands and such is good for keeping people healthy. I’d go as a civic planner, explaining how to keep sewage from the drinking water, and that filtering water with charcoal and then boiling can help provide clean fresh water to people. Those two things alone should help society drastically. Then I can sit down and really think about things. Like as a civic planner I could let them know about how the future will expand cities, and how to set up roads and public transport early to be expandable and useful to a much higher population load.