Be forewarned, this week's candidate is obscure....!
I was an English clergyman, instrument-maker, and biblical "exegete."
I was a founding member of the Royal Society.
I invented "a paire of beame Compasses," accurate enough to divide an inch into a hundred or a thousand parts.
I constructed a sundial used at Trinity College, plus designed an instrument for drawing in perspective (though Christopher Wren got credit for its invention).
I must admit to having an understanding of only "common Arithmetique, and never went farther in Geometrie then the first six bookes of Euclid."
BUT...I wrote one of the most curious, fascinating of books of the 17th century, entitled An Interpretation of the Number 666, which shows all the numerical manifestations of the number 25, the approximate square root of Devil's Number "666" as connected to the Catholic Church (Note: The book recently sold on ebay for more than $1000).