Search Loci: Convergence:
However vast a man's spiritual resources, he is capable of but one great passion.
Discours sur les passions de l'amour. 1653.
Van Schooten's Ruler Constructions
Problem II: Given a straight line with endpoints A, B, to bisect it.
Construction: Take any point C at random away from the line AB, and from A through C draw the indefinitely long line ACD, and locate on that line CD equal to the double of AC, and from D through B make a straight line. In that line, put BE equal to BD, and, joining C, D, I say it bisects AB at F.