Colin Maclaurin’s *Treatise of Algebra* was published posthumously in 1748, two years after his death. This is the title page of the sixth edition (1796).

Here in Chapter 13, page 85, Maclaurin began a discussion of the solution of a quadratic equation that follows through pages 86 and 87.

*These images from its George Arthur Plimpton Collection are presented through the courtesy of the Columbia University Libraries.*