Adriaan Vlacq (1600–1667) was a Dutch publisher and bookseller. He translated and published the works of John Napier and Henry Briggs in Dutch. But he also extended and refined the logarithm tables of Briggs, bringing the log values to ten decimal places, and published these results in 1628. The title page of the French edition, *Arithmetique* *Logarithmetiqu*e, also released in 1628, is shown here. Vlacq’s logarithmic tables were the most accurate ones in existence for many years.

Here on pages 142 and 143, we find the beginnings of Chapter XVI of the *Arithmetique*. Here, Vlacq discussed the use of logarithms in the solution of trigonometric problems. He considered the situation where, given the sides of a triangle, one seeks further information; namely, the altitude, the diameters of inscribed and circumscribed circles, and the angles of the triangle.

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