and pricking their points into a Board so that their edges might look
towards one another, and meeting near their points contain a rectilinear
Angle, I fasten'd their Handles together with Pitch to make this Angle
invariable. The distance of the edges of the Knives from one another at
the distance of four Inches from the angular Point, where the edges of
the Knives met, was the eighth part of an Inch; and therefore the Angle