Abstract This is a realization of an instrument designed rudimentarily in the author’s communication to the Royal Society (“ Proceedings, February 3rd, 1876), entitled “ On an Instrument for Calculating (∫ϕ(x)Ψ(x)dx), the Integral of the Product of two given Functions.” It consists of five disk globe and cylinder integrators of the kind described in Professor James Thomson’s paper “ On an Integrating Machine having a new Kinematic Principle,” of the same date, and represented in the annexed woodcuts. The five disks are all in one plane, and their centres in one line. The axes of the cylinders are all in a line parallel to it. The diameters of the five cylinders are all equal, so are those of the globes; hence the centres of. the globes are in a line parallel to the line of the centres of the disks, and to the line of the axes of the cylinders.