 The punch-cutters he worked on were, essentially, pantographs that could engrave copies of given shapes (the outlines of letters or characters) as three-dimensional objects at a much smaller scale (the punches used to shape each letter in hot metal typesetting).Between 1900 and 1902, with Linotype managers Arthur Pollen and William Henry Lock, Barr also designed pantographs operating on a very different scale, calculating aim for naval artillery based on the positions, headings, and speeds of the firing ship and its target.Barr was a friend of William Schooling, and worked with him in exploiting the properties of the golden ratio to develop arithmetic algorithms suitable for mechanical calculators.