Mark Barr

James Mark McGinnis Barr[1] (18 May 1871 – 15 December 1950)[2][3][4] was an electrical engineer, physicist, inventor, and polymath known for proposing the standard notation for the golden ratio.

[9] Hamlin Garland writes that, "after thirty years in London", Barr returned to America "in order that his young sons might become citizens".

[9][11] Whitehead, in subsequent letters to his son North in 1924 and 1925, writes of Barr's struggles to sell the design for one of his calculating machines to an unnamed large American company.

[4] At Linotype, Barr improved punch-cutting machines by substituting ball bearings for oil lubrication to achieve a more precise fit, and using tractrix-shaped sleeves to distribute wear uniformly.

[13] 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.

[14] 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.

Cook wrote that Barr chose Φ by analogy to the use of π for the ratio of a circle's circumference to its diameter, and because it is the first Greek letter in the name of the ancient sculptor Phidias.

However, after much effort in relocating the bacterium after exhausting the original supply (a barrel of vinegar from New Jersey), the process ended up being less cost-effective than natural rubber, and the business failed.