Johnston
The letters of the London Underground: an early, clear sans serif.
Edward Johnston was a calligrapher, and the Underground's manager Frank Pick asked him to draw a typeface that would be easy to read and look modern. It appeared in 1916.
The typeface has been used by London's public transport ever since, in updated versions. It later influenced Gill Sans and other British sans serifs.
Materials: Originally wooden type and enamel signs
Manufacture: Drawn for signs and posters, long before it existed as a typeface for setting.
The o as a perfect circle.
The dot on the i in the shape of a diamond.
Proportions from the classical Roman capitals.