The Old Waldorf-Astoria Bar Book by Albert Stevens Crockett (1935, p.43)

2 dashesorange bitters base
0.5 partWhiskey base
0.5 partdry vermouth — French vermouthmodifier
  1. Build the orange bitters, French vermouth, and whiskey over ice.
  2. Serve in a cocktail glass.

See also: Brut