Daly's Bartenders' Encyclopedia by Tim Daly (1903, p.77)

2 dashesAbsinthe base
0.5 glassice — fine icebase
1 wine glassPlymouth gin base
1 dashAngostura bitters bitter
1Olive garnish
1 dashgum syrup — Source says one or two dashes.sweetener
  1. Half fill a mixing glass with fine ice and add the gum syrup, Angostura bitters, Plymouth gin, and absinthe.
  2. Spoon well, strain into a cocktail glass, put in an olive, and serve.

Garnish: Olive.

Ice: Fine ice

This is a useful prewar olive-garnished gin aromatic checkpoint distinct from Martini or Imperial service.

The olive garnish is structurally important, not merely decorative.

See also: Imperial Cocktail, Martini Cocktail