Jack's Manual by J. A. Grohusko (1910, p.53)

0.5 limelime juice — Squeeze half a lime in the glass.acid
1 portiongin — Source gives 100% gin.base
1 pieceice base
ginger ale — Fill glass with ginger ale.dilution
  1. Build the ice, lime juice, and gin in a highball glass.
  2. Fill with ginger ale, stir, and serve.

Ice: Ice

See also: Gin Rickey, Dunham Cooler