El Bar Americano en España by Pedro Chicote (1927, p.81)

1 small spoonCuraçao — Curaçaobase
Seltzer water — Cold seltzer waterdilution
1 copitaFrench vermouth modifier
  1. Build in a vermouth glass with curaçao and French vermouth.
  2. Fill with very cold seltzer water and serve.

Chicote notes vermouth also combines well with orange bitters, Angostura bitters, or Secrestat bitters.