Daly's Bartenders' Encyclopedia by Tim Daly (1903, p.97)

2 dasheslemon juice acid
1 wine glassbrandy base
1 pony glassSt. Croix rum base
0.5 teaspoonfulsugar — Dissolved in a little seltzer.base
0.5 glassice — fine iceother
3 dashesRaspberry syrup — Add after straining and stir up with a spoon.sweetener
  1. Dissolve the sugar in a little seltzer and add the lemon juice, St. Croix rum, brandy, and fine ice.
  2. Spoon well, strain into a sour glass, add the raspberry syrup, stir up with a spoon, and serve.

Ice: Fine ice

Daly's warning about its real strength under a delicate taste is a useful period framing detail.

The post-strain raspberry-syrup addition is the defining move here.

See also: Fancy Brandy Sour, St. Croix Sour