Chill a coupe glass.
Combine the gin, dry vermouth, sweet vermouth, triple sec and lemon juice in a shaker.
Add two dashes of Angostura bitters.
Add ice and shake briefly, 8–10 seconds.
Fine-strain into the chilled coupe and express a lemon twist over the surface.
Another Savoy entry from 1930. It is a "perfect" cocktail in the technical sense, meaning it splits the vermouth between sweet and dry, and the tiny measures of Cointreau and lemon are seasoning rather than ingredients. Under-measure them and you have a Bronx; over-measure and you have a mess.
My Bar Shelf reads your shelf and shows you every cocktail you can make from what you already own, including Journalist.