My interpretation:
1.5 oz Dubonnet
0.5 oz The Famous Grouse
Stir with broken ice, strain into cocktail glass, serve. — This cocktail, nowadays known as a Rob Roy (esp. with bitters and a cherry), first appears under this name in JM 1910s (Third Edition). The bitters and cherry and not necessary. There is a Hamilton in the Lowlands of Scotland, which leads us to conclude that perhaps a Scotch of that area, such as Auchentoshan, might be most appropriate.
