The original recipe calls for "One bottle imported Ginger Ale". I'm curious if they used to come in bottles of about 90 ml / 3 oz, or if they were just originally using a lot more Ginger Ale. (A quick Google seems to suggest that 7 oz was the smallest.)
The coalescence of flavors works so well in this drink. A great introduction to scotch, and a lot more approachable than the equally good scotch highball.
I’ve loved this cocktail ever since I found it in Ted Haigh’s Vintage Spirits and Forgotten Cocktails. To me, the lime essential. Trying to revive it by converting the many Moscow Mule drinkers out there…it is SO much more interesting!