Glass

Sometimes you run across outmoded ingredients in drink recipes; sometimes the units of measurement themselves are outmoded or obscure. Case in point: the designation "glass" in the Cablegram post. In this case I think it's safe to assume that Duffy means a glass used to serve whiskey, or a shot glass; a shot glass could hold 1, 1 1/4 or 1 1/2 ounces (the 1 1/2 ounce glass is also called a "jigger"). Legally, a "shot" is one ounce. I sometimes interpret "glass" as one ounce in this context, if 1 1/2 ounces seems like too much. Taste should be the guide in interpreting any drink recipe.

"Drink" is another indefinite amount that appears in many old recipes. Since it's used mainly with spirits, I apply the "glass" rule: the actual amount is in the neighborhood of 1 1/2 to 1 ounce, depending on preference.

I've used this online dictionary of measurement units before. Its scope is broad, so you may not find a lot that refers to bartending specifically, but it has helped me in the past.