A summer cooler in the days before household ACs. (Tim Carman/The Washington Post)

Here’s what Brown did write:

John Randolph, at a later day, was so fond of porter that he even drank it on the floor of the Senate, but who, save my good old friend of many years, John Hartnett, can tell us at this late day the names of the favorite drinks of a generation of statesmen who have long since passed off the stage? Mr. Hartnett was the major domo at the old Whitney House. Here he served a noble drink, a favorite with the senators and other public men who lived there, a drink made in a huge pitcher and consisting of a layer of ice, a layer of mint, a layer of sliced oranges, more ice — and then champagne poured in until the vessel was full.

I have to admit that when I read the ingredient list, my internal body temperature felt as if it had dropped 5 degrees; the drink seemed less like a cocktail lost to time than a potential act of charity from previous generations that had learned to survive D.C. summers without air conditioning.

Even though I knew George Rothwell Brown’s description lacked essential details, I wanted to honor the drink by following the “directions” precisely. I was curious to see what flavors, if any, would seep into the cocktail. I was half-expecting little more than watery champagne, given the word “muddle” never appears anywhere in that historic paragraph and the dominant ingredient is, well, ice. And lots of it.

The main element I had to play with was the champagne. I thought of buying a pricey bottle to pay homage to the cocktail that once refreshed overheated fat cats in Washington. But then I remembered I already had a bottle of Jean-Baptiste Adam Cremant d’Alsace, which the fearsome Francois Haeringer had given me almost two years ago when I profiled the chef, who, at 90 years of age, was still running L’Auberge Chez Francois with an iron fist (usually wrapped around his wooden cane). Less than a year later, Haeringer would pass away, working in the kitchen right to the very end of his life.

How better to resurrect this cocktail, I thought, than with a champagne from a man whose birth predates both the Volstead Act and Brown’s nostalgic ache for a more genteel drinking culture? Why not add an elegant taste of Alsace — courtesy of a champagne-style wine that Haeringer loved to pour — into a drink that was little more than an alcoholic fruit punch?

To my surprise, the citrus had seeped into the crisp, slightly fruity champagne, even though I had let the ingredients combine for only an hour or so. The mint flavor, as expected, was non-existent. Not even a hint of herb. I can’t say it bothered me; I skulled that cocktail like Ga­tor­ade after a sweaty run. It reminded me of San Pellegrino Aranciata.

But I also knew that in order to fairly resurrect the drink, I would need professional help. So I called Derek Brown, the author, cocktail classicist and man behind the Columbia Room. Not surprisingly, Brown had already resurrected John Hartnett’s champagne cocktail in the recent past.

The important thing to remember, Brown notes, is that 19th-century champagne tilted sweet. “Today we prefer dry champagne, but back then it was sweeter,” more demi-sec than brut, Brown says. “That’s one of the reasons why in reconstructing [Hartnett’s] old recipe... it could use a little something.”

To Brown, that little something is simple syrup for added sweetness and an orange liqueur to amp up the citrus. He, of course, also suggests a light muddle on those mint sprigs to bring out their essential oils. The mixologist says this recipe, because of its champagne base, falls squarely in the category of “cups,” not cocktails or punches.

As for a name, Brown doesn’t think twice. Hartnett, as the drink’s alleged creator, deserves the recognition. But in a splendid twist, perhaps with tongue slightly pressed against cheek, Brown riffs on the older Brown’s words — a “noble drink” — and suggests:

Hartnett’s Noble Cup

Makes 1 pitcher (4 servings)

Based on a historic recipe by bartender John Hartnett at the Whitney House in Washington; adapted by mixologist Derek Brown from the Columbia Room.

5 small mint sprigs, lightly muddled, plus 2 small sprigs (see NOTES)

Half an orange, cut into thin half-moon slices (seeded if necessary)

2 ounces simple syrup (optional; see NOTES)

2 ounces Grand Marnier (optional)

One 750-ml bottle of brut, or dry, champagne

1 cup ice cubes, plus more for serving

Place the mint sprigs at the bottom of a pitcher large enough to hold the contents of a 750-milliliter bottle of champagne. Lightly muddle the mint.

Add the orange slices, then the simple syrup and Grand Marnier, if desired. Pour the entire bottle of champagne into the pitcher. Add the ice and the 2 remaining mint sprigs, slightly tearing or bruising the leaves to release their oils). Stir briefly; refrigerate for at least 1 hour.

Serve in wineglasses half-filled with ice.

NOTES: To lightly muddle the mint, take a muddler, apply pressure to the sprigs and twist a quarter of a turn. Repeat the process no more than three times to release the herb’s essential oils. Do not over-muddle.

To make simple syrup, combine 1/2 cup of sugar and 1/2 cup of water in a small saucepan over medium heat, stirring until the sugar dissolves. Bring to a slow rolling boil, then reduce the heat to medium-low and cook for 5 minutes. Transfer to a heatproof container and let cool to room temperature.