Edgeworth put a powder and a transparent liquid into a clear glass beaker, then heated it over an alcohol lamp.
After a while, he removed the beaker from the lamp and poured its contents onto a silver tray. It remained liquid. Then he touched the liquid in the tray with a finger, and it froze at an astonishing speed.
Next, Edgeworth poured out the rest of the liquid in the beaker. It froze into an icicle, and applause immediately broke out around them.
"What is the principle behind that?" a lady in the salon asked.
"If you do not understand science, magic is everywhere in the world." Saint-Hilaire, who had gone to Egypt with Napoleon, said to Georgiana, "Do you know how he did it?"
Georgiana leaned closer and sniffed carefully.
"Vinegar and baking soda," she answered, having seen Edgeworth ask the bartender for some.
"And what else?" Saint-Hilaire continued.
She was not sure whether people in this era knew about supersaturated solutions. The earlier silver tray had been left outside to chill for some time. The sodium acetate solution, already unstable due to supersaturation, had become even more unstable after cooling rapidly. At that point, a light touch was enough to cause sodium acetate to precipitate. It looked as though it had frozen, but the substance that resembled ice crystals was actually sodium acetate.
"Things are often not what they appear to be," Georgiana said. "That is not real ice."
Saint-Hilaire smiled.
"If you put it that way, how are we supposed to continue our conversation?"
She froze for a moment.
"You can pretend not to know, and then I can explain the principle to you, even if you already know it."
"That would just be talking nonsense." She took a sip of wine.
Saint-Hilaire could not continue, and