As he struggled to figure out how to get help, Schab decided to get rid of the pills — and as soon as he dumped them in the toilet, they “started to effervesce like an Alka-Seltzer.”

Fernandez is a true opera singer, from Philadelphia, who effervesces with wonder and benign hauteur.

DiDonato’s vibrato, which oscillates so quickly it seems to effervesce, is built for highly ornamented Baroque melodies.

The waters effervesced like the 1920s themselves, but the solemn weight of the Depression evidently closed its doors.

Ms. Diefenbach, who was already equipped with a pilot’s license, was sent to the effervescing volcano with a handful of keen colleagues and a small fleet of flying robots.