Cook 60 to 90 minutes, turning once or twice and checking occasionally to make sure the liquid is bubbling slowly; adjust heat accordingly.

The professor was pointing to one of the tanks at the side of the cabinet; Marquette observed that its liquid had bubbled.

Flowing through tubes and flasks, colored liquids bubbled and oozed.

The mobile liquid swirled and bubbled, twisting in vortices.

Regulate heat, if needed, so the liquid is just gently bubbling.

The liquid swirled and bubbled.

Around a few, tiny salamanders danced, and within the vessels liquids bubbled.

Dark liquid frothed and bubbled in the cups as if troubled by internal fire.

A few minutes passed, while liquids bubbled and gases of vivid colors ran through the glass coils.

It looked like a suit of battle armor except for some external tubes through which liquids bubbled.