Sentence:  <small>The Witch, with much ceremony, fills the basin. As FAUST is about to raise it to his lips, it emits a clear flame.</small> /  MEPHISTOPHELES. Quick! quickly down with it!—no breathing time allowed! "[…]" And does a <WSD>lambent</WSD> flame prevent thee quaff? 
Meaning of the word marked with <WSD> tags:  Glowing or luminous, but lacking heat.