Riddle

The higher I climb, the hotter I engage. I cannot escape from my crystal cage.

Choose an answer

A.Alcohol
B.Water
C.Glass
D.Mercury
Hint: It's a word with 7 letters, starting with "M".

Answer

Mercury

Why this is the answer

As in the earlier thermometer riddle in this set, this describes mercury inside a glass ("crystal") tube, rising higher as the temperature increases -- the two riddles share almost identical wording and the same answer.

This riddle is filed under Hard/Difficult Riddles and rated Medium.