Pearlash \Pearl"ash`\, n. (Chem.)
A white amorphous or granular substance which consists
principally of potassium carbonate, and has a strong alkaline
reaction. It is obtained by lixiviating wood ashes, and
evaporating the lye, and has been an important source of
potassium compounds. It is used in making soap, glass, etc.
[1913 Webster]