Emily Dickinson Lexicon

CALX, n. [plur. calxes or calces. L. calx; Sax. cealc, a stone, calculus, and chalk; D. kalk; G. kalk; Sw. kalck; Dan. kalk; Fr. chaux. The same word signifies chalk, lime, mortar, and the heel, and from that is formed calculus, a little stone. The word then signifies primarily, a lump, or clod, or hard mass, and is allied to callus. If calx is from χαλιξ, the usual orthography was not observed by the Latins. See Calculate.]

Properly lime or chalk; but more appropriately, the substance of a metal or mineral which remains after being subjected to violent heat, burning, or calcination, solution by acids, or detonation by niter, and which is or may be reduced to a fine powder. Metallic calxes are now called oxyds. They are heavier than the metal from which they are produced, being combined with oxygen. – Coxe. Encyc. Calx nativa, native calx, a kind of marly earth, of a dead whitish color, which, in water bubbles or hisses and without burning will make a cement, like lime or gypsum. Calx viva, quick lime, is lime not slaked.