Portuguese
hidróxido de cálcio Catalan
hidròxid de calci 
A caustic substance produced by heating limestone.
1
Acted upon by water it is at once decomposed, yielding acetylene and calcium hydrate.
2
By tipping the tube the amount of calcium hydrate required can be poured into the generator.
3
Such a process of purification is to be seen in the addition of alum, sulphate of iron, and calcium hydrate to water.