What is "chile saltpeter"

Niter \Ni"ter\, Nitre \Ni"tre\, n. [F. nitre, L. nitrum native soda, natron, Gr. ?; cf. Ar. nit[=u]n, natr[=u]n natron. Cf. Natron.]

1. (Chem.) A white crystalline semitransparent salt; potassium nitrate; saltpeter. See Saltpeter.

2. (Chem.) Native sodium carbonate; natron. [Obs.]

   For though thou wash thee with niter, and take thee much soap, yet thine iniquity is marked before me.
   --Jer. ii. 22.

   Cubic niter, a deliquescent salt, sodium nitrate, found as a native incrustation, like niter, in Peru and Chile, whence it is known also as Chile saltpeter.

   Niter bush (Bot.), a genus ( Nitraria) of thorny shrubs bearing edible berries, and growing in the saline plains of Asia and Northern Africa.