What is "fuming liquor of libavius"

Stannic \Stan"nic\ (-n[i^]k), a. [L. stannum tin: cf. F. stannique.] (Chem.) Of or pertaining to tin; derived from or containing tin; specifically, designating those compounds in which the element has a higher valence as contrasted with stannous compounds. Stannic acid.

1. A hypothetical substance, Sn(OH)4, analogous to silicic acid, and called also normal stannic acid.

2. Metastannic acid.

   Stannic chloride, a thin, colorless, fuming liquid, SnCl4, used as a mordant in calico printing and dyeing; -- formerly called spirit of tin, or fuming liquor of Libavius.

   Stannic oxide, tin oxide, SnO2, produced artificially as a white amorphous powder, and occurring naturally in the mineral cassiterite. It is used in the manufacture of white enamels, and, under the name of putty powder, for polishing glass, etc.