Explanatory notes
… peroxide (“dioxide”), sodium cyanide, sodamide, etc., the indigo industry, the manufacture of explosives (chemical … metal (specific gravity 1.57), used in the purification of argon, the refining of copper or steel, the manufacture of … the amalgams of heading 28.43 or 28.53. It is used in gold or silver metallurgy, in the gold‑ or silver‑plating …