Biblical nitre was probably natron, a naturally occurring soda or alkaline substance, rather than modern saltpetre. It was used for cleansing and reacts strongly with vinegar.
Definition
Nisroch was an Assyrian deity whose temple was the place where Sennacherib was killed by his sons.
Biblical Usage
Nisroch appears in the account of Sennacherib’s assassination after the king had gone into the temple of his god to worship.
Historical Background
The identity of Nisroch is uncertain. It has been connected with an eagle-headed figure on Assyrian monuments and, by some, with Asshur, the national deity.
Historical Bible Dictionaries
Easton's Bible Dictionary
Probably connected with the Hebrew word nesher, an eagle. An Assyrian god, supposed to be that represented with the head of an eagle. Sennacherib was killed in the temple of this idol (2 Kings 19:37; Isa. 37:38).
Smith's Bible Dictionary
(the great eagle) an idol of Nineveh, in whose temple Sennacherib was worshipping when assassinated by his sons, Adrammelech and Shizrezer. (2 Kings 19:37; Isaiah 37:38) This idol is identified with the eagle-headed human figure, which is one of the most prominent on the earliest Assyrian monuments, and is always represented as contending with and conquering the lion or the bull.
International Standard Bible Encyclopedia (ISBE)
<p>nis'-rok, niz'-rok (nicrokh): The Assyrian god in whose temple Sennacherib was worshipping when put to death by his sons (2Ki 19:37; Isa 37:38). The name is not found elsewhere. Some identify him with Asshur, the national deity.</p><p>See BABYLONIA AND ASSYRIA, RELIGION OF.</p>