1. Although this word is not directly related to this sal or salt unit, it is presented here because of its relationship to "salt".
2. A colorless gas that is about one half as dense as air at ordinary temperatures and pressures.

It has a characteristic pungent, penetrating odor and it forms a minute proportion of the atmosphere.

It is found in volcanic gases and as a product of decomposition of animal and vegetable matter.

Because ammonia was at one time developed with the destructive distillation of the horns and hooves of animals, its water solution was called "spirits of hartshorn". Ammonia has also been called "alkaline air" and "volatile alkali".

3. Etymology: the name ammonia is directly related to Amon, or Amen, the Egyptian god of life and reproduction and identified by the Romans with Jupiter.

Deposits of ammonium chloride were found near the temple of Amon in Libya which were named sal ammoniac, "salt of Amon".

The gas known as nitrogen hydride comes from sal ammoniac; and in 1782, the Swedish chemist, Torbern Bergman, presented the term ammonia for this gas.