I keep having to make apologies for myself - I am not a chemist, nor a chemistry student, I am self taught. But my guess would be that what you say about Ammonium hydroxide seems logical, however I would be more inclined to simply call it liquified ammonia gas which will be alkali and corrosive and damaging to tissues, not the ones you sneeze with! The ammonia that is in liquid form is not ammonium hydroxide, now this is what I read many times months ago and there was a good reason for this, but please somebody else answer this since my knowledge is sparingly amateur over this. However in the meantime I will try and look it up.
A quick searcgh just found these references, but I can not explain further, sorry.
It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests a base with composition [NH4+][OH−], it is actually impossible to isolate samples of NH4OH, as these ions do not comprise a significant fraction of the total amount of ammonia except in extremely dilute solutions. Wikpedia.
Ammonium hydroxide (NH4OH) is a common, though not entirely correct name for a solution of ammonia dissolved in water.
when dissolved in water ammonia reacts to a small degree with water to produce ammonium hydroxide (NH3 + H2O --> NH4OH). But this only forms in a small amount and most of the ammonia remains unreacted. This substance cannot be isolated as any attempt to separate it out will result in it reverting back to ammonia and water. http://wiki.answers.com
So it appears that my original thinking was correct, that it is simply ammonia gas locked up with water molecules and then that sinks to the ground.