Plural of gas?

[Sailboat]

As in atmospheric gases or gasses?

US English, please.

I could swear I'm used to seeing "gasses," but I went to look it up online and I see many places and some dictionaries happily using "gases." This seems startlingly new to me.

Is this something that's in transition, or have I been reading too many British chemistry papers, or is the Web full of nitwits?

[Polycarp]

I've always seen the single -s- version in any proofread printed material.

[Machine Elf]

My wooden dictionary gives the plural as "gases." It gives the past-tense and gerund verb forms as "gassed" and "gassing", respectively.

[TheMadEngineer]

This is a case of English not conforming to its own rules, again... personally I would prefer the spelling "Gasses" be used as it does not imply in any way a hard "A" sound should be used, however "Gases" is the correct spelling.

[Shot From Guns]

Compare to bus and its plural buses. Makes you wince, but it's the official spelling.

[robcaro]

My dictionary shows "gases or gasses."

[DSYoungEsq]

Both are correct. I believe the -ss- is the older way, to conform with the need to show that the "a" is pronouced as a short vowel, but the more modern way is to simply add the -s or -es regardless of syllable quality.

[Mangetout]

Actually, never mind

[Chessic Sense]

I use "gases" as a plural noun and "gasses" as a third person singular verb.

[Balthisar]

Compare to bus and its plural buses. Makes you wince, but it's the official spelling.
As was brought up in another thread, "busses" is still acceptable, and is my preferred spelling for the same reason that "gasses" is my preferred spelling. I'm accustomed (in the welding world) to seeing both "gases" and "gasses" depending upon the nation of origin.

[Zackmo]

Both my dictionary and my chemistry textbook use the one-'s' spelling.

[Colophon]

I don't think it's a British/American issue, as the single-"s" spelling is the most common one here in the UK, too.

[Terminus Est]

The OED lists the plural as "gases" with no mention of an alternative. It gives several citations for "gases", with the earliest from 1791. There is one citation for "Gasses" from 1779, but in that case, the singular was also spelled "Gass".

[TruCelt]

Vapors