I thought Octane (if as in methane, propane, etc...) refers to the number 
of carbons in the molecule *(Oct- = 8)*  The -ane suffix refers to the 
type of bonding between adjacent carbons (single bond) Par l'example octene
would mean at least one double bond (-ene suffix).  I was wondering what
the rating of gas in terms of octane (i.e. 87, 89 etc) refers to.  Is this 
related to some percent (or proof) of octane in the gas?

christian