Iamtaller you are soooo wrong
1. saltwater freezes on different temperatures due to different concentrations of Salt (for example Seawater at about -2°C or 28°F) so you can't mark this as a fixed point and that isn't the Fixing point for the Fahrenheit scale.
I quote the fixing points from here:
http://en.wikipedia.org/wiki/Fahrenheit (read the first column fully....)
and you can look up the freezing points of different Saltwater(Brine) Concetrations here :
http://en.wikipedia.org/wiki/Brine2. 10=2*5 and 12=2*2*3 so both have 2 prime divisors which gives both an equal probability do produce a periodic result when divided by a random number (I'd be willing to give you a full mathematical prove for that if you want since I can't find a good googlebookslink with it its called the "Satz von Steiner"....)
so in that aspect both are equally good base Numbers.
However the arguments for 10 as a base are obvious....
---Captain mode off-----