0 degrees Fahrenheit was set to be colder than the coldest temperature you're likely to find in Denmark. The ammonium chloride mixture was worked out later to make it sound a little more sciency.
http://www.straightdope.com/columns/read/3146/did- cecil-err-in-explaining-the-significance-of-zero-f ahrenheit [straightdope.com]
(Score: 1) by SleazyRidr on Tuesday March 18 2014, @12:01PM
0 degrees Fahrenheit was set to be colder than the coldest temperature you're likely to find in Denmark. The ammonium chloride mixture was worked out later to make it sound a little more sciency.
http://www.straightdope.com/columns/read/3146/did- cecil-err-in-explaining-the-significance-of-zero-f ahrenheit [straightdope.com]