Substitute for oil using butter

I went to make corn bread and realized I didn't have any oil. I googled "substitute oil using butter" and found this answer at wiki.answers.com:

Butter is 80% fat, oil is 100% to keep volume of fat the same, use 125% (5/4) the amount of butter vs. oil.

Then use 80% of the amount of liquid ( because you are using 5/4 as much butter as oil, so you need 4/5 of the liquid to compensate).

Example: ¾ cup oil is 6 oz. 125% of 6 oz is 7.5 oz of butter, which is 2 sticks -1 TBS (15 TBS)

Subtract 3 tablespoons of milk, or whatever liquid is called for.

Original answer probably gives a good result, but doesn't have the equivalent amount of liquid as the originalrecipe:

When substituting butter or oleo for oil in a recipe, generally add 1 1/4 cup butter per cup of oil.
You are basically substituting enough butter (when melted) to equal the same amount of liquid in the recipe.

I also found lots of recommendations of using applesauce.