(5) "Gas" means all natural gas, including casing-head gas, and all other hydrocarbons not defined as oil in paragraph (10) of this Code section.

(1) "Gas" means natural gas or manufactured gas, or a combination of both.

(8) "Gas" means either natural or synthetic gas, including propane, manufactured, methane from coal beds, geothermal gas, or any mixture thereof, whether in gaseous or liquid form, or any byproduct resulting therefrom.