Curling tongues are a modern invention, developed as a convenience to curl hair in a professional way by the novice at home.
To give a section of hair a curl, it is first trapped with a lift up tongue which runs the length of a heating tube. The hair is then rolled onto the heating tube and held in position for a few seconds. The heat from the heating tube will give the section of hair a semi-permanent wave within seconds.
The heating tube contains an electrical element, this is a long coiled wire fed up and down the tube to give an even dissipation of heat.
In the mid 80's, gas powered curling tongues started to appear. These utilise a small butane canister stored in the handle to provide the heat to the heating tube. Because this type requires no electrical connection they offer the convenience of a `go anywhere' cordless appliance.
