How can a converging lense be used to set a piece of carbon on fire

Please see the following site. You will need to scroll down the page in order to look at the pictures. Things are kind of spread out on the page.

Lenses

Thank you for the private message. You also might want to check out the information on the following site.

From Lenses To Optical Instruments

In short, yes, you should be able to, dependent on the type of carbon and the power of the light source.