Zygma beam

Zygma beams were a type of power source created by zygma energy for the time cabinet. Magnus Greel helped develop the idea while he was the Minister of Justice in the 51st century. It behavied like an elastic and was stretched to its fullist between the 51st century and the 1800s. (TV: The Talons of Weng-Chiang)

The Doctor compared it to a paddle ball, the paddle being the 51st century, the ball being the time cabinet and the string being the beam. The zygma beam's arrival released chronon radiation which followed Earths' telluric currents in the magnetosphere to create the Dragon Paths. (PROSE: The Shadow of Weng-Chiang)