Not a cake to bake Barring nuclear fusion, which eludes the efforts of science to harness it, the most powerful source of calorific energy so far discovered has been the Pop-Tart caught in the toaster. Einstein, had he known about the Pop-Tart (to him, as unsuspected as the Higgs boson), might have reformulated his equation as E=pc², where p is one Pop-Tart unit. But now firemen in Liverpool have found an even more powerful energy source: Eccles cakes. In recent days, three fires on Merseyside have started through an Eccles cake being put in a microwave to warm up. Apart from an Eccles cake not needing to be warmed up (its curranty interior, like a flies" graveyard, being best left at ambient temperature), microwaving one is madness. It might melt down all the way to the Earth's core. Yet if scientists could tame this stupendous energy, we might bid wind turbines a glad goodbye.