E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
To roar like Tregeaglevery loudly. Tregeagle is the giant of Dosmary Pool, on Bodmin Downs (Cornwall), whose allotted task is to bale out the water with a limpet-shell. When the wintry blast howls over the downs, the people say it is the giant roaring. (See GIANTS.)