Robert Hunt, in his _Popular Romances of the West of England_, divided the fairies of Cornish folk-lore into five classes: (1) the Small People; (2) the Spriggans; (3) the Piskies; (4) the Buccas, Bockles, or Knockers; (5) the Brownies. This is an incorrect classification. The _Pobel Vean_ or Small People, the Spriggans, and the Piskies are not really distinguishable from one another. Bucca, who properly is but one, is a deity not a fairy, and it is said that at Newlyn, the great seat of his worship, offerings of fish are still left on the beach for him. His name is the Welsh _pwca_, which is probably 'Puck', though Shakespeare's Puck was just a pisky, and it may be connected with the general Slavonic word _Bog_, God; so that if, as some say, _buccaboo_ is really meant for _Bucca-du_, Black Bucca, this may be an equivalent of _Czernobog_, the Black God, who was the Ahriman of Slavonic dualism, and _Bucca-widn_ (White Bucca), which is rarer, though the expression does come into a St. Levan story, may be the corresponding _Bielobog_. _Bockle_, which personally I have never heard used, suggests the Scottish _bogle_, and both may be diminutives of _bucca_, _bog_, _bogie_, or _bug_, the last in the sense in which one English version translates the _timor nocturnus_ of Psalm XC. 5, not in that of _cimex lectularius_. But _bockle_ and _brownie_ are probably both foreign importations borrowed from books, though a 'brownie' _eo nomine_ has been reported from Sennen within the last twenty years. The Knockers or Knackers are mine-spirits, quite unconnected with Bucca or bogles. The story, as I have always heard it, is that they are the spirits of Jews who were sent by the Romans to work in the tin mines, some say for being concerned in the Crucifixion of our Lord, which sounds improbable. They are benevolent spirits, and warn miners of danger.