Dervishes, a name given to members of certain mendicant orders connected with the Mohammedan faith in the East. Of these there are various classes, under different regulations, and wearing distinctive costumes, with their special observances of devotion, and all presumed to lead an austere life, some of whom live in monasteries, and others go wandering about, some of them showing their religious fervour in excited whirling dances, and others in howlings; all are religious fanatics in their way, and held sacred by the Moslems.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Derg, Lough * Derwentwater