Of the four great virgin saints (Agnes, Barbara, Katharine, and Margaret), revered with almost passionate affection in the Roman Catholic Church, each has been made the representative of an idea.   Barbara was said to be a maiden of Heliopolis, whose Christianity was revealed by her insisting that a bath-chamber should be built with three windows instead of two, in honour of the chief mystery of the Creed.  Her cruel father beheaded her with his own hands, and was immediately destroyed by thunder and lightning.  Here, of course, was symbolized the consecration of architecture and the fine arts to express religious ideas, and St. Barbara became the patroness of architects, and thence of engineers, and the protectress from thunder and its mimic, artillery.  The powder room in a French ship became known as la saint Barbe. (History of Christian Names, Yonge, 1884)