O Caledonia

by Elspeth Barker. Harcourt Brace Jovanovich, $19.95. Ms. Barker’s juvenile heroine, born into the wrong sort of family, suffers and suffers and suffers and suffers in a decrepit castle somewhere inland from Aberdeen. She must be the most lachrymose bore since Elsie Dinsmore. The author describes Scottish weather superbly, with an unmistakable affection that seems comparable to infatuation with the neighborhood dragon.