Aunt Jane's Nieces on Vacation by BAUM, L. Frank

Aunt Janes Nieces on Vacation is a juvenile novel for girls, written by L. Frank Baum. It is the seventh in the ten volumes in the Aunt Janes Nieces series, and carries forward the continuing story of the three cousins Lousie Merrick Weldon, Patsy Doyle, and Elizabeth De Graf. Like all the books in the series, it was issued under Baums Edith Van Dyne pseudonym. (Summary adapted from Wikipedia)