The House on the Marsh by Florence Warden

It was the elfish baby-girl Mona who first put me on the track of the solution of the mystery about Mr. Rayner's room. This ill-cared-for little creature, instead of resenting the neglect she suffered, prized the liberties she enjoyed of roaming about withersoever she pleased, and sitting in the flower-beds, and in the mud at the edge of the pond, and making herself altogether the very dirtiest little girl I had ever seen, and objected vehemently to the least attempt at judicious restraint. The little notice she got was neither consistent nor kind. Sarah or Jane would snatch her up, regardless of her shrieks, to shut her up in an empty bedroom, if she showed her grimy little face and tattered pinafore anywhere near the house in the afternoon, when callers might come. But, if they did not see her, they forgot her, and left her to talk and croon to herself, and to collect piles of snails, and to such other simple occupations in her favorite haunts until tea-time, when she generally grew hungry of her own accord, and, returning to the house, made an entrance where she could.

The day after the violin-playing was very wet, and, looking out of the window during lessons with Haidee, I caught sight of her small sister trotting along composedly without a hat in the fast-falling rain. I jumped up and called to her; but she took no notice; so I ran to fetch my umbrella and set off in pursuit. After a little search, I saw her steadily toddling up a side-path among the trees which led to the stables; and I followed softly without calling her again, as, if irritated by pursuit, she might, I knew, plunge among the trees and surrender only when we were both wet through.