drown the miller: to add too much water to flour when cooking. Used metaphorically in story.
fossick: pick over areas for gold. Not mining as such.
half-caser: Two shillings and sixpence. As a coin, a half-crown.
half-sov.: a coin worth half a pound (sovereign)
Gladesville: Sydney suburb, where the mental hospital used to be
goanna: various kinds of monitor lizards. Can be quite a size.
Homebush: Saleyard, market area in Sydney
humpy: originally an aboriginal shelter (=gunyah); extended to a settler’s hut
jackaroo: (Jack + kangaroo; sometimes jackeroo)—someone, in early days a new immigrant from England, learning to work on a sheep/cattle station (U.S. “ranch”)
jumbuck: a sheep (best known from Waltzing Matilda: “where’s that jolly jumbuck, you’ve got in your tucker bag”.