If the broken cornice is a fluted one, make a zinc mould of it, using the good part of the cornice as a pattern. Remove all loose plaster, dust with a stiff brush, and well wet the cavity with water. Mix to a proper consistency a sufficient quantity of Keene's plaster, beat it up to a thick paste, and apply with a trowel and sash tool; gradually fashion the cornice by drawing the . inc mould backwards and forwards until the new portion of the cornice lines with the old. If the cornice is an ornamental one, the broken part must be made good by a casting from a mould taken from the unbroken part of the cornice.