Cups In Pies. The cup which is placed upside down in meat and fruit pies is only tilled with air when it is put into the pie. When the heat of the oven begins to act this air expands, and forces its way under the edge of the cup at the bottom of the pie. In this action it produces a somewhat similar effect to stirring with a spoon. When the whole substance of the pie has attained the boiling heat, the air in the cup expands no more ; or the contrary, as soon as the pie is removed from the heat, the air in its interior begins to contract, and the pressure of the atmosphere without drives the gravy into the cup. It is a mistake to suppose that the cup prevents the syrup or | gravy boiling over while the dish is in the oven ; but it is useful in many ways. - to support the crust, etc.