Ventilation demands extreme care. “The position of the milk-room with relation to the other rooms of the dairy, as the churning and the cheese-room, and the scalding or washing-room, should be such that air can be admitted on three sides of the room, so as to ensure an equable supply of air all over the interior of the milk-room. The means adopted for ensuring a supply of fresh air by the windows are of very simple character, namely, making each window in halves, the lower and upper halves being hinged to a bar stretching horizontally across the centre of the window frame; the lower half being hinged so that it opens inwards and upwards, the upper half inwards and downwards. By adjusting the opening of the two halves, the fresh air may be admitted in any required volume, and in any direction--upwards towards the ceiling, and downwards towards the floor. For removing the used air, there are many plans. One good suggestion is that the ceiling be made up of narrow fillets so placed that spaces are left throughout the whole surface of ceiling; through these spaces the air passes, into the space between the inner ceiling and the outer roof, in which are placed ventilators with valves, which may be opened and closed as desired. If a ceiling be dispensed with and an open roof adopted, the roof will require to be double, that is, a hollow space between the inner and outer boarding; this will tend to keep the temperature of the dairy more equable, than if the boarding and slates are the only covering. The double roof is simply made by lining the inner side of rafters with inch boarding tongued and grooved. The inner surface of boarding will be all the better if papered with a glazed white paper. The door of the milk-room should be double.” (Darton.) While efforts are required to keep the milk-room cool in summer, there may be need of warming in winter. The best means of warming is by hot-water pipes. In some dairies the milk pans stand in a series of troughs on an inclined plane, and all inter-communicating; in this way a current of warm water may be made to surround the pans in winter, and of cold water in summer. Gauze coverings should envelop the pans to exclude insects. Milk pans may be made of glass, glazed earthenware, or tinned iron, 15 to 18 in. across, and less than 6 in. deep.