The same method is employed in the dwelling-house shown in a preceding chapter. A cast-iron pipe is made in sections, which are to be united, and the whole fastened at top and bottom in the centre of the warm-air flue by ears extending to the bricks, and fastened when the flue is in process of building. Projecting openings to receive the pipes of the furnace, the laundry stove, and two stoves in each story, should be provided, which must be closed when not in use. A large opening is to be made into the warm-air fine, and through this the kitchen stove-pipe is to pass, and be joined to the cast-iron chimney-pipe. Thus the smoke of the kitchen stove will warm the iron chimney-pipe, and this will warm the air of the flue, causing a current upward, and this current will draw the heat and smells of cooking out of the kitchen into the opening of the warm-air flue. Every room surrounding the chimney has an opening at the top and bottom into the warm-air Hue for ventilation, as also have the bathroom and water-closets. [Illustration: Fig. 30.] The writer has examined the methods most employed at the present time, which are all modifications of the two modes here described. One is that of Robinson, patented by a Boston company, which is a modification of the mining mode. It consists of the two ventilating tubes, such as are employed in mines, united in one shaft with a roof to keep out rain, and a valve to regulate the entrance and exit of air, as illustrated in Fig. 30. This method works well in certain circumstances, but fails so often as to prove very unreliable. Another mode is that of Ruttan, which is effected by heating air. This also has certain advantages and disadvantages. But the mode adopted for the preceding cottage plan is free from the difficulties of both the above methods, while it will surely ventilate every room in the house, both by day and night, and at all seasons, without any risk to health, and requiring no attention or care from the family. By means of a very small amount of fuel in the kitchen stove, to be described hereafter, the whole house can be ventilated, and all the cooking done both in warm and cold weather. This stove will also warm the whole house, in the Northern States, eight or nine months in the year. Two Franklin stoves, in addition, will warm the whole house during the three or four remaining coldest months. In a warm climate or season, by means of the non-conducting castings, the stove will ventilate the house and do all the cooking, without imparting heat or smells to any part of the house except the stove-closet.