The simplest mode of warming a house and cooking food is by radiated heat from fires; but this is the most wasteful method, as respects time, labor, and expense. The most convenient, economical, and labor-saving mode of employing heat is by convection, as applied in stoves and furnaces. But for want of proper care and scientific knowledge this method has proved very destructive to health. When warming and cooking were done by open fires, houses were well supplied with pure air, as is rarely the case in rooms heated by stoves. For such is the prevailing ignorance on this subject that, as long as stoves save labor and warm the air, the great majority of people, especially among the poor, will use them in ways that involve debilitated constitutions and frequent disease. The most common modes of cooking, where open fires are relinquished, are by the range and the cooking-stove. The range is inferior to the stove in these respects: it is less economical, demanding much more fuel; it endangers the dress of the cook while standing near for various operations; it requires more stooping than the stove while cooking; it will not keep a fire all night, as do the best stoves; it will not burn wood and coal equally well; and lastly, if it warms the kitchen sufficiently in winter, it is too warm for summer. Some prefer it because the fumes of cooking can be carried off; but stoves properly arranged accomplish this equally well. After extensive inquiry and many personal experiments, the author has found a cooking-stove constructed on true scientific principles, which unites convenience, comfort, and economy in a remarkable manner. Of this stove, drawings and descriptions will now be given, as the best mode of illustrating the practical applications of these principles to the art of cooking, and to show how much American women have suffered and how much they have been imposed upon for want of proper knowledge in this branch of their profession. And every woman can understand what follows with much less effort than young girls at high-schools give to the first problems of Geometry--for which they will never have any practical use, while attention to this problem of home affairs will cultivate the intellect quite as much as the abstract reasonings of Algebra and Geometry., [Illustration: Fig. 34.]