=Potatoes= ought to be boiled in their jackets, or steamed, to avoid loss of nitrogenous material and salts. Moist heat causes the starch granules to swell, and ultimately softens and bursts the cellulose envelopes in which these are contained. Dry heat, as when potatoes are baked, converts starch into a soluble form, and ultimately into dextrine (= C₆H₁₀O₅), an intermediate stage towards the formation of dextrose (_i.e._ glucose = C₆H₁₂O₆). =Peas and Beans= ought to be boiled slowly and for a long time to render them more digestible. If old, they ought to be soaked in cold water for twenty-four hours, then crushed, and stewed. Hard water must be avoided in the cooking of peas and beans as well as of other vegetables, as the lime-salts form insoluble compounds with legumin. =Green vegetables= require thorough and prolonged cooking. This renders their tissues softer and more easily attacked in digestion. The members of the cabbage tribe and carrots can hardly be boiled too long. Soft water ought always to be used; this is one reason why steaming is preferable. Before boiling, all vegetables should be well washed in cold water. A little vinegar will remove any insects present. COOKING APPARATUS.—The apparatus required in cooking may be divided into kitchen utensils and cooking ranges. To ensure good cooking, perfect cleanliness of all apparatus is indispensable. The use of the frying-pan, gridiron, spit, and oven has been sufficiently indicated under the description of the different methods of cooking. The form of stove to be used for cooking meat is gradually being settled against the old open stove. Although this secures a somewhat more savoury joint than when meat is baked, it is extravagant in working. The closed kitchener in which coal is employed is less economical than a gas stove at the present price of gas, if the latter is carefully used. Various appliances for economising fuel have been devised, and at the same time of allowing of the prolonged action of a moderate degree of heat. These are usually constructed on the principle of an ordinary bath, consisting of a double pan, with a layer of water between the two compartments. Warren’s cooking-pot belongs to this type. The Aladdin oven consists of an iron box with an opening above to let off superfluous steam. This box is surrounded by another composed of non-conducting material, while a lamp below furnishes the heat. Dr. Atkinson has calculated that in an ordinary oven 2 lbs. of fuel must be expended for every pound of food cooked, while in his Aladdin oven 2½ lbs. of fuel will cook 60 lbs. of food. Time is an important element in cooking. Food is most thoroughly cooked and most digestible when subjected to a temperature below that of boiling water for a prolonged period.