FoodNet

Handbook of domestic science and household arts for use in elementary schools

1900

Page 22

Presented as published in 1900. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
I. Vegetable fuels, as wood, and products of Avood dis- tillation, as methyl or wood alcohol, and charcoal. II. Mineral fuels, as coal, subdivided according to com- position into peat, lignite, cannel coal, bituminous and anthracite ; and products of coal distillation, as coal gas, water gas, and coke. III. Mineral oils and gases, as crude petroleum, from which are derived naphtha, gasolene, benzine, kerosene, and natural gas. IV. Product of fermentation known as ethyl alcohol. "Wood. — Wood, or vegetable fibre, is composed largely of 40 HANDBOOK OF DOMESTIC SCIENCE a carbohydrate, cellulose, Avliich forms the cell wall of all plant life. It belongs to the carbohydrate group because of its composition; but man cannot use it to any extent for food, as he does most other members of the group. See chapter on Starches. Associated with the cellulose in wood are varying amounts of nitrogenous matter, resins, and coloring matters, as well as the mineral products which remain as ashes after com- bustion. In its pure state cellulose may be found in the form of Swedish filter paper. Less pure forms are cotton and linen. Though formerly wood served as the chief fuel, now in the cities it is used mainly as kindling and in fireplaces. Kinds of Wood. — In the markets, wood is roughly classed as either hard or soft. Soft "Wood. — The soft woods, as pine, spruce, fir, hemlock, cedar, and red wood, because of lighter, more spongy tex- ture and large amount of resin, burn very freely, producing a quick, hot fire. They are therefore largely used as the kindling in coal stoves or ranges. The charcoal formed from soft wood is soft and crumbly. Hard Wood. — The harder woods, as oak, hickory, ash, chestnut, maple, birch, poplar, elm, and walnut, are much more dense in structure, contain no resin, and therefore require a higher degree of heat to ignite and are consumed more slowly, thus giving out heat for a much longer time. Because of the small amount of flame produced by combus- tion of these woods, and the large amount of charcoal formed, they are used in culinary operations where live coals are desired. A careful study of their woody structure, and of their condition in the way of dryness, freedom from decay or presence of insects, will aid the investigator in gaining information of economic value. If the wood is damp, then THE KITCHEN 41 in the change of the sap or water into the form of vapor much heat becomes latent and is wasted, from a culinary standpoint. In the beginning of combustion of wood, during the flame stage, all of the hydrogen and part of the carbon pass off as water and as carbon dioxid, and much heat goes witli them, the greater portion becoming latent in changing the water to steam. In the second or glowing coal stage, the waste product is carbon dioxid, which carries off little heat. Therefore the greater the proportion of car- bon in the wood, the higher its heating value.