52. QUALITY OF COAL.--In addition to knowing the names, prices, and uses of the different kinds of coal, the housewife should be able to distinguish poor coal from good coal. In fact, proper care should be exercised in all purchasing, for the person who understands the quality of the thing to be purchased will be more likely to get full value for the money paid than the one who does not. About coal, it should be understood that good hard coal has a glossy black color and a bright surface, whereas poor coal contains slaty pieces. The quality of coal can also be determined from the ash that remains after it is burned. Large chunks or great quantities of ash indicate a poor quality of coal, and fine, powdery ash a good quality. Of course, even if the coal is of the right kind, poor results are often brought about by the bad management of a fire, whether in a furnace or a stove. Large manufacturing companies, whose business depends considerably on the proper kind of fuel, buy coal by the heat units--that is, according to the quantity of heat it will give off--and at some future time this plan may have to be followed in the private home, unless some other fuel is provided in the meantime.
Mixed with poor coal are certain unburnable materials that melt and stick together as it burns and form what are known as clinkers. Clinkers are very troublesome because they often adhere to the stove grate or the lining of the firebox. They generally form during the burning of an extremely hot fire, but the usual temperature of a kitchen fire does not produce clinkers unless the coal is of a very poor quality. Mixing oyster shells with coal of this kind often helps to prevent their formation.
53. COKE.--Another fuel that is sometimes used for cooking is coke. Formerly, coke was a by-product in the manufacture of illuminating gas, but now it is manufactured from coal for use as a fuel. Because of the nature of its composition, coke produces a very hot fire and is therefore favorable for rapid cooking, such as broiling. However, it is used more extensively in hotels and institutions than in kitchens where cooking is done on a small scale.
GAS
54. VALUE OF GAS AS FUEL.--As a fuel for cooking purposes, gas, both artificial and natural, is very effective, and in localities where the piping of gas into homes is possible it is used extensively. Of the two kinds, artificial gas produces the least heat; also, it is the most expensive, usually costing two or three times as much as natural gas. Both are very cheap, however, considering their convenience as a kitchen fuel. Heat from gas is obtained by merely turning it on and igniting it, as with a lighted match. Its consumption can be stopped at once by closing off the supply, or it can be regulated as desired and in this way made to give the exact amount of heat required for the method of cookery adopted. Neither smoke nor soot is produced in burning gas if the burners of the gas stove are adjusted to admit the right amount of air, and no ashes nor refuse remain to be disposed of after gas has been burned. Because gas is so easily handled, good results can be obtained by those who have had very little experience in using it, and with study and practice results become uniform and gas proves to be an economical fuel.
55. MEASUREMENT OF GAS.--Gas is measured by the cubic foot, and a definite price is charged for each 1,000 cubic feet. To determine the
quantity used, it is passed through what is called a meter, which measures as the gas burns. It is important that each housewife be able to read the amount registered by the meter, so that she can compare her gas bill with the meter reading and thus determine whether the charges are correct. If only the usual amount of gas has been consumed and the bill does not seem to be correct or is much larger than it has been previously, the matter should be reported to the proper authorities, for the meter may be out of order and in need of repair.
56. READING A GAS METER.--To register the quantity of gas that is consumed, a gas meter, as is shown in Fig. 1, is provided with three large dials, each of which has ten spaces over which the hand, or indicator, passes to indicate the amount of gas consumed, and with one small dial, around which the hand makes one revolution every time 2 cubic feet of gas is consumed. This small dial serves to tell whether gas is leaking when the stoves and lights are not turned on. Above each large dial is an arrow that points out the direction in which to read, the two outside ones reading toward the right and the center one toward the left; also, above each dial is lettered the quantity of gas that each dial registers, that at the right registering 1,000 cubic feet, that in the center 10,000 cubic feet, and that at the left 100,000 cubic feet. To read the dials, begin at the left, or the 100,000 dial, and read toward the right. In each instance, read the number over which the hand has passed last. For instance, when, as in Fig. 1, the hand lies between 5 and 6 on the left dial, 5 is read; on the center dial, when the hand lies between 5 and 6, 5 is read also; and on the right dial, when the hand lies between 2 and 3, the 2, which is really 200, is read.
57. To compute the quantity of gas used, the dials are read from left to right and the three readings are added. Then, in order to determine the quantity burned since the previous reading, the amount registered at that time, which is always stated on the gas bill, must be subtracted from the new reading.