Some of the advantages and disadvantages of various fuels for residence heating have been mentioned. These and some others are summarized in the table on page 201:

Lighting

Although electricity is in many ways the most desirable form of artificial light, other lights may still have certain advantages. The most effective use of any type of light should be studied for both economic and hygienic reasons.

Types of lights and their care.

Candles

The use of candles is now limited almost entirely to decorative lighting. Candle light is expensive in comparison with other lights.

Kerosene

Kerosene gives a soft light that is easy on the eyes if it is properly shaded by a slightly bluish chimney. The disadvantages of kerosene lighting are the labor of cleaning and filling the lamps, the odor and the vitiation of the air, and the danger of explosion. Following are some suggestions for the care of kerosene lamps:

Table XI. - Advantages and Disadvantages oF Various Fuels and of Electricity 1

Fuel

Advantages

Disadvantages

Wood...........

(a) Cleanliness, (6) cheerful fire, (c) quick increase of heat, (d) cheap in some localities.

(a) Low fuel value, (6) large storage space necessary, (c) labor in preparation, (d) scarcity, (e) does not hold fire long, (/) unsteady heat.

(a) Cleanliness, (6) easy control of fire, (c) easier to realize heat in coal than is the case with other coals, (d) steady heat.

(a) High price, (6) difficulty of obtaining, (c) slower response to change of drafts.

Bituminous coal . .

(a) Low price, (6) availability,

(c) high heat value (in the best grades), (d) low percentage of inert matter (in the best grades).

(a) Dirty, (b) smoke produced, (c) more attention to fire and furnace necessary than with anthracite.

Subbituminous coal and lignite.

(a) Relatively low price, (6) availability (in some regions), (c) responds quickly to opening of drafts.

(a) Slakes and deteriorates on exposure to air, (6) takes fire spontaneously in piles, (c) heat value generally low, (d) heat in fuel difficult to realize, (e) fires do not keep well, (f) gases generated over fire pot sometimes burn in smoke pipe, causing excessive heating.

Peat.............

(a) In general, the same as for wood.

(a) Low heat value, (6) bulkiness.

Coke............

(a) Cleanliness, (b) responds quickly to opening of drafts, (c) fairly high heat value.

(a) Bulkiness, (6) liability of fire going out if not properly handled, (c) fire requires rather frequent

Oil..............

(a) High heat value, (b) immediate increase of heat, (c) cleanliness, (d) small storage space necessary.

attention unless fire pot is deep, (a) High price, (6) difficulty of safe storage.

Gas.............

(a) Ease of control, (b) cleanliness, (c) convenience, (d) immediate increase of heat.

(a) High price in many places.

(a) High price.

1 L. P. Breckenridge and S. B. Flagg. U. S. Bur. Mines, Tech. Paper 97.

1. Fill lamps daily if they are in use. Do not fill them too full. 2. Keep the wicks low when lamps are not lighted. 3. Do not turn the wicks low when the lamps are lighted, because too little air is allowed for burning, and ill-smelling gases are given off. 4. Blow out a lamp by a cross-wise motion at the top. Do not blow into the chimney. A paper may be held at the top on one side and a current of air directed against it. 5. Occasionally boil the burners in a solution of washing-soda or in strong soapsuds.

Acetylene, air gas, and Blau gas.

Lighting by acetylene, air gas, or Blau gas is fairly common in village and country homes. It is, however, in general more expensive than the gas or electric light available in larger towns. Acetylene gives a brilliant white light. Its greatest disadvantage is the danger of explosion from careless handling. The products of combustion are not given off in great amounts.

Gas

Mantles should always be used on gas burners, since they give much more and a steadier light for a given amount of gas than does an open flame (Fig. 46). The saving in gas will more than pay for the lamp and mantles. The tubes of drop lights and stoves should be handled carefully in order to prevent their cracking and allowing gas to escape.