06. In selecting a fuel for any certain service, the characteristics of each variety should be well considered. The value of a fuel depends primarily upon the amount of heat which it will give off during combustion, but this is modified by the amount of labor and care required in its use.

The following points should be studied carefully:

1. The amount of labor required for feeding and cleaning the fires.

2. The amount of the ashes, and the labor or cost of removing them.

3. The labor required for cleaning out the soot and dust from the boiler and its settings.

4. The liability to produce smoke, and the cost of the necessary arrangements to prevent it.

5. The extent and cost of the storage required for the fuel, and for the ashes.

6. The cost of the fuel, delivered upon the premises.

If the ash is easily fusible it will melt and run together, forming large blocks of clinkers. This will add greatly to the labor required to keep the fire in good order.

The practice of burning a mixed fuel, that is, a mixture of coarse and fine coal, is a wasteful one. The small pieces burn to ashes before the large lumps are completely consumed.

67. Storage Of Fuel

Storage Of Fuel. Coal of all kinds should be carefully protected from the weather. When it is alternately wet and dry, it is slowly oxidized, and the damage is proportional to the richness of the coal in volatile matter. Even hard anthracite suffers considerable damage by exposure.

The space required for the storage of fuel, in cubic feet for each thousand pounds of material, is about as follows: