Fuel gases consist principally of hydrocarbons, that is, of molecular compounds of carbon and hydrogen. The properties of the various gases depend on the number and arrangement of the carbon and hydrogen atoms within their molecules. All these gases are odorless in the pure state, and carbon monoxide is toxic. It is therefore common practice to add sulfur compounds to manufactured gas; such sulfur compounds, which are sometimes normally present in the gas, have an unpleasant smell and serve to give warning of a leak in the supply lines or gas appliance. In addition to their combustible components most gases have varying amounts of noncombustible nitrogen and water as their end products.
Fuel gases still in use are coal gas, made by the destructive distillation of coal producer gas and blast-furnace gas, made by the interaction of steam, air, and carbon; natural gas, drawn from gas deposits in the earth; and bottled gases, made from the lighter hydrocarbons.
Fuel gases still in use are coal gas, made by the destructive distillation of coal producer gas and blast-furnace gas, made by the interaction of steam, air, and carbon; natural gas, drawn from gas deposits in the earth; and bottled gases, made from the lighter hydrocarbons.
