s country at the present time has been estimated by
various experts between 5,000,000,000 and 20,000,000,000 barrels, the
best estimate being about 7,000,000,000. The annual consumption is now
about 400,000,000 barrels. These figures do not take into account the
oil which may be distilled from the rich shale deposits. Apparently this
source will yield a hundred billion barrels of oil. In a similar manner
the coal-supply is diminishing and the consumption is increasing. In
1918 more than a half-billion tons of coal were shipped from the mines.
The production of natural gas perhaps has reached its peak, and, owing
to its relation to the coal and oil deposits, its supply is limited.

Although only a fraction of the total production of gas, oil, and coal
is used in lighting, the limited supply of these products emphasizes the
desirability of developing the enormous water-power resources of this
country. The present generation will not be hard pressed by the
diminution of the supply of gas, oil, and coal, but it can profit by
encouraging and even demanding the development of water-power.
Furthermore, it is an obligation to succeeding generations to harness
the rivers and even the tides and waves in order that the other
resources will be conserved as long as possible. Science will continue
to produce more efficient light-sources, but the cost of light finally
is dependent upon the cost of the energy supplied to these lamps. At the
present time water-power is the anchor to the windward.

XVII

LIGHT AND SAFETY

It is established that outdoors life and property are at night safer
under adequate lighting than they are under inadequate lighting. Police
departments in the large cities will testify that street-lighting is a
powerful ally and that crime is fostered by darkness. But in reckoning
the cost of street-lighting to-day how many take into account the value
of safety to life and property and the saving occasioned by the
reduction in the police-force necessary to patrol the cities and towns?
Owing to the necessity of darkening the streets in order to reduce the
hazards of air-raids, London experienced a great increase in accidents
on the streets, which demonstrated the practical value of
street-lighting from the standpoint of accident prevention.

During the war, when dastardly traitors and agents of the enemy were
striking at industry, the value of lighting was further recognized by
the industries, with the resu