of the sea. Very fortunately, however, aerial
international law may be written at the very start of the science by a
common international standard and practice, thus obviating the
greatest part of the divergences which long years of habit have
grafted into the maritime laws of the various nations. The slate is
clean so that uniformity may be assured in a law which is soon to come
into the most vital touch with the daily lives of the nations.

Who, for instance, owns the air above the various nations? Obviously
the individual landowner has rights, especially as to freedom from
damage. The nation also has rights, especially for its protection and
for police work. How high, however, does this jurisdiction go? Some
assert that a maximum altitude should be set, say five thousand feet,
above which the air would be as free as the seas; others that each
nation must have unqualified control to the limit of the ether.

Then comes the question of passports, customs, registration, safety
precautions, and damages. As already shown, the man on the ground is
helpless against the airplane which chooses to defy him. People and
goods can cross national lines by the air without passports or
customs. There will be no main ports of entry as in sea or train
commerce, and it is too much to think that any nation can patrol its
whole aerial frontier in all its various air strata. Undesirable
immigrants or small precious freight can be smuggled in with the
greatest ease through the route of the air.

Obviously the most elaborate international rules are necessary. Planes
must have some method of international registration and license, just
as in a more limited sense ships on the seas have what amounts to an
international status. Landing-fields must be established and open to
foreign planes, each nation providing some kind of reciprocal landing
rights to other nations. Arrangements must be made so that if a
monkey-wrench drops out of a plane a mile or two up in the air proper
damages can be collected. For such things there is to-day but little
precedent in law.

This but sketches the problems. It shows, however, how closely this
new science will bind the world together and obliterate national lines
and nationalistic feelings. As the sea has been the great civilizer of
the past, so the air will be the great civilizer of the future.
Through it men will be brought most intimately in touch with one
another and forced to learn to live together as