caught the signal and kicked the engine into life; with a
grind of gears it moved forward toward the river's edge. There was an
indrawn gasp from the crowd as the front wheels ground over the marble
parapet--then the truck was plunging down toward the muddy waters of the
Potomac.

The wheels touched the water and the surface seemed to sink while taking
on a strange glassy character. The truck roared into high gear and rode
forward on the surface of the water surrounded by a saucer-shaped
depression. It parked two hundred yards off shore and the soldiers,
goaded by the sergeant's bark, leapt out and lined up with a showy
_present arms_.

The general returned the salute and waved to the remaining vehicles.
They moved forward in a series of maneuvers that indicated a great
number of rehearsal hours on some hidden pond. The tanks rumbled slowly
over the water while the jeeps cut back and forth through their lines in
intricate patterns. The trucks backed and turned like puffing
ballerinas.

The audience was rooted in a hushed silence, their eyeballs bulging.
They continued to watch the amazing display as General Wingrove spoke
again:

"You see before you a typical example of Army ingenuity, developed in
Army laboratories. These motor units are supported on the surface of the
water by an intensifying of the surface tension in their immediate area.
Their weight is evenly distributed over the surface, causing the shallow
depressions you see around them.

"This remarkable feat has been accomplished by the use of the
_Dornifier_. A remarkable invention that is named after that brilliant
scientist, Colonel Robert A. Dorn, Commander of the Brooke Point
Experimental Laboratory. It was there that one of the civilian employees
discovered the Dorn effect--under the Colonel's constant guidance, of
course.

"Utilizing this invention the Army now becomes master of the sea as well
as the land. Army convoys of trucks and tanks can blanket the world. The
surface of the water is our highway, our motor park, our
battleground--the airfield and runway for our planes."

Mechanics were pushing a Shooting Star onto the water. They stepped
clear as flame gushed from the tail pipe; with the familiar whooshing
rumble it sped down the Potomac and hurled itself into the air.

"When this cheap and simple method of crossing oceans is adopted, it
will of course mean the end of that fantastic medieval anachronism, the
Navy. No need for billion-do