ng south the angle of our latitude--that's thirty-nine
degrees--away from the perpendicular. I couldn't shoot off on a tangent,
as some of these hot-heads have been claiming. Inertia would make me
keep pace, approximately, with the earth in its rotation. I would rise
slowly--only as fast as the tangent departs from the curvature of the
earth's surface. I haven't figured out how fast that is, but it must be
pretty slow."

"Pretty slow?" Crane smiled. "Figure it out."

"All right--but I'll bet it's slower than the rise of a toy balloon."
Seaton threw down the papers and picked up his slide-rule, a twenty-inch
trigonometrical duplex. "You'll concede that it is allowable to neglect
the radial component of the orbital velocity of the earth for a first
approximation, won't you--or shall I figure that in too?"

"You may ignore that factor."

"All right--let's see. Radius of rotation here in Washington would be
cosine latitude times equatorial radius, approximately--call it
thirty-two hundred miles. Angular velocity, fifteen degrees an hour. I
want secant fifteen less one times thirty-two hundred. Right? Secant
equals one over cosine--um-m-m-m--one point oh three five. Then point oh
three five times thirty-two hundred. Hundred and twelve miles first
hour. Velocity constant with respect to sun, accelerated respecting
point of departure. Ouch! You win, Mart--I'd kinda step out! Well, how
about this, then? I'll put on a vacuum suit and carry rations. Harness
outside, with the same equipment I used in the test flights before we
built _Skylark I--plus_ the new stuff and a coil. Then throw on the
zone, and see what happens. There can't be any jar in taking off, and
with that outfit I can get back O. K. if I go clear to Jupiter!"

Crane sat in silence, his keen mind considering every aspect of the
motions possible, of velocity, of acceleration, of inertia. He already
knew well Seaton's resourcefulness in crises and his physical and mental
strength.

"As far as I can see, that might be safe," he admitted finally, "and we
really should know something about it besides the theory."

"Fine, Mart--let's get busy! I'll be ready in five minutes. Yell for the
girls, will you? They'd break us off at the ankles if we pull anything
new without letting them in on it."

A few minutes later the "girls" strolled out into Crane Field, arms
around each other--Dorothy Seaton, her gorgeous auburn hair framing
violet eyes and vivid coloring; blac