tures of the sun and its surrounding star field
from this distance. Our only way of getting back is going to be this
series of pictures, so I think we had best make it complete. For the
first light century, we ought to take a picture every ten light years,
and after that one each light century until we reach a point where we
are only getting diminishing pictures of the local star cluster. After
that, we can wait until we reach the edge of the Galaxy."

"Sounds all right to me," agreed Arcot. "After all, you're the
astronomer, I'm not. To tell you the truth, I'd have to search a while
to find Old Sol again. I can't see just where he is. Of course, I could
locate him by means of the gyroscope settings, but I'm afraid I wouldn't
find him so easily visually."

"Say! You sure are a fine one to pilot an expedition in space!" cried
Wade in mock horror. "I think we ought to demote him for that! Imagine!
He plans a trip of a thousand million light years, and then gets us out
seven light years and says he doesn't know where he is! Doesn't even
know where home is! I'm glad we have a cautious man like Morey along."
He shook his head sadly.

They took a series of six plates of the sun, using different
magnifications.

"These plates will help prove our story, too," said Morey as he looked
at the finished plates. "We might have gone only a little way into
space, up from the plane of the ecliptic and taken plates through a wide
angle camera. But we'd have had to go at least seven years into the past
to get a picture like this."

The new self-developing short-exposure plates, while not in perfect
color balance, were more desirable for this work, since they took less
time on exposure.

Morey and the others joined Arcot in the control room and strapped
themselves into the cushioned seats. Since the space strain mechanism
had proved itself in the first test, they felt they needed no more
observations than they could make from the control room meters.

Arcot gazed out at the spot that was their immediate goal and said
slowly: "How much bigger than Sol is that star, Morey?"

"It all depends on how you measure size," Morey replied. "It is two and
a half times as heavy, has four times the volume, and radiates
twenty-five times as much light. In other words, one hundred million
tons of matter disappear each second in that star.

"That's for Sirius A, of course. Sirius B, its companion, is a different
matter; it's a white dwarf. It ha