t, but we will have him investigated nevertheless,
and will guard against future visitors here."

Turning to the telephone, he called the private number of a well-known
detective.

"Prescott? Crane speaking. Sorry to get you out of bed, but I should
like to have a complete report upon Dr. Marc C. DuQuesne, of the Rare
Metals Laboratory, as soon as possible. Every detail for the last two
weeks, every move and every thought if possible. Please keep a good man
on him until further notice.... I wish you would send two or three
guards out here right away, to-night; men you can trust and who will
stay awake.... Thanks. Good night."

CHAPTER V

Direct Action

Seaton and Crane spent some time developing the object-compass. Crane
made a number of these instruments, mounted in gymbals, so that the
delicate needles were free to turn in any direction whatever. They were
mounted upon jeweled bearings, but bearings made of such great strength,
that Seaton protested.

"What's the use, Mart? You don't expect a watch to be treated like a
stone-crusher. That needle weighs less than half a gram. Why mount it as
though it weighed twenty pounds?"

"To be safe. Remember the acceleration the Lark will be capable of, and
also that on some other worlds, which we hope to visit, this needle will
weigh more than it does here."

"That's right, Mart, I never thought of that. Anyway, we can't be too
safe to suit me."

When the compasses were done and the power through them had been
adjusted to one-thousandth of a watt, the lowest they could maintain
with accuracy, they focused each instrument upon one of a set of most
carefully weighed glass beads, ranging in size from a pin-head up to a
large marble, and had the beads taken across the country by Shiro, in
order to test the sensitiveness and accuracy of the new instruments. The
first test was made at a distance of one hundred miles, the last at
nearly three thousand. They found, as they had expected, that from the
weight of the object and the time it took the needle to come to rest
after being displaced from its line by a gentle tap of the finger, they
could easily calculate the distance from the compass to the object. This
fact pleased Crane immensely, as it gave him a sure means of navigation
in space. The only objection to its use in measuring earthly distances
was its extreme delicacy, the needle focused upon the smallest bead in
the lot at a distance of three thousand miles c