ector.
With it gone, and all their tools and instruments and notes, there was
simply nothing.

As Ken considered the problem, it seemed to him the situation was not as
bad as first appeared. The most important thing had not been lost. This
was the knowledge, locked in their own minds, of what means could
prevail against the dust. Beyond this, the truly essential mechanical
elements for starting over again were also available.

Art Matthews had been very busy, and he had parts enough for six more
motor-generator sets. These were decontaminated and sealed in protective
packing. It would be only a matter of hours to assemble one of them, and
that would power any supersonic projector they might choose to build.

And they _could_ still choose to build one. In the radio supply stores
of the town, and in the junk boxes of the members of the science club,
there were surely enough components to build several times over the
necessary number of generator elements. In the barns and chicken sheds
of the valley there was plenty of aluminum sheeting to build reflectors.

The more he considered it, the more possible it seemed to take up from
where they had left off the night before the fire. There was one
important question Ken asked himself, however: Why stop with a replica
of the small pilot model they had built on the roof of Science Hall?

As long as they were committed to building a projector to test for
effectiveness, they might as well build a full-scale instrument, one
that could take its place as an actual weapon against the dust. If there
were errors of design, these could be changed during or after
construction. He could see no reason at all for building a mere 30-foot
instrument again.

The greatest loss suffered in the fire was that of the chemistry
laboratory and its supplies and reagents. Materials for running tests on
the dust could not be replaced, nor could much of their microchemical
apparatus. The electron microscope, too, was gone. These losses would
have to be made up, where necessary, by having such work done by
Pasadena, Schenectady or Detroit. If the projector were as successful as
all preliminary work indicated, there would be little need for further
testing except as a matter of routine check on the concentration of dust
in the atmosphere.

Before approaching his father, Ken talked it over with his fellow
members of the science club. He wanted to be sure there was no loophole
he was overlooking.

"L