, graduate student.

Mendenhall's interpretations were said to lend weight to the theory that
Beta Cephei is contracting and expanding once in every four and one-half
hours. This is such a terrific rate of speed from a terrestrial point of
view that it appears to be moving toward and away from the earth at a
velocity reaching a maximum of about nine and one-half miles per second.

Beta Cephei is a variable star in the Constellation Cepheus. It is best
visible in the northern sky during July or August. Its distance from the
earth is estimated roughly at 2,000,000,000,000,000 miles, and
Mendenhall estimates its diameter at almost 2,000,000 miles, more than
twice that of the sun.

In addition to the apparent velocity caused by contraction and expansion
of its surface five times a day, Beta Cephei seems to have another
motion. This was said by Mendenhall to be a rotation around some other
star in a period of 20 years. Velocity of this rotation is something
over three miles a second.

Variable stars are of particular interest to astronomers because the
light from them pulsates regularly, flaring and dying as though fuel
were replenished at regular intervals. The rate of this pulsation has
been found to be a measure to the candle power of the star. Its distance
then can be determined by contrasting its actual candle power with the
apparent magnitude as seen from the earth.

[Illustration: _"Oh my God!" gasped Bell. He'd known this man before. A
Secret Service man--one of the seven who had vanished._]

Murder Madness

PART THREE OF A FOUR-PART NOVEL

_By Murray Leinster_

Seven United States Secret Service men have disappeared in South
America. Another is found--a screaming homicidal maniac. It is rumored
that they are victims of a diabolical poison which produces "murder
madness."

[Sidenote: More and more South Americans are stricken with the horrible
"murder madness" that lies in The Master's fearful poison. And Bell is
their one last hope as he fights to stem the swiftly rising tide of a
continent's utter enslavement.]

Charley Bell of the "Trade"--a secret service organization which does
not officially exist--discovers that a sinister system of slavery is
flourishing in South America, headed by a mysterious man known only as
The Master. This slavery is accomplished by means of a poison which
causes its victims to experience a horrible writhing of the hands,
followed by a madness to do murder, two wee