. Its working parts are very simple. They consist of a
standard light source, in this case an electric light, a
photo-electric cell which detects differences in the amount of light
impinging on it, a radio tube which amplifies the signal received from
the photo-electric cell and which operates the relays controlling the
automatic valves.

"Between the electric light and the photo-electric cell is placed a
glass vessel holding an alkali that is to be neutralized. Above is a
tube from which an acid passes, drop by drop, through an automatic
valve, into the alkali. A small amount of chemical indicator added to
the alkali maintains a red color in it until it is neutralized. When a
sufficient amount of the acid has dropped into the alkali, the red
color disappears, indicating complete neutralization.

"When the solution is colored red, an insufficient amount of lights
gets through to the photo-electric cell. As the red color gradually
diminishes, the amount of light passing through increases, and when
the solution is entirely clear the light reaches a critical value
which causes the photo-electric cell to pass a signal to the radio
tube. This tube operates the relay which closes a valve and shuts off
the supply of acid.

"Using a device of this sort to perform such operations around a
laboratory will save a great deal of a chemist's time. Its electric
eye is about 165 times as sensitive to differences in color as any
human eye."

Beyond the Vanishing Point

A COMPLETE NOVELETTE

_By Ray Cummings_

CHAPTER I

_The Fragment of Quartz_

[Sidenote: The tale of a golden atom--an astounding adventure in
size.]

[Illustration: The fly landed with a thud on the center table.]

It was shortly after noon of December 31, 1960, when the series of
weird and startling events began which took me into the tiny world of
an atom of gold, beyond the vanishing point, beyond the range of even
the highest-powered electric-microscope. My name is George Randolph. I
was, that momentous afternoon, assistant chemist for the Ajax
International Dye Company, with main offices in New York City.

It was twelve-twenty when the local exchange call-sorter announced
Alan's connection from Quebec.

"You, George? Look here, we've got to have you up here at once.
Chateau Frontenac, Quebec. Will you come?"

I could see his face imaged in the little mirror on my desk; the
anxiety, tenseness in his voice, was duplicated in his expression.