Page:Fantastic v08n11 1959-11.djvu/47

will pass the time—as you see, Olafson's Hole is a deep one and the way to it is long.

The Folly is a tiny hermetically sealed chamber filled with air under the constant pressure of one atmosphere. Every five seconds a knife-edged wall descends swiftly through its midst, cutting it into two chambers. In each of these two chambers the pressure of the air is automatically measured with an accuracy of five figures. Then the dividing wall flies up, the Folly becomes one chamber again, and the process is repeated. With Olafson's help I try to keep it operating 24 hours a day. There are occasional breakdowns, but we have had it slashing air and measuring pressure continuously for periods as long as 15 months. It is in its seventh month this time.

Somewhere in my pockets I should have a section of the record it taps out like a veritable stock ticker—I have compromised enough with modern methods to let one of the young men hook on a typewriting device that commits the air pressure measurements to a paper tape. Here it is! See, the left-hand column records the pressures in Chamber A and the right hand column the pressures that simultaneously exist in Chamber B—taking the pressure inside the Folly as unity.

As you can plainly see, the readings do not differ by more than two ten-thousandths—the Folly's permissable margin of error in measurement. I have yards and yards of such figures, all showing the same boresome invariability. Once I spotted a reading of .99997 and my heart skipped a beat, but the reading was the same in the other chamber—the Folly had merely sprung a slow leak and the air pressure outside was lower.

Well may you ask, Di, even though you did audit the elementary survey . . .you know, I really should remember you, I should remember such a lovely young lady. I am growing old, I fear, and my memory has become an ungallant traitor, while you are exceptionally young to be bothering about alumni reunions and calls on old profs . . . Well may you ask, Di, why I should expect the air pressure in the two chambers ever to differ, why I should have Olafson