Notes
Originally published in Ellery Queen's Mystery Magazine, May 1970. The story has no speculative elements - it is a chemistry-tied number enigma.
Publications (9)
| Date | Publication | Publisher | Type | Page |
|---|---|---|---|---|
| May 1970 | Ellery Queen's Mystery Magazine, May 1970 | Davis Publications | MAGAZINE | 88 |
| August 1986 | The Best Mysteries of Isaac Asimov | Doubleday & Company | Collection | 316 |
| 1987 | The Best Mysteries of Isaac Asimov | Grafton Books | Collection | 316 |
| September 1987 | The Best Mysteries of Isaac Asimov | Fawcett Gold Medal / Ballantine | Collection | 366 |
| May 1989 | The Asimov Chronicles: Fifty Years of Isaac Asimov | Dark Harvest | Collection | 477 |
| May 1989 | The Asimov Chronicles: Fifty Years of Isaac Asimov | Dark Harvest | Collection | 477 |
| 1991 | The Asimov Chronicles: Fifty Years of Isaac Asimov | Legend | Collection | 588 |
| April 1991 | The Asimov Chronicles: Fifty Years of Isaac Asimov!: Volume Five | Ace Books | Collection | 34 |
| October 1991 | The Asimov Chronicles: Fifty Years of Isaac Asimov: Volume Two | Legend | Collection | 103 |