Note: This essay consists of two separate sections, "The Silicone World" and "The Fluorine Planet". It was published three times between 1952 and 1983. The first publication was in ''The Petrified Planet'' (1952), the second one in ''Startling Stories December 1952'' (as "The Silicone World" as by Fletcher Pratt even though it contained both sections of the essay), the third one in the Ace edition of ''Uller Uprising'' in 1983. The 2006 ebook by Project Gutenberg was transcribed from the 1983 Ace edition. The three published texts are very similar, but not quite identical. The ''Startling Stories'' version (signed by Pratt) omits at least two paragraphs, alters the contents of the first paragraph and slightly changes various numbers (distances, temperatures, etc). The Ace version reverts to the original Clark text, but changes capitalization ("earth" vs. "Earth") and punctuation (semicolon vs. full stop) on a few occasions. It also adds a few linking words throughout to make the style appear less "telegraphic". Both Pratt and Clark have letters concerning the authorship of the article in the March 1953 issue of "Startling Stories". While Pratt concedes that Clark is mostly responsible for the essay that appeared in the magazine he also states that the "the original impulse" for the concepts came from the authors.