link to the book At the Mountains of Madness
I encountered this sentence and can only guess what it means, but I want to know for sure
They were normally shapeless entities composed of a viscous jelly which looked like an agglutination of bubbles; and each averaged about fifteen feet in diameter when a sphere. They had, however, a constantly shifting shape and volume; throwing out temporary developments or forming apparent organs of sight, hearing, and speech in imitation of their masters, either spontaneously or according to suggestion.
Does the phrase 'when a sphere' - when you deal with a sphere mean? If not - I appreciate the right answer then