Explosion

 "Louisa and Mr. Harthouse strolled out into the garden, where their voices could be heard in the stillness, though not what they said. Mrs. Sparsit, from her place at the backgammon board, was constantly straining her eyes to pierce the shadows without. 'What's the matter, ma'am? ' said Mr. Bounderby; 'you don't see a Fire, do you?'"(emphasis mine).

Fire, which has served as a symbol of imagination during the entirety of the text, is again highlighted in the chapter, "Explosion"; using Louisa as a symbol of an internal fire. Bounderby, a man who has devoted himself to the removal of "fancies", has spent his life seeking to remove this inner fire from all individuals. Because of this eternal search, the irony of Bounderby asking Mrs. Sparsit if she sees a fire, when in reality she is watching Louisa and Mr. Harthouse, suggests that Louisa's inner fire is being searched for so it may be put out - just like how a literal fire would be - by Bounderby. Also, the description of Mrs. Sparsit trying to "pierce" the characters, again hints at the idea that what is being searched for, is within the characters, and beyond casual observation. The description of the characters as shadows, something without light, is also symbolic of the characters outwardly appearance of being fact based. Despite this appearance as a shadow, the inner light within Louisa remains, even if it is being slowly snuffed out by Bounderby. Because of the enduring nature of Louisa's inner fire, Dickins is suggesting the one's creativity cannot be shunned within a person forever, because regardless of all attempts, this inner fire will burn on, even when trapped within the shadows of one's life.