A/N: Most readers are familiar with the curious case of the dog that didn't bark in the night. (If not, I draw your attention to The Adventure of Silver Blaze). Have you ever heard of the case of the barking dog? Apologies to Stutley in advance regarding my very liberal interpretation of his prompt.
Prompt from Stutley Constable: Smoked glass
The Case of the Barking Dog
"What momentous case merits the dangers of this toxic atmosphere?" Watson choked.
Holmes chuckled with ominous enthusiasm. "It's the case of the barking dog. Come."
The doctor plunged into the vile vapours.
"Note closely as I mix carbon disulfide with nitrous oxide." Holmes expertly swirled the enormous glass cylinder standing before him then touched the mixture's surface with a flame.
"Whoof!" An ear-splitting roar reverberated through the flat as a brilliant blue luminescence plummeted to the tube's bottom.
Watson yelped.
A satisfied smile erupted across the detective's face. "Simple, but an excellent example of chemiluminescence. All that remains is this sulphur coating on the glass. Smoked glass."
"Smoked from the inside and the outside," Watson opened the flat's windows. "It has been a most illuminating experiment, Holmes."
A/N: According to some sources, Justus von Liebig first performed this experiment in 1853 using nitrogen monoxide and carbon disulfide. His demonstration was so well received that Liebig performed it a second time. It did not go quite as expected and a minor explosion gave Queen Therese of Bavaria a small wound on her cheek. Oops.