Here is a fun word used to describe Holmes’ chemical experiment in “The Dancing Men” in The Greatest Adventures of Sherlock Holmes. Poor Dr Watson had to put up with many such experiments during his time with Holmes in the Baker Street rooms.

Malodorous – smelling very unpleasant

Usage: “Holmes had been seated for some hours in silence with his long, thin back curved over a chemical vessel in which he was brewing a particularly malodorous product.”