"Chemistry" begins with a description of a pond that becomes the central image of the story. Water plays a part in nearly every event in the work, a tale of loss and damaged family relationships. The narrator's father has died, his plane lost in the Irish Sea, and the narrator's mother and he have moved in with his grandfather. The trouble arises when Ralph, the mother's new boyfriend moves in. The grandfather resents Ralph's presence and protests at every moment. The reader learns that the narrator and his grandfather used to play on the pond with a battery-operated motor launch, which sinks and is lost as the story opens. This sinking mirrors for the boy the watery death of his father and foreshadows the watery death of his grandfather.
The title comes from the grandfather's profession. He is a retired chemist, and now experiments a little in his home. There is a sense of both magic and danger about the grandfather as the narrator asks him questions about all the different chemicals. The final item on his shelf is green vitriol, or as the grandfather says, "Laurel water. Prussic Acid. Not for drinking" (p.144), presenting to the reader the idea of treacherous water.
Using what his grandfather has taught him about acids, the narrator plots to throw acid at Ralph to burn his face. This will make Ralph ugly, he thinks, so that his mother will stop paying so much attention to him and more to his grandfather. That night, however, his grandfather commits suicide by drinking the laurel water. The boy dreams that his father comes to him in his sleep, his hair wet, his lips and clothes caked with salt and covered with seaweed. "It was her," says the father's ghost, referring to the mother, "She made a hole in the bottom of the [battery operated toy] boat... so it would sink. The boat sank -- like my plane" (p.146). With this ghostly image the story winds to a close. The boy throws his unused bottle of acid into the pond to join his sunken boat. Water in its different forms has taken almost everything important in the narrator's life.