Continuity mistake: In chapter 63, Pendergast is mixing chemicals and accidentally spills a few drops of sulfuric acid on Smithback's hand. At the bottom of page 357 (of the hardcover edition), Pendergast grabs "a small box of baking soda, ripped off the top." In the very next paragraph, "Pendergast shook baking powder over the burn mark." Baking soda and baking powder are VERY different chemicals; the soda would have been the option for a burn, because it would neutralize the acid, while baking powder would do nothing. A simple but obvious error.