Doyle wrote a total of 60 Holmes stories and most of the time Sherlock Holmes and Dr. Watson share lodgings in London. Their very lives reflect the superior English education of that era. At 221b Baker Street the conversation is full of mathematical terms such as surds, conic sections, and the fifth proposition of Euclid. We hear about astronomy too: the obliquity of the ecliptic and the dynamics of asteroids. But Holmes is a chemist at heart. Before Watson even meets Holmes he is told by Young Stamford that Holmes “is a first-class chemist.” Almost every one of the tales contains a reference to some chemical. They range from elements like zinc (Zn) and copper (Cu), to industrial chemicals such as sulphuric acid and the dye Tyrian purple. Of course numerous poisons are mentioned, and several are used.