Part one deals with questions relating to heat such as the sources of heat and its effects on humans and animals, while Part two deals with questions relating to air, explaining why metal rusts in air, the operation of barometers and the transmission of sound. A Miscellaneous section[Notes 1] deals with several more nebulous questions, including questions about sleep and dreaming. Within each part, the different chapters break the questions and answers up into subject areas organised thematically.