Chapter V: Captive Molecules; the Story of the Steam-Engine

(p. 82). The experiments of Hero of Alexandria. For a full account of the experiments see vol. I., pp. 249, 250.

(p. 84). The Marquis of Worcester's steam engine. The original account appeared, as stated, in the Marquis of Worcester's _Century of Inventions_, published in 1663.

(p. 92). Newcomen's engine. As stated in the text, the account of Newcomen's engine is quoted from the report of the Department of Science and Arts of the South Kensington Museum, now officially known as the Victoria and Albert Museum.

(pp. 107-109). James Watt. The characterization of Watt here given is taken from an article in an early edition of the Edinburgh Encyclopædia published about the year 1815.