Chapter IV: The Work of Air and Water

On page 63 reference is made to the work of the old Greeks, Archimedes and Ctesibius. An account of Archimedes' discovery of the laws of buoyancy of solids and liquids will be found in vol. I., p. 208.

(p. 64). The machines of Ctesibius and Hero. See vol. I., p. 242 _seq._, for a full account of these mechanisms.

(p. 65). Toricelli, the pupil of Galileo, and his discovery of atmospheric pressure. For a fuller account of his discovery and what came of it see vol. II., p. 120 _seq._

(p. 66). Boyle's experiments on atmospheric pressure. See vol. II., p. 204 _seq._

(p. 66). Mariotte and Von Guericke. See vol. II., p. 210 _seq._

(p. 71). Roman mills. A scholarly discussion of the subject of Roman mills, based on a comprehensive study of the references in classical literature, is given in Beckmann's _History of Inventions_, London, 1846.

(p. 73). Recent advances in water wheels. As stated in the text, the quotation is from an article on _Motive Power Appliances_, by Mr. Edward H. Sanborn, in the _Twelfth Census Report_ of the United States.