xxvi AUTHORS CONSULTED. 



POWELL, BADEN . . . History of Natural Philosophy. The 



Unity of Worlds and of Nature. 



PREECE .... On the Telephone. 



PRESTON .... Treatise on the Theory of Light. 



PREVOST-PARADOL . . Histoire Universelle. 



PRICHARD .... Physical History of England. 



PRIESTLEY .... History of Vision. On Different Kinds 



of Air. 



PROCTOR . . . . Essay on Astronomy. The Universe. 



Other Worlds than Ours. Shooting 

 Stars and Meteors. The Sun. Transit 

 of Venus. 



QUATREFAGES . . . Races Humaines. 



REES Cyclopaedia. 



REMSEN . . . . The Elements of Chemistry. 



RENAN Averroes. 



RODWELL, G. F. . . . Birth of Chemistry. Dictionary of Science. 



ROMANES .... Scientific Evidences of Organic Evolution. 



ROSCOE . . . . Spectrum Analysis. 



ROSSITER . i . . Physics. 



RUMFORD .... Essays. 



ST. HILAIRE, GEOFFROY . Zoologie Generate. 



SCROPE Volcanoes. 



SENECA .... Quaestionum Naturalium Libri Septem. 



SISMONDI .... History of Southern Literature. 



SMILES Lives of Boulton and Watt. 



SMITH, ADAM . . . The Wealth of Nations. 



SMITH, PIAZZI . . . The Great Pyramid. 



SPEDDING , . . . Bacon's Works. 



SPENCER, HERBERT . . See HERBERT SPENCER. 



SPRENGEL .... Histoire de la Mddecine. 



STEWART, BALFOUR . . On Heat. Lessons in Elementary Physics. 



STEWART AND GEE . . Lessons in Elementary Practical Physics. 



STUART MILL . . See MILL. 



TAIT Heat. 



TAYLOR .... Sound and Music. 



THOMSON, DR. . . . Outlines of the Necessary Laws of 



Thought. 



THOMSON, J. J. . . .A Treatise on the Motion of Vortex Rings. 

 THOMSON, SIR W. . . Electrostatics and Magnetism. Popular 



Lectures and Addresses. 

 TODHUNTER .... A History of the Mathematical Theory of 



Probability. 

 TYLOR Anthropology. 



