xxii CONTENTS. 



LECTURE XXXVII. 

 ON PHYSICAL OPTICS, 340. 



Sources of light ; Combustion ; Slow decomposition ; Electricity ; Friction, 

 340. Solar phosphori ; Emission of light; Velocity of light, 341. Apparent 

 aberration ; Oblique reflection ; Diffraction ; Dispersion, 342. Colour ; Division 

 of the spectrum ; Light of different kinds, 343. Mixed lights ; Imitation of white 

 light ; Primitive colours, 344. Mixture of colours by rapid motion ; Combina- 

 tions ; Atmospherical refraction, 345. Horizontal refraction ; Rainbows, 346. 

 Halos and parhelia, 347. Refraction of ice ; Complicated halos ; Double refrac- 

 tion ; Iceland spar, 348. Second refraction ; Transparent plates, 349. 



LECTURE XXXVIII. 

 ON VISION, 350. 



Description of the eye, 350. Image on the retina ; Advantages of the arrange- 

 ment; Inversion of the image, 351. Instinct; Sensibility of the retina, 352. 

 Focus of the eye; Accommodation; Change in the crystalline lens, 353. Uses 

 of the iris ; Optometer ; Myopic sight, 354. Presbyopic sight ; Single vision ; 

 Judgment of distance, 355. Apparent magnitudes of the sun and moon ; Aerial 

 perspective ; Painting ; Panorama, 356. Duration of sensations ; Ocular spectra, 

 357. 



LECTURE XXXIX. 



ON THE NATURE OF LIGHT AND COLOURS, 359. 



Theories respecting the nature of light ; Simple propagation, 359. Transparent 

 mediums, 360. Uniformity of velocity ; Reflection and refraction, 361. Partial 

 reflection ; Total reflection ; Sources of light, 362. Aberration ; Double refrac- 

 tion ; Dispersion, 363. Colours of thin plates ; Alternate union and extinction 

 of colours ; Light admitted by two holes, 364. Supposed dimensions of undula- 

 tions ; Correction ; Stripes in a shadow, 365. Light passing through a narrow 

 aperture ; Colours of striated surfaces ; Curved stripes of colours, 366. Fringes 

 near a shadow; Colours of thin plates, 367. Colours of natural bodies, 368. 

 Colours of mixed plates ; Supernumerary rainbows ; Colours of concave mirrors, 

 369. Agreement of the Huygenian theory with the phenomena ; Interference of 

 light, 370. Phenomena of polarized light; Double refraction, 371, 372. Re- 

 ferences, 372. 



LECTURE XL. 

 ON THE HISTORY OF OPTICS, 374. 



Knowledge of the ancients; Empedocles; Aristotle, 374. Archimedes; 

 Euclid; Ptolemy; Alhazen; Vitellio; R. Bacon; Janson, 375. Galileo, 

 Kepler ; Scheiner ; Rheita ; Maurolycus ; De Dominis ; Snellius ; Descartes ; 

 Fermat ; Leibnitz ; Barrow, 376. Boyle : Hooke ; Newton ; Grimaldi, 377. Bar- 

 tholin; Huygens; Roemer,378. Bradley; Bouguer; Porterfield; Jurin; Smith; 

 Dollond ; Hall, 379. Euler; Lambert, 380. Mathemetical opticians ; Mazeas ; 

 Dutour; Comparetti ; Priestley; Delaval, 381. R. Darwin; Atmospherical 

 refraction; Wollaston ; Ritter; Herschel; Laplace; Attempts of the author, 

 382. Chronological table, 385. 



