316 



CATALOGUE. — PHYSICAL OPTICS. 



except that greens appe»» to become bluish when viewed 

 by candlelight ; but in this circumstance there is perhaps no 

 great singularity. 



Debility of sight. 

 Taper tubes assisting weak sight. Ph. tr. 



1G68. ill. 727, 765. 

 Biiggs's case of indistinct vision at night. Ph. 



tr. 1684. IV. 539. 

 Dale on a blindness at night. Ph. tr. 1694. 



XVIII. 158. 



Cataract. 

 Young on the extraction of the cataract. 

 Ed. ess. II. 324. 



Employment for the Blind. 



Cheese's musical machine for the blind. 



S. A .V. 125. 

 Bew on employment in blindness. Manch. 



M. I. 159. 

 Berard's palpable mathematics for the blind. 



B. Melanges, 1 83. 



Some books have been printed in Paris in palpable cha- 

 racters. 



Production of Colo'urs in Double 

 Lights. 



See diffraction. 



Hooke on the colours of a bubble. Bircli. 

 III. 29. 



Newton on the colours of thin plates. Birch. 

 III. 247, 278. 



Lahire on the iris round candles. A. P. IX. 

 364. 



Langwith and Pemberton on supernume- 

 rary rainbows. Ph. tr. 1723. XXXII. 

 241, 245. 



Mairan on diffraction. A. P. 1738. 53. H. 

 82. 



Daval on an extraordinary rainbow. Ph. tr, 

 1749. XLVI. 193. 



Confirming Langwith's account. " Within the purple 

 of the common rainbow there were arches of the following 

 colours. 1. Yellowish green, darker green, purple, a. 

 Green, purple. 3. Green, purple." These colours were 

 not visible near the horizon, although the bow was very 

 bright there. 

 Boscovich on a halo near the sun. A. P. 



1754. H. S.2. 

 Mazeas on the colours produced by friction. 



A. Berl. 1752. 248. S. E. II. 26. 

 Euler on the colours of thin plates. A. Berl. 



1752. 262. 

 Due de Chaulnes on some experiments of 



Newton. Book 2, part 4. A. P. 1755. 136. 



H. 130. 



Gives an explanation, which is confuted by his ovm sug- 

 gestion, that the same eflect ought to be expected from a 

 lens as from a mirror. 

 N. C. Petr. VI. 420. 



Biilfinger saw in 1741 three supernumerary rainbows 

 within the primary one, the first red, the second blue, 

 green, and red, the third dark and red. There are also 

 three other similar observations. 



Dutour on coloured rings and on diffraction. 



S.E. IV. 285. V. 635. VI. 19. 

 Dutour on the phenomena of thin plates, 



flaws, and thick plates. Roz. I. 368. II. 1 1, 



349. V. 120, 230. VII. 330, 341. 

 Dutour on fringes of colours. Roz. VI. 135, 



412. 

 Delaval on the colours produced by metak. 



Ph.tr. 1765. 10. 

 Benvenuti de lumine. 4. Vienn. 1766. 



Boscovich's theory. 



Diequemaie. lloz. VIL 300. 



Observed a third iris beyond the second, as much weaker 

 than the second as the second was than the first, and at 

 the distance of its breadth, or at 1 of the distance of the 

 first from the second : the red was internal, as in the secon- 

 dary rainbow- 



Cockin on an extraordinary appearance in 

 amist.Ph.tr. 1780. 157. 



