CATALOGUE. NATURE OF LIGHT. 



321 



■^ 



Delavalon the colours of opaque bodies. 4. 



R. S. 

 Delaval on the permanent colours of opaque 



bodies. Manch. M. II. 131. 



Maintains, that all light is reflected by white particles, and 

 coloured in its transmission. No transparent coloured me- 

 dium reflects any light when examined within a blackened 

 bottle; this isthown by experimenls on Q8 kinds of fluids 

 and on many kinds of glasses. Vegetable extracts also appear- 

 ed black, earth being the only reflective substance in vege- 

 tables. Fibrous animal substances are while, the extractive 

 juices black. Supposes that coloured metals consist of 

 ycHow transparent matter mixed nyith white reflective par- 

 ticles. Glass tinged mth a little arsenic is yellow or orange 

 by transmitted, and blue by reflected light, like the atmo- 

 sphere : for this, and for the colours of the sea Mr. Delaval 

 proposes a very improbable theory. It appears that bodies 

 acquire this property as they lose their transparency : thus 

 glass tinged.with gold and rendered opaque by heat transmits 

 violet light, and appears by reflection brown. Infusions of 

 woods, used in dying red, transmit yellow or red light ac- 

 cording to their thickness. Sap green digested in alcohol 

 transmits green light when thin, dull yellow and then bright 

 red when thicker : other vegetable greens have the same 

 property, and the aqueous infusion in some degree. Infu- 

 sion of litmus appears to be blue when thin, then purple, 

 and when still thicker, bright red. Mr. Delaval supposes 

 that these colours are produced by inflection : the colours 

 of thin plates, he says, are produced by the reflection of 

 light from their posterior surfaces. 



Higgins on hght. 8. Lond. 177(i. R. I. 

 On colours. Roz. X. 66. 

 Arena Physicae quaestiones. 4. Rom. 1777,. 

 Sentbier sur I'influence de la lumicrc solaire 



pour modifier les etres des trois regnes de 



la nature. 3 v. 8. Gcnev. 1782. 

 Senebier on light, in answer to Marivetz. 



Roz. XXV. 74. 

 Sentbier on the effect of light in bleaching 



wax. M. Laus. III. 362. 

 Senebier on the effect of light in bleaching. 



Roz. XXXVin. 56. 

 Answer to Senebier's remarks on light. Roz. 



XIII. Suppl. 281. 



VOi. II. 



Bonnet on the effects of light upon colours. 

 Roz. XIII. 462. 



Wilson's proposed experiment on the aberra- 

 tion of the fixed stars. Ph. tr. 1783. 38. 



Fontana on light. Soc. Ital. I. 104. Crell. 

 Chem. ann. 1784. 



Fontana on the path of light during refrac- 

 tion. Soc. Ital. III. 498. 



Marat sur la lumi^re. 



Marivetz on the propagation of light in an 

 elastic medium. Roz. XXIII. 340. XXIV. 

 40, 230, 275. In answer to Senebier. Roz. 

 XXVI. 140." 



Remarks on Marivetz. Roz. XXIII. 380. 



Ph. tr. 1784. 35. 



Michel observes, that the attraction of large stars should 



produce a difference in the velocity of light. 



fBowdoin on the nature and waste of light. 

 Am. Ac. I. 187,208. 



Supposes a solid orb to surround the whole universe and 

 to preserve the light emitted from the sun and stars. 



Experiments and observations on light and 

 colours. 8. Lond. 1786. 



Suggests, that light constitutes a scale of rays extending 

 considerably on each side of the spectrum, the rq^ddle part 

 only being visible to us : but forms no conjecture respecting 

 the nature of the extremes. 



Berthollet on the influence of light. Roz. 

 XXIX, 81. 



Chaptal on the effect of light in crystalliza- 

 tion. Roz. XXXIII. 297. 

 . Deluc on light and heat. Roz. XXXVII. 

 54, 116. 



Comparetti de luceet coloribus. 



Saussure on the chemical effects of light. M. 

 Tur. 1788. IV. 441. " ■ 



Finds the effect increased on a high mountain. 



Dorthes on the effects of light. Ann. Ch. II. 



92. 

 Robison on the motion of refracting mediums, 



Ed. tr. II. 83. 



Corrects the errors of Boscovich. 

 T t 



