' Inquiries into Coloured Light, 45 



I bf jiah in examinins; coloured lights by that of red-hot iron *, 

 This viewed throiioh a prifni decompofed into a dcepiv 

 tinged red, and a deep blueiili green only; the gradations of 

 blue, if thev are not abforbcd in the deep green, are To ra- 

 pidly ablbrbed in darknefs as to be hardly if at all vilihie. 



I had read in Lavoillcr of a red light, but was not able to 

 afcertain the fact: fome time after, I met with a pallage 

 in a tranflated edition of Lavoiiicr, inferlcd by the editor, 

 wherein he mentions an cxaiiiple of a red ligiit produeed by 

 the vapour of (trontian inflaniLd hy fpirits of wine, and re- 

 prefents it of a deep blood colo'ar. In trials which I had an 

 opportiinitv of feeing, and of making niyfelf, this light, which, 

 mixed with the inflamed vapour, ap|X'ared to niv eve to give 

 out a light hv intermitting flaOies tinged with rather a car- 

 mine red; and I karn that, nitrate of ilrontian gives to, the 

 flame of fpirit of wine a bright carmine red. Dr. Git)bes'^ 

 Ihowcd me anoiher iufiance ol muriate of (trontian giving a 

 luftiifion of red to the flame of I'pirit of wine. Nitrate vi 

 iime, formed into the fait called Baldwin's pholphoru?, doe*^ 

 the fame, 



I am taught that nitre, diftillcd with half its weight of ful- 

 phur, eives a Vf/Aii^ J acid liquor yielding red fuvus. 



Hydrogen and carbon, united with oxygen in the con- 

 fiituent parts of animals and with azote in vegetables, 

 form oil and fat : the flame of thefe is yellow or yel- 

 lowid), as the flame of fuiphuric and bituminous bodies is 

 blue fufiufed \sith green ; the vellow of the -fcrnier runs into 

 rcddifli fumes, the blue of the latter into greenilh fumes, 

 'i he oleaginous parts of bitumens being vellow, explains the 

 reafon why their blue flame is difpofed to green. Wrdcgris 

 inflamed with fpirit of wine gives out a green flame ; but 

 this deconipofcs into a red and blue, with an intermediate 

 blue-green. 



Although thefe coloured flames and vapours arc not ho- 

 mogeneous, yet thev obferve, according to various attra«ilions 

 which the aeriform fubftanccs, their refpeiSlive bales, are lia- 

 ble to, the fame laws of rcfra6ti(jn and decompofition as the 

 folar ligbl doih, the primary colours of which are not thcin- 

 felves homogeneous. 



• Although ihtrc it no decided Haire in this cale,- yet whoevt-r vitws 

 a piece of red-hot iron alonp iis fides will fee a waving tremulous v^j;oiir. 



f I bejj here to acknowledge il.r obligations I received from D''- Gibli'.v, 

 in tliL' airrfii^^cnicnts of any niattet^ connedled wiili cheniiltry whicU 1 had 

 wccafion ro refer 10. 



J it ma^ be worth noticing, by the by, that a? tbi» yellow liquor gi^^efj 

 in Its aciitorni flaie, a red funic j folulphur, yeiiovv la at lolid fviiii, gives 

 «uc, in *t% aeriform liatc, a blue iian e- 



A« 



