The Papers of Joseph Henry


Facsimile of Henry's "Record of Experiments" entry of March 27, 1847, Henry Papers, Smithsonian Archives.
Davy suggests that the greatest intensity of heat possible may be produced by the combination of the effect of the voltaic arc and the jet of the compound blow pipe[1]— This would merely produce a greater quantity of heat without increasing the intensity.
Dr Ure says the light of a flame may be increased while its heat is diminished.[2]
I was very much struck last night in going to bed to observe the candle in my hand surrounded with a series of perfectly distinct coloured circles—the perfect representation of Newtons rings.[3] My eyes were slightly inflamed and particularly the one with which the coulered rings were most distinctly seen. The inner &[A] more distinctly exhibited ring was about 4 inches in diameter the candle being about 15 inches from the eye. The order of colour was yellow Red blue Yellow Red Blue &c. The diameter of the rings increased as the candle was removed from the eye. The plane of the rings was perpendicular to the line joining the eye and the candle and continued to be so when the candle was moved. I have often seen colours around the candle when I have got up from bed in the night before washing my eyes but never so distinctly have the rings been exhibited as on the present occasion.
The effect is probably due to a film of mucus spread over the surface of the eye and may perhaps be imitated by dipping the finger into a Solution of sugar and applying this to the eye.
The order of succession is that of the transmitted light of Newtons rin[g]s.
Henry Papers, Smithsonian Archives.
    [1] Humphry Davy, "Some Researches on Flame," Phil. Trans., 1817, p. 74.
    [2] Andrew Ure (1778–1857) was a consulting chemist in London. DNB. We have not identified the source.
    [3] A reference to Sir Isaac Newton's discovery that various spectra in the form of circular rings are produced when light is either reflected from or transmitted through a thin film of varying thickness.
The order of the colors from reflected light differs from that due to transmitted light. David Brewster, A Treatise on Optics (London, 1831), pp. 102–103. See also Henry Papers, 3:390; 6:60.
    [A] Altered from or