TALBOT3498

My Dear Sir,

I am this moment favoured with your letter, ¹ and am delighted to hear of your troublesome Spectrum which must be something interesting. I have been hard at work on the subject of absorption, and have been fortunate in discovering a fact which proves the connecting link between the phenomena of Interference and those of Absorption. This overturns many favourite views of my own on the subject of absorption as a primary principle, and generalises the views of Newton ² respecting the colours of Natural bodies. – There are many difficulties, however, to be overcome in establishing his theory, & in explaining the total disappearance of one of the complementary tints; and when this is done the theory necessarily requires a considerable modification.

I do not know if I mentioned to you that I have been engaged in drawing up Memoirs of the Life & Writings of Sir Isaac Newton ³ on a large scale. I have been most kindly promised the use of the Newton MSS in the possession of the Earl of Portsmouth, by M^r Fellowes, and I have engaged to meet him at Hurstbourne Park ⁴ on the 10^th of May to inspect this valuable Collection of Papers. I am therefore most anxious to establish & extend the Newtonian Theory of the colours of Natural bodies, ⁵ and the more so as I have been one of the Ringleaders in the assault which has been made upon it. ⁶

I expect to be about a week in London either on my way to Hurstbourne, or on my return from it, and I look forward with much pleasure to the chance of seeing you.

I am at present drawing up a Treatise on Optics on a large scale for the Encyclopædia Britannica, and as I am anxious to give a full account of recent investigations you would oblige me much if you could give me a memorandum of your various papers and discoveries that I may not commit any [illegible] this omission, which I should run a risk of doing without such an Index.

I have been able to observe the complementary reflected tints in various coloured minerals, or Apical coloured glasses and fluids; but I have failed today in an elaborate attempt to make this observation on the Ammonuret of Copper, in Sulphur, & Sulphate of copper. I wish you try your skill in such an experiment.– What a Spring this has been! It is now snowing as if it were mid Winter, & there is no prospect of getting the Seed into the Ground.

I am My Dear Sir Ever Most Faithfully y^rs
D Brewster

Allerly by Melrose
April 12^th 1837

H.F. Talbot Esq^r