TALBOT3855

S^t Andrews
April 7^th 1839

Dear Sir,

I am much obliged to you for the new specimens of Photogenic Etching ¹ which have excited great interest here, and for the leaf of the Comptes Rendus. ²

I have tried in vain to make the Circular Crystals; ³ and I must beg you to favour me with one of your own specimens, as I think I can do something on the subject.

I have discovered the Ghost of Circular Crystals under very curious circumstances. I read or rather Spoke a notice on the subject at the last meeting of our Society here, ⁴ of which I will send you an account in the Fifeshire Journal which is published on Wednesday last. You will scarcely believe it possible that a Black Cross with coloured luminous Sides exactly like the phenomenon of circular Crystals can be produced by a substance without a trace of crystallisation.

I find the Circular Crystals of the Litho-xanthate of Ammonia ⁵ very easily made, and have got some rather interesting results with them. I shall return your N^o of the Comptes Rendus under M^r Strangways ⁶ Cover as you direct,

and I am Dear Sir
Ever Most Truly yrs

D Brewster

H.F. Talbot Esq^r