TALBOT6265

Dear Sir,

I received your kind note just as I was about to leave Birmingham ¹, and it w^d have given me the greatest pleasure to have paid you a visit, had I not felt it necessary to hurry homeward in consequence of the prevalence of Cholera in this place, which prevented me also from paying some interesting visits on my way Northward.

I read a slight notice of my Exp^ts on Circular Crystals ² on Tuesday last at Birmingham. I of course mentioned your previous discoveries, and I exhibited the three beautiful drawings of circular crystals, ³ – or rather of their polarising structure, by Curtis which you were so good as to present to me.

I have been for some time occupied in perfecting a Chromatic Stereoscope as noticed in the Association Report for 1848, ⁴ in which distance, and consequence solidity, is given by colour alone without form. The binocular effect is produced by the edges of Lenses, as in the Stereoscope described in the Accompanying Paper. ⁵ In order to increase the effect I use lenses of highly dispersing Flint Glass, and of Oil of Cassia. With kindest regards to M^rs Talbot ⁶

I am Dear Sir Ever Most Truly yrs
D Brewster

S^t Andrews
Sep^tr 22^d 1849