TALBOT3394

British Museum
14^th Nov^r 1836

My dear Sir,

I have observed a most beautiful instance of circular polarisation in a salt discovered by my friend D^r Dowler, ¹ & not yet I believe made known to the world – He obtains it from urinary Calculi and calls it Xanthate of Ammonia – It seems to me peculiarly illustrative of your views, as the crystalline structure of the salt is very distinct, in masses nearly as large as a [illegible deletion] Pea, and presents the appearance of hemispheres, composed of spiculæ radiating from a common centre – I think You should examine this salt before the second part of your paper is read –

Ever my dear Sir, faithfully your’s
John Geo. Children

H F. Talbot Esq
&c &c &c