Dr Hanna <1> the Editor of the N. British Review <2> has just called upon me to say that he will be very glad to receive Profr Ray’s Review for the No which will be published on the 1st of May. It would be desirable to have it of a moderate length and as popular as possible for such a Review may be made a very readable one.
I beg to thank you for the Boracic Salt; but tho’ I have tried every variety of proportion between the Salt and the water I can get nothing like circular crystals. <3> I have again tried the Borax and Phosphoric Acid but in vain.
I enclose a small portion of the Lithoxanthate of Ammonia, which seldom fails.
I have preserved with great care the three drawings by Mr Curtis which you kindly gave me. One of them shews two & another three black rings close to the minute sectors of light in the Centre of the crystal, but not the external black ring. I have never seen more than one black ring where your drawings shew two & three. The boundary of the first of Newton's order of tints <4> often appears black with moderate magnifying powers, & it requires a high power and a fine microscope to detect its true nature. Your three black rings without any tints between them
are excepting the white, puzzle me greatly if they are really black.
By making your Boracic Salt in solution boil, it rises into foam, & when the bubbles are separate and smooth in their surface they give a black cross with 4 faint sectors, arising solely from Polarisation by refraction, as in the films of decomposed glass.
I was quite aware of the Expts on the liquefaction of gasses, but have never heard of a single observation on the fluids in Crystals. I will send you some specimens on my return from Rossie Priory <5> where I am going on a visit. I would have sent you them tonight, but I must select them by the Microscope and am particularly occupied.
Believe me to be Ever Most Truly yrs
St Leonards College
Decr 31st 1847
H.F. Talbot Esqr
1. William Hanna (1808–82).
2. At the time, a journal of the Free Church.
4. Newton’s rings.
5. Seat of the Kinnaird family, in the Carse of Gowrie, Perthshire, erected from 1807. Home of George William Fox Kinnaird, 9th Baron Kinnaird, 1st Baron Kinnaird of Rossie (1807-1878); scientist and land reformer.