Llandaff.
Tuesday. Decr 6.
My dear Father.
It is no good sending to Gillespie for a geometrical demonstration of the confocal quadrilaterals diagonals. What he was talking about was entirely analytical. The theorem you mention is Brianchons Theorem <1> – Pascal’s <2> being “The three intersections of the opposite sides of any hexagon inscribed in a conic section are in one s straight line. I have not yet found a proof of them. The letter copying answers so poorly that I am afraid I shall have to give it up.
I have changed the address of the Photographic Journal – If you wish for to have it I can send it on to you. I think after the year is ended I shall have it straight from the office & get a stamped copy. I am glad you think well of the Wothlytype <3> but it is disappointing fi to find that it has no trace of silver in it after all. As you think it would be a good thing for me to join the Junr University Club I shall write and ask somebody to put me up. Champneys has not been able to get the rules, but I believe they differ but little in different clubs. The entrance fee was 15 guineas when he for the original members but has been raised & he thinks it is something between 15 & 25. The subscription is 5 guineas. Why should one not have ones name put down for the Athenæum <4> for then if in 9 or 18 years you are a person of great eminence you get in & if you are not a person of great eminence you do not & there is an end of the matter? I have been doing a little mathematics lately – & now see how to project a rectangle into a quadrilateral with converging sides. I hope to send you some results soon. I had a letter from Bagwell <5> the other day proposing to come to Lacock on his way to Ireland for a few days if I were there. He proposes to cross the sea on the 23rd. So I wrote to say that unfortunately all the Family except you were gone to Edinburgh, but that as Mr Prichard <6> will be away for a day or two at Xmas, and if he liked to come for a few days inclose including Xmas I might go down there and we could have one days pheasant shooting at any rate & some rabbit shooting. I have not yet had his answer. He wrote me a most facetious letter in rhyming verse. He is reading law & find it dry. Our weather here is far too hot for the season so that fires are a bore –
Your affect son
Charles.
[envelope]
H Fox Talbot Esq
Lacock Abbey
Chippenham
Notes:
1. The dual of Pascal’s Mystic Hexagram theorem.
2. Blaise Pascal (1623–1662), mathematician.
3. The uranium-based printing-out paper invented by Jacob Wothly of Aachen, 1864, initally created quite a stir. It was considerably more sensitive than the albumen paper then in general use, but the claim for permanence was not fulfilled, and it was soon abandoned. [See Doc. No: 05220 and Doc. No: 08887].
4. The Athenæum and (London) Literary Chronicle, London.
5. A friend of Charles from University.
6. John Prichard, Welsh architect; Charles Henry Talbot apprenticed to.