Castle Parsonstown
February 2d 1854
Dear Talbot
We have recently made some attempts here to Photograph the Moon but with little success. With Thomas’s Collodion <1> our 3 feet speculum gave a tolerably strong impression in 25”, but during so long an exposure the variations of the air were considerable and there was no sharp definition.
The experiment was made with the telescope fixed, and the plate moved by the clock. The slide containing the plate was adjusted to the Moons apparent motion by a micrometer eye piece, with a line in it truly parallel to the slide. The adjustment was easy and accurate. The clock was on the usual principle of smooth motion clocks except that the balls of the conical pendulum were counterpoised, so that the action of gravity was neutralized, springs having substituted for gravity: the rota of the clock was therefore not altered by position. The performance of the clock was satisfactory, but the screw to move the slide had been hastily made, and we have cut a fresh one with our Whitworth lathe which will be true within very narrow limits. Arrangements are nearly complete for applying the same machinery to the six feet speculum. I do not however expect that we shall obtain any Photographs of the least Scientific value unless the time of exposure can be greatly shortened, the undulations of the air will interfere so much, but I have hopes from your instantaneous process. When in London I enquired from Mr Thomas whether he had tried it, but I found he had not and I have not discovered any person who has.
In a few days I hope to have an opportunity of making the attempt, and if there are any hints you can give me in addition to what you have published I shall feel much obliged.
Lady Rosse has just commenced Photography, and I enclose a few specimens of her first attempts, presently she will do better
Believe me to be vy try yrs
Rosse
[envelope:]
Fox Talbot Esqr
Laycock Abbey
Chippenham
England
Notes:
1. R.W. Thomas (d. 1881) was an active photographic chemist and one of the first to market collodion solutions to amateurs and professionals, under the trade name of ‘Xylodine’. For many years after 1851 he had a well-deserved near monopoly on this commodity.