Thanks WW for the University information. RS has put pressure on Troughton and Simms to send the 'top' as soon as possible. An update on RS's horse riding lessons. He ought to find a way of repaying the £100 he owes WW. RS 'had got a clumsy scheme in my head of supporting an invariable pendulum not by knife edges but upon a well ground steel cylinder said cylinder resting upon capital friction wheels...I am however inclined to suspect that the work of such friction wheels would be very expensive and their action a little uncertain'. A pendulum 'with a spring and with the clips invariably united to the spring would be more invariable than knife edges and Troughton [Edward Troughton] says that is the way he always asserted the experiment should be made'.
RS is too ill to be examiner at Cambridge. He is glad WW cannot stand for the Lucasian professorship: 'The Heads I dare say have made up their minds so that your chance would have been small...I should have felt sorry if you had tried and failed in obtaining anything else. Besides the ladies'. Edward Troughton 'has forgotten all he knew of clocks, springs etc and though he may talk about them will not of course think much now. I fear the springs but the experiment might be worth trying, only, don't expect any light from anybody as nobody knows anything about it except that it goes by a spring'. RS understands that the intended advantage of Hardy's work in the first scapement is to make the moving force constant. He got the following information from Molyneux concerning the pendulum: 'The compensation for heat and cold is contained of course in the pendulum for long and short arcs in the irregularity in the moving force in the spring at the top of the pendulum. Now the difficulties he apprehends are from the thickening of the oil upon the pallets. When the oil thickens from age the vibrations are of course smaller and then if the vibrations in long or short arise are not correct the clock may gain or lose according as the spring at the top is too tender (I fancy) or too stiff...The pendulum and its compensation are relied upon I believe to supply all occasional defects and Troughton swears that a perfect pendulum won't go well that he has made such but that the clocks went no better perhaps more with them'.
WW showed great foresight in sending AS the screw: 'He [Edward Troughton] must see and make me some others which will do the business completely'. AS gives news and suggestions concerning the parts made and under construction for the new Cambridge Observatory. He 'gave Troughton [Edward Troughton] my Woodhouse ['Physical Astronomy', 1818] and I was going to beg you to send me another but it need not as I shall probably soon be with you. I think our matters are coming to a close'.
RS gives various comments concerning faulty aspects of their respective barometers and the Cambridge telescope: 'I find I shall want a second quicksilver horizon on account of the telescope not being in the same vertical plane so that one cannot serve for the purpose I wish to try. I consulted [Edward] Troughton about the slits for the mural. He says he does not like to cut the building quite in two but he does not see any serious objection to doing so'. RS describes how he would pursue this plan (with a diagram). He has spoken to Troughton with regard to correcting for the expansion and contraction of the brass scale (on the barometer) when the temperatures at the upper and lower station are different. He gives the mathematical operation which makes this correction. Since writing the above he has seen Troughton who says he is 'against cutting the slits to the ground and would even prefer the raising the reflecting surface from the floor. This indeed might be easily done by having a little square pier thus [diagram] in front of the wall detached from it and covered by the floor. A stool which adjusted in altitude like a music stool might be placed upon it and thus take in all stars you wanted. Would not after all this be the cheapest and best way'.
RS cannot give any information as yet about lithography. WW's 'barometer only pretends to be comparative and is adjusted by another which is positioned to give yourself no uneasiness upon that head. The Galvanic plates look ugly enough to be very scientific but you know best what use you intend to extract from them. As the barometer and thermometer both require care they must stay here until I can bring them down which will be also as well for the Plates. What day this will be I am not quite certain but I hope on Thursday morning to mount the telegraph'. RS has sent and addressed his circle to WW and it should arrive at Shepherd's Bridge Street on Friday morning. He will bring his own barometer so that WW can compare it with his. Donkin [Bryan Donkin] has finished the Zenith Sector. RS hopes the observatory [Cambridge Observatory] 'may get so far advanced that to recede or limit the plan may be impossible even for the heads'. RS has been testing his instrument: 'Two lines of observations nearly contemporaneous gave me the same error in the chronometer within a second of time but that only proves that the instrument gives the same results and that the fault was not in the observer making the contacts'. RS gives Troughton's [Edward Troughton] answers to George Peacock's questions concerning the Transit.