Pièce 60 - Letter from Richard Sheepshanks

4 pp.

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.