Sir H. Thompson dined with me at R.S. anniversary dinner.
Dr Dyson made an observation of the Sun’s Transit across two plumb lines to determine the Meridian line of the New Altazimuth. The result agreed closely with the line obtained by Mr Nash by Magnetic Observations. The two plumb lines were 37ft apart. The Centre of the Sun & the second limb crossed the line 5s too soon: giving an error of 2s. Mr Nash’s line was compared with Col: Tupman’s & agreed well.