Reference numberMS/119/2/78
TitleLetter from Frederick Marow Eardley-Wilmot, Cape of Good Hope Observatory to Humphrey Lloyd, Trinity College, Dublin
Date26 March 1841
DescriptionEardley-Wilmot updates Lloyd on the proceedings at the Cape of Good Hope observatory. Eardley-Wilmot describes a series of ‘blunders and consequent loss of time’ since he last wrote to Lloyd. The horizontal force instrument was not ready in time and therefore could not be adjusted. The vibrating motions of the suspension make it difficult to adjust. The vertical force was adjusted but not permanently fixed. Eardley-Wilmot describes being confused by his observations but discovered there was an insect ‘perambulating’ on the bar which made them useless. Eardley-Wilmot moved the chronometer the wrong way, the result of which was that only 12 hours of declination were results that could be relied upon.

After the term day was over Eardley-Wilmot took the declination bar down and put up the suspension of a new silk sent by Lloyd, and the two large magnetometers were also adjusted.

Eardley-Wilmot discusses the vertical force instrument, and that he is unable to fix it perpendicular to the meridian and cannot make the needle balance on reverse.

Description of the building that houses the dip circle, a wooden hexagon, and its near completion.

Discussion regarding experiment for temperature, and declination changes.

Discussion regarding various instruments and their installation. The weather and its effects on the building and equipment. The collimation mark will be ready soon, and its description. Eardley-Wilmot had a meridian mark in a house but finds it useless it the winter season.

Discussion on the returns Eardley-Wilmot will be sending Lloyd at the end of the month, as well as what the term day observations showed, and intentions for the next term days. Means of finding the longitude. The vertical force instrument to be tried at different azimuth’s before being permanently fixed.

Eardley-Wilmot discusses making a portable instrument for vibrations, and the men he is working with.
Physical descriptionInk on paper
Access statusOpen
Fellows associated with this archive
NA6061Eardley-Wilmot; Frederick Marow (1812 - 1877)1812 - 1877
NA8252Lloyd; Humphrey (1800 - 1881)1800 - 1881
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