Reference numberMS/119/2/84
TitleLetter from Frederick Marow Eardley-Wilmot, Cape of Good Hope Observatory to Humphrey Lloyd
Date3 September 1841
DescriptionEardley-Wilmot informs Lloyd that he has recently received his letters dated 14th May and 18th June and discusses his movement of the vertical force magnetometer a second time, now replacing it to the position of the magnetic meridian. The negation sign indicates that the roles of the horizontal force and the vertical force should be in opposite directions.

Eardley-Wilmot had to repeat the intensity measurement due to an unusual disturbance of the declination bar.

Eardley-Wilmot recounts the events of a dangerous accident to one of Mr [Thomas] Maclear’s daughters, and the injuries she sustained. Eardley-Wilmot’s informs Lloyd she is out of immediate danger and asks him not to mention this to anyone yet. This accounts for the lack of observations for three days.

Discussion on the dip. Eardley-Wilmot requests Lloyd for his remarks on the differences in the dip, though the mean remains nearly the same. Eardley-Wilmot is now realising that he may be able to conduct the absolute measurement himself at the same time, by using bars whose time of vibration was slightly different, so that he is able to go from one to the other. The same method can be adopted with the deflection and vibration, being conducted at the same time through the two buildings. Discussion on vibrating the commencing arc.

Eardley-Wilmot is conducting a set of temperature experiments for the vertical force and hopes to complete them soon. Discussion on the strange behaviour of the vertical force magnetometer. The term day was singular at the Cape of Good Hope observatory, and Eardley-Wilmot would like to see an account of Lloyd’s term day.

Mr Maclear’s child is now nearly recovered. Eardley-Wilmot has not heard from [John Henry] Lefroy for more than three months, Major Michel has returned after a year away.

Lord Derby has employed ‘three whites and 2 [?] traveling in the interior in hopes of meeting with Major Harris Black antelope, the Boer sent a commander after them, and they very nearly had to fight for it, but luckily they convinced them they were not spies’.
Physical descriptionInk on paper
Access statusOpen
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