Reference numberAP/12/15/5
TitleUnpublished letter, regarding magnetic variation in Cape Horn from John Macdonald to Sir Humphry Davy
Date18 January 1827
DescriptionMacdonald writes about an east variation of the magnetic needle observed near Cape Horn [Tierra del Fuego, Chile] on its west, south, and east sides, which he believes is caused by the local attraction of magnetic strata. Includes a figure illustrating this phenomenon.

John Frederick William Herschel's initials appear in graphite next to the date received. An ink inscription at top of first page reads 'N. T.Y. [Thomas Young]'.

Subject: Geodesy

Written by Macdonald in at Lady Chambers', Richmond [London]. Received by the Royal Society on 19 January 1827 from Davy.
Physical descriptionInk on paper
Access statusOpen
Related records in the catalogueAP/12/15
Fellows associated with this archive
NA8200Davy; Sir; Humphry (1778 - 1829); chemist1778 - 1829
NA3036Macdonald; John (1759 - 1831)1759 - 1831
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