|Title||Unpublished letter, regarding magnetic variation in Cape Horn from John Macdonald to Sir Humphry Davy|
|Date||18 January 1827|
|Description||Macdonald 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]'.
Written by Macdonald in at Lady Chambers', Richmond [London]. Received by the Royal Society on 19 January 1827 from Davy.
|Physical description||Ink on paper|
|Related records in the catalogue||AP/12/15|
Fellows associated with this archive
|NA8200||Davy; Sir; Humphry (1778 - 1829); chemist||1778 - 1829|
|NA3036||Macdonald; John (1759 - 1831)||1759 - 1831|