<choice xmlns="http://www.tei-c.org/ns/1.0"> <abbr>Obs.</abbr> <expan>Observation</expan> </choice> d’<choice xmlns="http://www.tei-c.org/ns/1.0"> <abbr>Incl.</abbr> <expan>Inclinaison</expan> </choice> <choice xmlns="http://www.tei-c.org/ns/1.0"> <abbr>magn.</abbr> <expan>magnétique</expan> </choice> à <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0009527 https://www.geonames.org/1489246">Troitzk</placeName> <lb xmlns="http://www.tei-c.org/ns/1.0" />le <date xmlns="http://www.tei-c.org/ns/1.0" when="1829-09-02" calendar="#julian">21 Août</date> matin 11<hi xmlns="http://www.tei-c.org/ns/1.0" rendition="#sup"><choice> <abbr>h</abbr> <expan>heures</expan> </choice> </hi> en plein <lb xmlns="http://www.tei-c.org/ns/1.0" />champ