Magnetical instructions for the use of portable instruments adapted for magnetical suverys and portable observatories, and for the use of a set of small instruments adapted for a fixed magnetical observatory;

Mode of access: Internet.

Researches.

Mode of access: Internet.

Terrestrial magnetism. Alaska magnetic tables and magnetic charts for 1920,

Running title: Alaska magnetic tables and charts, 1920.

Magnetical observations in the Arctic seas.

Mode of access: Internet.

Handbuch des Erdmagnetismus.

Mode of access: Internet.