Public Domain Mark
You can use this work for any purpose without restriction under copyright law. Read more about this licence.
Credit
On a disturbance of the earth's magnetism : in connexion with the appearance of an aurora borealis, as observed at Albany, April 19, 1831 / by Joseph Henry. Public Domain Mark. Source: Wellcome Collection.
Provider
This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)