1820
ID: 732
Hans Christian Oersted discovers electromagnetic induction
ID: 732
1820
ID: 735
Oersted discovers electromagnetism using mathematical analysis - new field requiring advanced math
ID: 735
1820
ID: 736
Cauchy develops systematic theory of residues in complex analysis
ID: 736
1820
ID: 737
Foreign diplomats report Russian military colonies as military prisons - economic costs exceed traditional army
ID: 737
1820
ID: 738
St. Catherine Laboure born - future visionary of Miraculous Medal
ID: 738
1820
ID: 739
Blessed Anne Catherine Emmerich has visions of Christ's Passion - My Church seems destroyed but will rise
ID: 739
1820
ID: 4463
Charles Xavier Thomas patents Arithmometer - first commercially successful mechanical calculator, 1,500 sold by 1878
ID: 4463
1820
ID: 5784
Chapman owns 1,200 acres of nurseries - not just folk hero but successful businessman, sells trees to settlers
ID: 5784
1820
ID: 733
July 1, 1820
Neapolitan Revolution begins - Morelli and Silvati march on Nola, start Carbonari revolution
ID: 733
1820
ID: 734
July 13, 1820
King Ferdinand I takes oath to Spanish constitution - Carbonari's spectacular achievement
ID: 734
1820
ID: 731
November 1820
Friedrich Engels born in Barmen, Germany - deeply pious town, conservative manufacturer father
ID: 731