1851
ID: 887
First submarine telegraph cable laid across English Channel
ID: 887
1851
ID: 888
Bernhard Riemann develops foundations of differential geometry for curved spaces
ID: 888
1851
ID: 889
Riemann develops theory of Riemann surfaces - multi-valued complex functions
ID: 889
1851
ID: 886
June 1851
Marx's illegitimate child born to maid Lenchen - Engels claims paternity to cover
ID: 886