Deaths on December 21

Friedrich August von Quenstedt, German geologist and palaeontologist (b. 1809)

Friedrich August von Quenstedt (July 10, 1809 – December 21, 1889), was a German geologist and palaeontologist.

8 Jan

Punched card
Herman Hollerith is issued US patent #395,791 for the 'Art of Applying Statistics' — his punched card calculator.
30 Jan

Mayerling Incident
Archduke Crown Prince Rudolf of Austria, heir to the Austro-Hungarian crown, is found dead with his mistress Baroness Mary Vetsera in the Mayerling.
23 Mar

Mirza Ghulam Ahmad
The Ahmadiyya Muslim Community is established by Mirza Ghulam Ahmad in Qadian, British India.
2 May

Treaty of Wuchale
Menelik II, Emperor of Ethiopia, signs the Treaty of Wuchale, giving Italy control over Eritrea.
6 May

Exposition Universelle (1889)
The Eiffel Tower is officially opened to the public at the Universal Exposition in Paris.