
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1919
1920 - 2007
circa 1920
1920
1918
1918
1955; 1830
1918
1918
1921
1934
1921
1920
2000-100 BCE
circa 1920
1922
1920
1920
1920
1920
1903 (original); 1982 (model)
1772 (original); 1919 (model)
1990-96
circa 1920
1830 (original); 1967 (model)
1952-3
circa 1920
1839 (original); circa 1988 (replica)
1930 (replica); 1834 (original)
1919
1801-1892 (prepared); 1946 (element replaced)
1918
1920-1922
1921
1922
1934
circa 1919
1918-1920
4000-2001 BCE
1922
1918 - 2000
1925; 1862
1921
1921
1919
1834-1836
1940-03
1942-09
1942-07