Demainbray's convex lens
1750
1750
1720
circa 1750
1742
2000-100 BCE
1705-1737
1717-1725
1725
1712-1713
1735-1745
1720
1745
1730
1990-96
1717
1720-1730
1714
4000-2001 BCE
1725
1725
1730-1750
1725
10000-5000 BCE
1910-130
1730-1736
1740
1713
1744
1712
1736-1740
1740
1710-1747
1713-1750
1710-1720
1750
1738
1730
1745
1730
1714
1737-1738
1750
1743
1737
1720
1732
1747
1750
1740
1750