
Cooke and Wheatstone's four needle telegraph, 1838
1838
1838
1835
1838
1836
1840
1842
1837
1837
1837
circa 1840
1839
1843
1841
1837
1839
1838
1835
1837
1834
1834
1834
1842
1955; 1830
1842
1842
1840
1841
1893-4
1934
1837
1840
1837
2000-100 BCE
1833
1863-7
1842
1841
1838
1837-1840
1839
1772 (original); 1919 (model)
1839
1839
1839
1990-96
1840
1801-1840 (original); 1901 (model)
1830 (original); 1967 (model)
1839 (original); circa 1988 (replica)
1833