
Brass demonstration polariscope with biaxial crystal
1830-1880
1830-1880
1865-1875
1870-1880
1850-1899 (estimated)
1840-1850
1850
1850-1924
1840-1850
1840-1850
1875-1880
1828-1830
1845-1855
1876
1850-1924
1850-1924
1962
1890-1900
1960
1825-1835
1830-1880