DATING GUIDE TO DALLMEYER LENSES
    1881 30000-31000
1862 5000 1882 31000-33000
1863 6000 1883 33000-34000
1864 7000-8000 1884 34000-35000
1865 9000-11000 1885 36000-37000
1866 12000 1886 38000-40000
1867 13000 1887 41000
1868 14000-15000 1888 42000-43000
1869 16000-17000 1889 44000-46000
1870 18000 1890 47000-48000
1871 19000-20000 1891 49000-50000
1872 20000 1892 51000-52000
1873 21000 1893 52000-53000
1874 22000-23000 1894 54000
1875 23000-25000 1895 55000
1876 25000-26000 1896 56000
1877 26000-27000 1897 57000
1878 27000-28000 1898 58000
1879 28000-29000 1899 59000
1880 29000-30000 1900 60000-62000

 
 
ROSS BRASS LENS FLANGES
Flange No.
0
1
1a
2
2a
3
3a
Diameter
1-3/8"
1-1/2"
1- 5/8"
1-3/4"
1-7/8"
2"
2-3/8"
Flange No.
4
5
5a
6
7
8
9
Diameter
2-1/4"
2-1/2"
2-5/8"
2-3/4"
3"
3-1/4"
3-1/2"
Flange No.
10
11
12
13
14
15
16
Diameter
3-3/4"
4"
4-1/4"
4-1/2"
4-3/4"
5"
5-1/4"