4.4 Years 1920-1929
Number of slide rules: 29.
The standard Reitz scale arrangement began to include a CI scale with the K and L, and these scales became more prevalent among many manufacturers. Also, scales for the efficient computation of hyperbolic functions of complex variables (vector scales) were invented at the end of the decade.
Some notable technical developments: first AM radio station, controlled nuclear experiments, development of quantum theory began, TV invented.
| Year | Maker | Model | |
|---|---|---|---|
| c.1920 | K&E | 4088-5 |
|
| c.1920 | Nestler | 1a |
|
| 1921 | Faber-Castell | 363 |
|
| 1921 | K&E | 4054 |
|
| 1922 | K&E | 4035 |
|
| 1922 | K&E | 4088-3 |
|
| 1922 | K&E | 4092-3 |
|
| 1922-24 | Nestler | 37 |
|
| 1923 | Faber-Castell | 379 |
|
| 1923 | K&E | 4088-3 |
|
| 1923 | K&E | 4088-1 |
|
| 1923 | K&E | 4092-5 |
|
| 1923 | K&E | 4092-3 |
|
| 1923 | K&E | 4092-3 |
|
| 1923 | Tavernier-Gravet | Mannheim |
|
| 1924 | KHH | Mannheim Multiphase Adjustable |
|
| 1925 | K&E | N4053-3 |
|
| 1925 | K&E | 4092-3 |
|
| c.1925 | Nestler | 41 Pocket |
|
| c.1925-1930 | KHH | Mannheim Multiphase Adjustable |
|
| 1925-1936 | K&E | 4058 |
|
| 1928 | K&E | N4053-3F |
|
| c.1928 | P.A.S. Co. | Engraving Rule |
|
| 1928-1933 | Nestler | 33 Chemiker |
|
| 1929 | K&E | Mystery2 |
|
| 1929 | K&E | 4092-3 |
|
| 1929 | K&E | 4092-3 |
|
| 1929 | Tavernier-Gravet | Beghin |
|
| 1929-1937 | K&E | 4058C |
|