4.2 Years 1900-1909

Number of slide rules: 13.

The early K&E Mannheim slide rules began to compete with their European counterparts. Inverse, folded, and cubic scales began to become available on the European slide rules. Manufacturers appear to have experimented with a variety of standard scale arrangements this decade in search of more efficient computational power. See, for example, the Dietzgen rules with their special “B” scales (1762-B), as well as the inverse scales and “triplex” scale arrangements on the Kolesch slide rules. The “log-log” scales, invented nearly a century earlier, are re-introduced by K&E on their duplex models at the end of this decade.

Some notable technical developments: Zeplin first flight; Wright Brothers and Kitty Hawk flights; Einstein’s development of special and general relativity; Ford’s Model T automobile.

Year Maker Model
c.1900 K&E 4041
c.1900 K&E American
1900-1914 K&E 4054
c.1901 K&E 4041
1902-1912 Dietzgen 1765
1903 Faber 350
c.1904 Dietzgen 1762-B
c.1905 Dietzgen 1762-B
1905-1911 Kolesch 2574 Mannheim
1905-1911 Kolesch 2713 Stadia
1905-1911 Kolesch 2832 Triplex
1909 Stanley Fuller’s Calculator Model No. 1
1909-1914 K&E 4056