4.2 Years 1900-1909

Number of slide rules: 19.

The early K&E Mannheim slide rules began to compete with their European counterparts. Inverse, folded, and cubic scales began to become available as 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. Specialty slide rules, for example for electrical calculations (“electros”) and for chemical proportions, and so on, came on the scene. The “log-log” scales, invented nearly a century earlier, are re-introduced on the early electro rules in Europe and 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
1901 Scofield Engineer’s Slide Rule
1901-1904 Kolesch Mannheim
1902-1912 Dietzgen 1765
1903 Faber 350
1903 K&E 4054
1904 K&E 4041
1904-1905 Faber 367
c.1905 K&E 4035
c.1905 K&E 4041
1905-1907 Dietzgen MultiplexProto
1905-1911 Kolesch 2574 Mannheim
1905-1911 Kolesch 2713 Stadia
1905-1911 Kolesch 2832 Triplex
c.1907 Dietzgen 1762-B
c.1907 Dietzgen 1762-B
1907 K&E 4013 Thacher
1909 Stanley London Fuller’s Calculator Model No. 1
1909 The American Art Works Slide Rule for Concrete Slabs
1909-1914 K&E 4056