4.3 Years 1910-1919

Number of slide rules: 30.

Variations in scale arrangements continued. See, for example, Dietzgen’s 1759-B with its R scale. Metal slide rules made their entrance in the U.S. during this decade as well. The Reitz scale arrangement was developed in Germany, which included K and L scales on the front with trig scales on the back of the slide. The K&E duplex models that include log-log scales for advanced calculations begin to gain popularity during this decade.

Some notable technical developments: air conditioning invented; World War I; nucleus of atom discovered.

Year	Maker	Model
c.1910	K&E	4041
1910-1912	Dietzgen	1761-AL
1910-1914	K&E	4053-2
1910-1914	K&E	4053-3
1910-1921	Dietzgen	1760-B
c.1912	Richardson	Direct Reading (812)
c.1912	Richardson	Pantocrat 812
c.1912	Richardson	1776
c.1912	Richardson	Direct Reading Pocket
c.1912	Richardson	Direct Reading Pocket
1913	Dennert & Pape	No. 9
1913	K&E	4092
1913-1914	Faber-Castell	378
1913-1914	K&E	4133
1913-1915	K&E	4100
c.1915	K&E	4058
1915	K&E	4071
c.1916	K&E	4058
c.1916	K&E	4083
1916-1920	K&E	4088-2
1916-1922	K&E	4088-3
1916-1925	K&E	4058 (student)
1917-1918	Richardson	Model of 1917
c.1918	Halden	Calculex
1919	Gilson	Midget
1919	K&E	4041
1919	KHH	Pocket Rule
1919-1927	Dietzgen	1759-B
1919-1927	Dietzgen	1759-B
1919-1927	Dietzgen	1759-B