Archive of Collections

Details and Image

TypeModel No.MakerCountryConstruction
DateScale LengthArea of Use
Hemmi / 2664 Rietz
Celluloid over bamboo
25 cm
Engineering and business

Notes: "This is a pre-1950 Hemmi model 2664 slide rule with a scale set that would be called a Rietz, or almost a Rietz. I have seen this model referred to as a business slide rule, probably because of the CF and DF scales. However, with four trig scales that give tangents from 6 degrees to 76 degrees, and sines from 35 minutes of arc to 90 degrees note that to three significant digits, i.e., slide rule accuracy, the sine scale for 35 minutes to 6 degrees is also a tangent scale it is quite a useful engineering slide rule. Curiously the A and L scales share the space of one scale, with the left half being the A scale and the right half being the L scale. Later models (post-1949) featured full-length A and L scales, but lost the small-angle sine scale. "

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