Figure 1. Du Bois D. Parmelee's key-driven adding machine (1850). The keys are numbered from 1 to 9 and have increasing heights. Typing on a key raises a graduated rule which then represents the sum of the keyed digits. This drawing is excerpted from the patent application; no copy of the machine is known.
Figure 1.

Du Bois D. Parmelee's key-driven adding machine (1850). The keys are numbered from 1 to 9 and have increasing heights. Typing on a key raises a graduated rule which then represents the sum of the keyed digits. This drawing is excerpted from the patent application;3 no copy of the machine is known.

Additional Information

ISSN
1934-1547
Print ISSN
1058-6180
Pages
59-65
Launched on MUSE
2008-03-31
Open Access
No
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