A Rare Circular Slide Rule Calculator by Palmer and Fuller. 1847.

This is a double-sided circular slide rule calculator consisting of concentric moveable circles made in 1847. A lithograph engraving, by George G. Smith from Boston, mounted on heavy cardboard, containing 'Fuller's Time Telegraph' on one side and 'Palmer's Computing Scale' on the other. The Time Telegraph was used to calculate time lapse in days or weeks between any two given dates. Designed by John Emory Fuller (1799-1878) in 1844 and patented in 1845. The title probably reflected the fascination with the new high-speed telegraphic technology (Morse telegraph, 1844), implying high speed in calculation. 'Palmer's Computing Scale' was used to calculate square measures, cubic measures, timber measures, grain measures, liquid measures and interest rates from 3 percent to 10 percent on a daily and monthly basis. Invented by Aaron Palmer and patented in 1843 in Massachusetts, the copyright of which had been purchased by Fuller in 1844 or 1845. This 'computing scale' represents a very early use of the word 'computer' for a device rather than a person. Until the invention of electronic computers in 1945 the term 'computer' usually referred to a person who compiled mathematical tables with or without assistance. The slide rule dimension is 28x28x.5 cm.