Until the development of electronic computers after World War II computation was done by people with or without the aid of mechanical devices. Certain people were known for their remarkable gifts of mental calculation, and became famous. George Parker Bidder was initially exhibited commercially as a "calculating boy" by his stone mason father until Sir John Herschel took an interest in the boy and made sure that he had a good education. That this print was published when Bidder was 13 is a confirmation of his fame.
After receiving an education at the University of Edinburgh Bidder became a distinguished engineer. The caption to this engraving reads, "George Bidder, of Devonshire, Aet.13. Whose extraordinary power of Calculation developed itself without instruction & reached an unprecedented height before he attained his seventh year."