Dr Joseph Fry opened his chocolate company in the mid-1700s, marketing the powder for medicinal purposes, but it was his grandson, Joseph Storrs-Fry, who achieved the historic breakthrough. Combining Van Houten’s pressing machine with the Watt steam engine, he began mass-producing cocoa cakes and experimenting with the mix of butter and flavourings to produce something they could mould into shapes. By 1847, Fry had the balance..just right, and began selling..the world’s first chocolate bars.
from Dictatorland, The Men Who Stole Africa, by Paul Kenyon (2018). Very Highly Recommended.