Optician more important and dignified. Far-sighted or aging colonial Americans imported spectacles from Europe. Spectacles were primarily for the affluent and literate colonists, who required a valuable and precious appliance. Benjamin Franklin in the 1780s developed the bifocal. Bifocal lenses advanced little in the first half of the 19th century. The terms bifocal and trifocal were introduced in London by John Isaac Hawkins, whose trifocals were patented in 1827. In 1884 B. M. Hanna was granted patents on two forms of bifocals which become commercially standardized as the "cemented" and "perfection" bifocals. Both had the serious faults of ugly appearance, fragility,
Benjamin Franklin Sermon", also known as "The Way to Wealth". Franklin's autobiography, begun in 1771 but published after his death, has become one of the classics of the genre. Daylight saving time (DST) is often erroneously attributed to a 1784 satire that Franklin published anonymously. Modern DST was first proposed by George Vernon Hudson in 1895. Franklin was a prodigious inventor. Among his many creations were the lightning rod, glass harmonica (a glass instrument, not to be confused with the metal harmonica), Franklin stove, bifocal glasses and the flexible urinary catheter. Franklin never patented his inventions; in his autobiography he wrote, "...