Anne Robinson, Karen Saxby
With 48 fact-filled cards per package, Knowledge Cards are a great source of condensed information—all in a deck the size of a pack of playing cards. Mysteries of the parking meter laid bare! Adding to the satisfaction of reading about the often peculiar circumstances from which forty-eight machines, substances, or technologies arose, this deck reproduces the drawings (mostly in cross section) that accompanied their patent application. Some of the drawings are more entertaining than they are comprehensible, but most—the first disc brake (1902), can opener (1870), washing machine (1910), automatic car wash (1962), and safety pin (1849), for example—are as clear as so many bells.