INVENTIONS EXPLAINED

Platt (Stephen Biesty's Incredible Explosions, 1996, etc.) doesn't really explain inventions here, as David Macaulay did in The Way Things Work (1988); rather, he makes note of them and their time frame and how they benefitted humans. The structure of the book is chronological, starting with early tools and the use of fire and proceeding to, with many stops between, the X-30 spaceplane. The strength of the book is the way it conveys the global nature of inventions—from Chinese gunpowder to Peruvian reed boats, Persian windmills, and African bellows—and how they fit snuggly with the requirements of the places in which they were created. There are weaknesses here, too: Musical instruments never appear, discoveries are confused with inventions (DNA is included), and much is left unexplained—how does the astrolabe work, why did Gramme's dynamo stay cool and generate constant current, what is silk? Worse is the relentlessly upbeat narrative: ``Today scientists and engineers . . . create smart new machines which make our lives better,'' Platt chirps, with no cautionary notes—the genetic engineering of plants goes uncontested, livestock farms warrant ungarnished accolades. (diagrams, chronology, glossary, index) (Nonfiction. 8-11)