THE BICYCLE AND HOW IT WORKS

Like those of The Refrigerator and Central Heating (see pps. 541, J-171, and 677, J-231) the operating principles of the bicycle hardly seem to merit $4.50 worth of analysis, and in going all the way back to the Sumerian invention of the wheel (not to mention Leonardo da Vinci's design for a ball bearing) Urquhart stretches his subject -- and most likely the patience of his readers -- beyond their natural limits. Still, his explanation of the workings of ""derailleur"" gearing and the evolution of caliper brakes are dearer than anything we found in Coombs' more pretentious Bicycling (p. 1146, J-370) and there's a short history of earlier, less sophisticated models as well as acknowledgement of the bicycle's economic role in less motorized societies. Breezy, informative, but like those pneumatic tires -- inflated.