wheelbarrow boards could be dendrochronologically dated to 1537 for one wheelbarrow and the 1530s for the other. Modern wheelbarrows Modern day wheelbarrows are generally made from plastic or metal and generally come with either a pneumatic tyre, semi-pneumatic tyres, or solid tyre. Modern wheelbarrows come in four standard shapes, the home gardener shallow-tray variety, the builder’s barrow, the square tray utility barrow and the brick barrow. Plastic wheelbarrows can be beneficial as they are light in weight reducing physical demand on the user. But plastic wheelbarrows are also suited to lighter loads. Steel wheel barrows can handle heavier loads with carrying capacities of up to wet, or dry. Steel wheelbarrows more effectively transport heavy, jagged material without damaging the wheelbarrow and are often better suited to construction applications. Modern variations In the 1970s, British inventor James Dyson introduced the Ballbarrow, an injection molded plastic wheelbarrow with a spherical ball on the front end instead of a wheel. Compared to a conventional design, the larger surface area of the ball made the wheelbarrow easier to use in soft soil, and more laterally stable with heavy loads on uneven ground. The Honda HPE60, an electric power-assisted wheelbarrow, was produced in 1998. Power assisted wheelbarrows are now widely available from a number of different manufacturers. Powered wheelbarrows are used in a range of applications; the technology has improved to enable them to take much heavier loads, beyond weights that a human could transport alone without assistance. Motorized wheelbarrows are generally either diesel powered or electric battery powered. Often used in small-scale construction applications where access for larger plant machinery might be restricted. See also Cart Dolly Flatbed trolley Hand truck Wheelbarrow race Wheelbarrow Olympics References M. J. T. Lewis, "The Origins of the Wheelbarrow," Technology and Culture, Vol. 35, No. 3. (Jul., 1994), pp. 453–475 Andrea L. Matthies, "The Medieval Wheelbarrow," Technology and Culture, Vol. 32, No. 2, Part 1. (Apr., 1991), pp. 356–364 External links The Wheelbarrow, The Medieval Technology Pages. How to Downsize a Transport Network: The Chinese Wheelbarrow, Low-Tech Magazine. Animal-powered vehicles Chinese inventions Gardening tools Hand barrows