Hobby horses

Natural History, June, 2004 by David Gordon Wilson, Joan Lehmkuhl, Adam Summers

In his "Biomechanics" column "Meddling with Pedaling" (3/04), Adam Summers writes, "The first Bicycle ... debuted in 1817 as a toy, rather than as transport." But the bicycle historian Hans-Erhard Lessing would surely object to this. He points out that in 1815 the Indonesian volcano Mount Tambora launched so much dust into the atmosphere that 1816 was "the year without a summer": crops failed, there was little food for horses or men, and horses were slaughtered. Baron von Drais therefore invented the Hobby Horse bicycle at a time when it was needed for transport.

A second, unrelated point: there must have been an error in the quoting of 350 watts exerted by walkers and pedalers at the speeds indicated. The actual value should be around 150 watts.

David Gordon Wilson

MIT

Cambridge Massachusetts

It strikes me that the Hobby Horse version of the bicycle could be adapted to help people with ambulatory difficulties. I can see one made with four wheels for stability and the seat between them, with a hand bar along each side or with the usual kind of handlebar. People whose legs cannot bear the full body weight, or can do so only for short times, but can move in a walking motion, could be held in a manner that would put them more at eye level with walking people.

Joan Lehmkuhl, R.N.

Nampa, Idaho

ADAM SUMMERS REPLIES: I am not surprised that, as David Gordon Wilson reports, bicycle historians might have more to say about the vehicle's origins. As for the figure of 350 watts, it refers to the metabolic input, not the output of mechanical power. In other words, a very efficient human "engine" needs 350 watts' worth of food fuel to obtain a mechanical power of about 150 watts.

I agree with Joan Lehmkuhl that new means of assisting the physically challenged with wheels could be explored. As Steven Vogel points out in his book Cat's Paws and Catapults: Mechanical Worlds of Nature and People, nature makes little use of wheels because the terrains normally encountered by animals are not suited to smooth rolling.