bill (04/27/83)
The article on why nature did not invent wheels or propellers is extraordinarily interesting; but there is one place where nature *did* invent such devices (as was discovered recently) -- namely the flagellar propulsion system of certain bacteria. It has been demonstrated quite conclusively that these flagella are corkscrew-shaped devices that *rotate* in a ball-and-socket bearing. Electron micrographs of the joint show it to be most ingenious. One can draw an analogy between the corkscrew-shaped flagellum and the propellor screw, but I wouldn't want to push it too far as the fluid environment in which the bacteria live is undoubtedly extremely viscous (on these scales). Bill Jefferys Astronomy Dept University of Texas (...ucbvax!nbires!ut-ngp!utastro!bill) (...decvax!eagle!utngp!utastro!bill) ( utastro!bill@utexas-11)