sun and planet wheels

pl. An ingenious contrivance invented by Watt as a substitute for the crank in converting the reciprocating motion of the beam into a rota tory motion. The central gear ( a ) is called the sungear, and the outer one (6) the planet-gear. In the form hown in the illustration, the revolution of the planet-wheel rotates the sun-wheel, together with its shaft and the fly-wheel. For this purpose the planet-wheel C ( b ) is fast to the pitman (c), and its axis is caused Sun-and-planet Wheels. to revolve around the wheel without the rotation of the planet-wheel on its own axis. [PLANET-WHEEL.] sun-animalcule, s. Zool.: Actinophrys sol. [ACTINOPHRYS.] "It consists of a small bit of globular protoplasm, with spines radiating in every direction from its surface; and when seen in perfect condition for the first time under the microscope with proper illumination it seems to shine like 'the sun in its brightne .' Hence the original observers gave it the name of the Sun -animalcule. Indeed, any old ordinary picture of the sun would do very well for Actinophrys, as conveying a general idea of its form." -John Badcock : Vignettes from Invisible Life , p. 104. IMG:content-0573.jpg:[blocks in formation]