Show NEVER NEEDS TO BE WOUND this clock hun until metal parts that constitute its works arc worn out clocks that tell the time with only one band are something of a novelty but they cannot compare with a recently invented clock which never needs winding it will run forever or at least until its metal parts wear out this sounds like the old fallacy of perpetual motion but as a matter of fact Is far from it the new clock runs by using in an ingenious way the energy produced by changes in tern pera ture metal bars which are very sensitive to temperature changes are arranged in such a manner that when the mercury falls and the bars contract this slight motion of the metal is fully used when the thermometer goes up and the bars expand slightly the motion involved in their lengthening Is also made to do work the motion from the bar lifts tiny steel balls from a lower reservoir to an upper one there they are made to turn a wheel in much the same a ay that water turns an old fashioned water wheel the energy resulting from the ex and contraction of metal as the temper autre changes can be used only to operate mechanism like that of clocks and watches which requires only a email amount of power it id too expensive to be used where much power Is required somebody with fondness for math has estimated that to gen crate a single horse power in this way would cost nearly fifty million dol lars |