eric
/
MaineEdu


			
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869
							<HTML lang="zh">
	<HEAD>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
<meta name="MSSmartTagsPreventParsing" content="TRUE">
		<META Name= "description" Content = "Ancient Tian Wen Tai">
		<META NAME="distribution" content="Global">
		<META NAME="rating" content="Safe For Kids">
		<META NAME="copyright" content="Marilyn Shea">
		<meta name="Author" content="Marilyn Shea">
		<META NAME="classification" content="Education">
		<META Name = "keywords" Content = "China, Chinese, astronomy, Tian Wen Tai, ancient observatory, Marilyn Shea">
		<TITLE>Synchronome - 中国天文学 - 两台摆的电子钟 Chinese Astronomy</TITLE>
		

	</HEAD>

<BODY bgcolor=#333333 text=#FEFAFA link=#FFFFFF vlink=#FFFFFF alink=#FF0000>
		<CENTER>
<TABLE border="0" cellpadding="0" cellspacing="2" width="200">
<TR>
	<TD width="80" align="center"><A href="0040GaoLu_9292w.html"><IMG src="../tianimage/previous.gif" height="30" width="30" border="0" title="Previous"></A></TD>
	<TD width="80" align="center"><A href="../index.html#39"><IMG src="../tianimage/home.gif" height="30" width="30" border="0" title="Home"></A></TD>
	<TD width="80" align="center"><a href="0041Chen_Zungui9293w.html"><IMG src="../tianimage/next.gif" height="30" width="30" border="0" title="Next"></a></TD>
</TR>
</TABLE>
</CENTER>
		<center>
			<table border="8" cellspacing="2" cellpadding="4" bgcolor="black">
				<tr>
					<td bgcolor="black"><a href="0041Chen_Zungui9293w.html"><img src="../tianimage/0038_synchronome6745w.jpg" title="Synchronome Two Pendulum Clock" height="600" width="675" border="0"></a></td>

				</tr>
			</table>
		</center>
		<div align="center">
			<div align="center">
				<div align="center">
					<h1><font size="-1" color="white" face="Verdana, Arial, Helvetica, sans-serif">Synchronome - Two Pendulum Electric Clock <br>
						</font><font size="+1" color="white" face="Verdana, Arial, Helvetica, sans-serif">两台摆的电子钟</font><font size="-1" color="white" face="Verdana, Arial, Helvetica, sans-serif"><br>
						</font></h1>
				</div>
			</div>
			<p><br>
			</p>
		<div align="left">
			<table width="60%" border="0" cellspacing="2" cellpadding="0" align="center">
				<tr>
					<td><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">Synchronome clocks were first made in 1900.  They were known for their accuracy.  The basic design called for a swinging pendulum to receive a boost of electricity, thus preventing the decay of the swing.  Not only were they accurate but they were designed as master clocks.  The central clock could control the time shown on clock faces in many remote locations.  They were commonly used in schools and factories.  </FONT>
						<p><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">In 1921, William Hamilton Shortt, the director of the company, invented a new form of pendulum clock that used two pendulums in synchrony to measure time (Patent Number 187814).  The master clock's pendulum was encased in a vacuum tube to reduce drag.  It delivered an electric pulse to the pendulum of a second clock that corrected the swing much more accurately.  The clocks were accurate to a millisecond per day.  If you are interested in the mechanics of clocks, <a href="http://www.electric-clocks.nl/clocks/fr/" target="_blank">J E Bosschieter</a> has great animations showing the workings of the clock. Choose your language by clicking a flag and then go to Page 10.  You will need the Shockwave plug-in to view them.</font></p>
						<p><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">Only about 100 of the clocks were made and they were used primarily in observatories around the world.  The clocks improved the accuracy of measurement in astronomy and were used into the 1950s when they were replaced with atomic clocks.</font></p>
						<p><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">This Synchronome housed at the Beijing Ancient Observatory (</font>古观象台<font size="-1" face="Verdana, Arial, Helvetica, sans-serif">) includes a second hand and a 24 hour dial.  </font></p>
					</td>
				</tr>
			</table>
		</div>
		<div align="center">
			<p align="left"><br>
			</p>
			<HR>
			<P align="left"><font size="-1" face="Verdana, Arial, Helvetica, sans-serif">http://hua.umf.maine.edu/China/beijing2.html<BR>
						Last update: September 2007<BR>
						© Marilyn Shea, 2007 </FONT></P>
			<HR>
			<br>
		</div>
	</BODY>


</HTML>