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<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:cc="http://creativecommons.org/ns#" xmlns:foaf="http://xmlns.com/foaf/0.1/" xmlns:h="http://www.hathitrust.org" lang="en" xml:lang="en" version="XHTML+RDFa 1.0"> <head profile="http://www.w3.org/1999/xhtml/vocab"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link about="[_:uc1.b3728192]" rel="foaf:isPrimaryTopicOf" href="https://hdl.handle.net/2027/uc1.b3728192" /> <title>The philosophical magazine, ser.5 v.17. - Text-only - Full View | HathiTrust Digital Library</title> <meta name="viewport" content="width=device-width, initial-scale=1" /> <link rel="stylesheet" href="/common/alicorn/css/main.201910.css" type="text/css" /> <link rel="stylesheet" href="/ssd/ssdstyles.css" type="text/css" /> <script src="/common/alicorn/js/utils.201910.js"></script> <script src="/ssd/access_banner.js"></script> <script src="/ssd/toc_links.js"></script> </head> <body><div id="mdpUberContainer"><div id="mdpHeaderContainer"><div id="mdpPageHeader"><a name="top" id="top"></a><h1>The philosophical magazine, ser.5 v.17. | HathiTrust Digital Library</h1><p><a style="font-weight: bold" href="https://hdl.handle.net/2027/uc1.b3728192?urlappend=%3Bseq=560"> View this item in the Book Viewer </a></p><p>Use of this online version is subject to all U.S. copyright laws. Please do not save or redistribute this file.</p><div id="SSDcontact">For questions or comments, contact HathiTrust.org at <a href="mailto:support@hathitrust.org">support@hathitrust.org<br /></a></div><div><p>You have one page at a time access to this item. Authenticated members of HathiTrust institutions who have a print disability may have full-text access to this item. <a href="http://babel.hathitrust.org/cgi/wayf?target=https%3A%2F%2Fbabel.hathitrust.org%2Fcgi%2Fssd%3Fid%3Duc1.b3728192%3Bpage%3Dssd%3Bview%3Dplaintext%3Bseq%3D560%3Bnum%3D508" id="loginLink"> Login</a> to determine if you have access and see all volumes that are available when searching. For more information, see <a href="http://www.hathitrust.org/accessibility">HathiTrust Accessibility</a>. Page at a time access to this item is also available via our fully-styled HathiTrust interface.</p></div><div id="SSDjumps"><a href="#biblio">Go to full bibliographic information</a><br /><a href="#toc">Go to table of contents</a><br /><a href="#SkipToBookText">Skip table of contents and go to current page</a></div><div id="mdpItemMetadata"><h2><a name="biblio" id="biblio"></a>Full Bibliographic Information</h2><div class="mdpMetaDataRow"><div class="mdpMetaDataRegionHead">Title</div><div class="mdpMetaText"><span about="[_:uc1.b3728192]" property="dc:title" rel="dc:type" href="http://purl.org/dc/dcmitype/Text" content="The philosophical magazine, ser.5 v.17.">The philosophical magazine, ser.5 v.17.</span></div></div><div xmlns:METS="http://www.loc.gov/METS/" xmlns:PREMIS="http://www.loc.gov/standards/premis" id="mdpFlexible_1"><div class="mdpMetaDataRow"><div class="mdpMetaDataRegionHead">Published </div><div class="mdpMetaText"><span property="cc:attributionName" rel="cc:attributionURL" href="https://hdl.handle.net/2027/uc1.b3728192" content="London, England :Taylor &amp; Francis,1798-c1977."></span><span property="dc:publisher" content="London, England :Taylor &amp; Francis,1798-c1977.">London, England :Taylor &amp; Francis,1798-c1977.</span></div></div><div class="mdpMetaDataRow"><div class="mdpMetaDataRegionHead">Description </div><div class="mdpMetaText">v. :ill. ;25 cm.</div></div><div class="mdpMetaDataRow"><div class="mdpMetaDataRegionHead">Rights </div><div class="mdpMetaText"><a target="_blank" href="http://www.hathitrust.org/access_use#pd-google">Public Domain, Google-digitized. </a></div></div><div class="mdpMetaDataRow"><div class="mdpMetaDataRegionHead">Permanent URL </div><div class="mdpMetaText"><a href="https://hdl.handle.net/2027/uc1.b3728192">https://hdl.handle.net/2027/uc1.b3728192</a></div></div></div></div></div></div><div id="ControlContentContainer"><div class="mdpControlContainer"><div id="mdpContentsList"><p></p><h2><a name="toc" id="toc">Table of Contents</a></h2><ul><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=1;num=">Front Cover</a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=7;num=i">Title Page<span> on page number i</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=9;num=iii">Table of Contents<span> on page number iii</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=15;num=1">Section 1<span> on page number 1</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=38;num=24">Section 2<span> on page number 24</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=46;num=30">Section 3<span> on page number 30</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=64;num=46">Section 4<span> on page number 46</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=77;num=59">Section 5<span> on page number 59</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=87;num=69">Section 6<span> on page number 69</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=93;num=75">Section 7<span> on page number 75</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=100;num=82">Section 8<span> on page number 82</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=129;num=111">Section 9<span> on page number 111</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=137;num=119">Section 10<span> on page number 119</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=155;num=135">Section 11<span> on page number 135</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=164;num=142">Section 12<span> on page number 142</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=170;num=148">Section 13<span> on page number 148</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=177;num=155">Section 14<span> on page number 155</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=178;num=156">Section 15<span> on page number 156</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=187;num=163">Section 16<span> on page number 163</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=197;num=173">Section 17<span> on page number 173</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=213;num=188">Section 18<span> on page number 188</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=220;num=194">Section 19<span> on page number 194</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=244;num=214">Section 20<span> on page number 214</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=271;num=239">Section 21<span> on page number 239</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=277;num=245">Section 22<span> on page number 245</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=283;num=249">Section 23<span> on page number 249</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=299;num=265">Section 24<span> on page number 265</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=309;num=275">Section 25<span> on page number 275</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=316;num=282">Section 26<span> on page number 282</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=338;num=302">Section 27<span> on page number 302</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=352;num=314">Section 28<span> on page number 314</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=359;num=321">Section 29<span> on page number 321</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=366;num=328">Section 30<span> on page number 328</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=392;num=352">Section 31<span> on page number 352</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=407;num=367">Section 32<span> on page number 367</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=417;num=377">Section 33<span> on page number 377</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=432;num=392">Section 34<span> on page number 392</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=438;num=398">Section 35<span> on page number 398</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=445;num=403">Section 36<span> on page number 403</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=451;num=409">Section 37<span> on page number 409</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=480;num=438">Section 38<span> on page number 438</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=489;num=447">Section 39<span> on page number 447</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=501;num=459">Section 40<span> on page number 459</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=533;num=487">Section 41<span> on page number 487</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=540;num=492">Section 42<span> on page number 492</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=559;num=507">Section 43<span> on page number 507</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=617;num=565">Index<span> on page number 565</span></a></li><li class="mdpFeatureListItem"><a href="/cgi/ssd?id=uc1.b3728192;seq=624;num=">Section 44</a></li></ul></div></div><div id="mdpContentContainer"><a name="SkipToBookText" id="SkipToBookText"></a><h2 id="seq560">Page 508</h2><div id="mdpPage"><p class="Text">508 Prof. S. P. Thompson on a convenient in certain cases, as, for example, when the resist- ance is being taken of a wire heated in an oil-bath to various successive temperatures, or when some contact-resistance is to be measured which must on no account be shaken. Again, in Fleming's Balance the graduated wire is bent into a circle and laid in a groove, contact being made by a trigger attached to an arm, pivoted at the centre of the circular wire. This arrangement, though I have heard no complaint of its practical efficiency, is open to two objections. It must be much more difficult to lay the wire with an even stress at all points than is the case with a straight wire stretched between two points. The range of resistances measurable by this bridge is limited to something less than the actual resistance of the graduated wire. Lastly, a circular scale having about 300 divided into 1000 parts is not so easily obtained as a straight metre-scale. I have therefore designed a form of resistance-balance which meets the desiderata. It consists of two parts-a divided wire or rheocord, and an arrangement of mercury- cups, connecting-pieces, and terminals to be attached at the back of the rheocord part. The figure 1, Plate XVI., shows the general arrangement of these two parts; the connexions between the two parts being made by strips of copper 3 millim. thick, secured under clamping-screws. X is the coil whose resistance is to be measured, and S the standard coil. The terminals of each of these coils dip into two large mercury- cups turned in solid copper; these are shown half size in fig. 2, and are marked mn and m'n' respectively. Between these cups lie four parallel bars of solid copper a a', bb', cc', and dd', the ends of which terminate also in mercury-cups. The bars a a and bb' communicate by stout copper con- nexions with the two ends of the rheocord part. The other two bars communicate with the battery terminals and with the terminals for the two balanced coils A and B. In all accurate tests these coils should be approximately equal to the X or S, and should be very nearly equal to one another. As they are not required to be interchanged, they are simply clamped with copper connexions under flat-headed terminal screws. Short stout pieces of copper, amalgamated at the ends, serve to connect the mercury-cups as shown in fig. 1, m being connected with a, n with d, m' with b′, and n' with c. The connexions being thus made, an observation is taken, and the distance x along the scale of the point of contact with the galvanometer-circuit is recorded. Then the connexions are altered, m being placed in communication with b, n with c, m' with a', and n' with d'. This has the </p><p><a class="navigation" href="/cgi/ssd?id=uc1.b3728192;page=ssd;view=plaintext;seq=559;num=507"> Previous Page </a><br /><a class="navigation" href="/cgi/ssd?id=uc1.b3728192;page=ssd;view=plaintext;seq=561;num=509"> Next Page </a><br /> Return to <a href="#top">top</a>. </p></div></div></div></div><script type="text/javascript">var gaJsHost = (("https:" == document.location.protocol) ? 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