CINXE.COM

<!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=559"> 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%3Bseq%3D559%3Bnum%3D507" 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="seq559">Section 43 - Page 507</h2><div id="mdpPage"><p class="Text">[ 507 ] LVII. On a Modified Resistance-Balance. By Professor SILVANUS P. THOMPSON, B.A., D.Sc.* SEVERA [Plate XVI.] EVERAL forms of Resistance-Balance modified for the purpose of facilitating the accurate measurement of small resistances or small differences of resistance are known. The modification due to Prof. Fleeming Jenkin†, and the Double- bridge of Sir W. Thomson are perhaps the earliest and least-known of these. Kirchhoff's arrangement, as further modified by Matthiessen, is well known under the name of the "divided-metre " bridge. The method of using this form of balance suggested by Professor G. Carey Foster §, in which the difference between two nearly equal resistances is expressed directly in terms of a length of a graduated wire whose resistance is very accurately known, is so extremely reliable, that probably no one who once adopts this method of testing resistances will ever go back to the cruder and less accurate methods. The essence of the method lies in arranging the coil whose resistance is to be measured and the standard coil to which it approximates in series with the graduated wire, in such a manner that the positions of the two coils can be interchanged. The points of the wire at which the poten- tial is the mean between the potentials at the two ends of the series having been determined, both before and after the interchange, the resistance of the length between these two points is the desired difference. A special modification of the balance for facilitating Foster's method was described to the Physical Society in Dec. 1879 by Dr. J. A. Fleming ||; and has been since then systematically used in the Cavendish Laboratory by the Committee on Electrical Standards for the comparison of standard coils. Although extremely con- venient, Dr. Fleming's Balance appears to me to be open to several objections. In the first place, the interchange of the two coils, though much more easily accomplished than in the older divided-metre form, is effected by lifting the termi- nals of each coil out of one of two pairs of mercury-cups, and removing them to the other pair. This operation is not * Communicated by the Physical Society. Read February 23, 1884. † Report of Committee on Electrical Standards. Proc. Roy. Soc. vol. xi. p. 313 (1861). Proc. Soc. Telegr. Engin. vol. i. pt. 2, p. 196 (1872). Proc. Phys. Soc. vol. iii. p. 174; Phil. Mag. ser. 4, vol. ix. (1880); Telegr. Journal, vol. viii. p. 3 (1880). p. 109 </p><p><a class="navigation" href="/cgi/ssd?id=uc1.b3728192;page=ssd;view=plaintext;seq=558;num=506"> Previous Page </a><br /><a class="navigation" href="/cgi/ssd?id=uc1.b3728192;page=ssd;view=plaintext;seq=560;num=508"> 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) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); </script> <script type="text/javascript"> try { var pageTracker = _gat._getTracker("UA-954893-23"); // turn semicolons into ampersands for analytics reporting pageTracker._setDomainName(".hathitrust.org"); var href = (location.pathname + location.search).replace(/;/g, '&'); pageTracker._trackPageview(href); } catch(err) { } try { // track hierarchy if ( location.pathname.indexOf("XXX/cgi/pt") > -1 ) { var nextTracker = _gat._getTracker('UA-39581946-1'); nextTracker._setAllowHash(false); nextTracker._setDomainName(".hathitrust.org"); href = [location.pathname]; var url = $.url(); href.push("id=" + encodeURIComponent(url.param('id'))); if ( location.pathname == '/cgi/pt' ) { href.push("view=" + url.param('view')); if ( url.param('seq') ) { href.push("seq=" + url.param('seq')); } } else { href.push("start=" + (url.param('start') ? url.param('start') : "1")); } href = href.join("/"); nextTracker._trackPageview(href); } } catch(err) { console.log(err); } </script> </body> </html>