ma(;ni:ti(' kxi'kiumknts. 



<Jii iiaoiiiit of llie iiiiiK-rfeotioii nf tlie inn^iiietoiiK-tric a|>|«iiialUM at mir 

 «lis|iitsiil. we were ol»li)j;t'il to content ourselves witli ii n-hitive iluteriiiiiintioii of 

 the lioi;iz(intrti intensities of terrestiul nm'j;iii'tisni lit Tokio ami at Sa|)|i«iro. 



TlW nieflioil consisteil in vihrntin-^ in a liorizontil plane at the two liM-aiitiu« 

 a niagiief wliich wivs jiernianent enongli to umleri^o no a]>|>nrialilf eliange in the 

 jtrm-ess of trans|>ortatioii. Tiie niethoil of ohseriinn »lie time of viliration was 

 the same us that nsed liy one of ns on tlie Knnnnit of FMJiiioyama; it is tlesTriUil 

 on pa<;e T)") of Memoir No. 7 of tho Science Ilepiirtnient of this university 

 (Kepoit •III the Meteomlojiy of Tokio tor 18S0, by I'rof. Mentlenhall I, hut if will 

 not lie out of |)lace here to rwapitnlalt; the most important f<'jitnn»8. 



The inaiinet was susiiemled liy means of a silk tilux", whos<' tor-^iiln was 

 found to lie negligeahie, and was swuni; in a ^lass ciuse, which proti.rted it from 

 currents of air. On the glass cjise there was |iasted n gnuluatt'd scale hy which 

 the arc of vibration was read oH". The tt^'ini'eratnre at tiie lime of swiTiging 

 was shown by a thermometer inserted in this glass case. As, however, small 

 variations of the magnetic moment due to variations of temperatim- could not 

 be conveniently ascertained, and as, ni(»reover, the extreme variations maircely 

 exceeded 2 or 3 degrees, it was considered unnecessary to introilucuany allowancü 

 for this in the time of vibration. Tlie exact ailjustmeiit of the li'iri/.ciiitatify 

 of the magnet being a matter of some diflicnlty, several obst^rvations were maile 

 with a re-adjustment of the level Iwfore ejich, other things remaining the same. 



The time of transit of a mark in the middle of the end of the magnet 

 across a vertical line traced on the glass case wa.s ol>servi>il by a tele.*coiie plac<Kl 

 some metres distant and was reconled on the chnjuograph. In the miMsurenient 

 of the time from the chronogmph sheet iisimlly from -SO to IfKl i-om|»lete 

 vibrations were taken, so that the error ilue to this is Indieve«! to fall far short of 

 those arising from other sources. 



Three magnets were carried, two of which were kindly lent us by the 

 authorities of Kobu Daigakko. A comparison of the magnetic moments before 

 and after the Sai>|ioro e.xcursion shows that two of the tlmn? njagnets had settli-d 

 into a very stable magnetic state. Each of the magnets was provided with a 

 holder to which the suspending fibre cotdil lie fastened. 



The oliservations are arrangeil in the following tables: - 



OlV<EnVATTONs \T TuKIO UKKORK <iOrx<i TO !^,\rii>ito. 



liiiH- Mi.-uii Tim«' .Mnaii 



Mn^'. Ii:itc uiiiri>in-ct»'(l) Arc Uorn-'toiU Tein|>, 



1 Tnly .-51 13.3123 4=.S 13.310«) 2«=.9 



.\ul'. 1 13:',2:.3 C, .7 I3.'J224 :J0" 



