ON A NEW METHOD OF CALIBRATING THERMO-ELECTRIC ELEMENTS 

 FOR USE IN THE MEASUREMENT OF HIGII TEMPERATURES. 



E. L. NICHOLS. 



Exliaustive studies at the luviids of Lk Chatelieu. '), of Barus'-^), aiid 

 of HoLBOKN aiid WiEN ■'■), aiid others hâve led to the conclusion that 

 wheuever theruio-elements consisting of platinmn on the one hand, and 

 of the alloys of that métal with iridium^ rhodium or any other metals 

 of the platinura group on the other, are to be used in the uieasurenient 

 of high températures, it is necessary to niake a thorough calihration of 

 the individual tliermo éléments involved, or at least of the set of éléments 

 manufactured from any given sample of métal. Holman, Lawrence and 

 Barr '), for examj)le, obtained an electromotive force of .03 03 volts 

 from a platinum, platinum-rhodium (10 %) élément at the température 

 of meltiug platinum, vvhereas a simihir clément coustructed of wire from 



^) Lie Cn.VTiiMKH ; Comptes Rendus. Cil, 1886 p. 819; Jonrnal de l'liijsi(iae 

 (2) VI p. 2(J (1887) ; also Mesure des Températures Élevées^ (Paris, 1900) 

 Chapter VI. 



*) Bauus; Bulletin of the U. S. Geoluijical Surveij No. 54; also Anierican 

 Journal of Science XLVIII p. 33G. 



^) Hor.uoRN aud Wien; Wiedkmann's Annulen^ XLVII p. 107 (1892); LVI p. 

 360, (1895). 



") HoLMAN, Lawrence and Baru; Am. Acad. of Arts and Sciences, (1895) 

 p. 218. 



22* 



