Resistance of Metals and Alloys, 



283 



100° C. a straight line was drawn and prolonged both ways. 

 The point where this line cuts the axis of temperature was at 

 a distance of — 283*4 divisions from the zero Centigrade 

 point. This gave the platinum temperature absolute zero. 

 From the measured value of the platinum resistance in any 

 bath we could then deduce the platinum temperature accord- 

 ing to this wire. The numbers in the fourth column are so 

 deduced. Hence when plotted in terms of platinum tempera- 

 ture the curve of platinum resistance is a straight line. The 

 mean temperature-coefficient of this wire between 0° 0. and 

 100° is -003529. 



A similar series of observations was made with the other 

 platinum wire. 



Thin Platinum Wire. 

 Length =100 centim. Mean diameter =0*0078297 centim. 

 Mean cross-sectional area ='000048148 sq. centim. 



Log M [^^] =2-6825775=10^. 



Kt. 



t°. 



Pt> 



pt. 



Remarks on nature of 

 Bath. 



38-806 



196-6 



18684 



193-5 I 

 138-00 j 



Taken in melted paraffin 



34-142 



139-2 



16439 



wax. 



30-850 



98-35 



14854 



98-40" 





30-252 



90-5 



14566 



90-70 





29-440 



27-677 



80-3 

 59-95 



14175 

 13326 



8065 

 60 50 ' 



Taken in paraffin oil. 



26-905 



50-75 



12954 



51-35 





25-997 



39-60 



12517 



40-15 J 





24*213 



18-45 



11658 



18-85 





24-141 



17-95 



11623 



1770 





24-038 



16-30 



11574 



16-65 





24-047 



16-20 



11578 



16-55 





23-928 



14-95 



11521 



15-25 





23-726 



12-70 



11424 



12-95 





23-669 



11-85 



11396 



12-10 





22-783 



1-25 



10970 



1-30 



Taken in melting ice. 



22-717 



0-55 



10938 



0-55 





19-227 





9257 



- 41-2 [ 



Taken in solid carbonic 

 acid and paraffin. 



15-830 



... 



7622 



!- 81-9 | 



Taken in solid carbonic 

 acid and ether. 



14-438 



13-848 





6952 

 6668 



- 99-3 "I 

 -106-1 j 



Taken in liquid ethylene. 



6-326 





3046 



-197-1 



Taken in liquid oxygen. 



Volume-specific resistance at 100° C. = 14923 C.G.S. units, 

 Ditto ditto at 0°C.= 10917 „ „ 



Mean temperature-coefficient between 



0°andl00°C ='003669 = *. 



Reciprocal of temperature-coefficient = — 272*5=— -. 



U2 



