294 



Profs. Dewar and Fleming on the Electrical 



§18. 



XII. Cadmium. 



A wire of pure cadmium was made and drawn for us by 

 Mr. Greorge Matthey, and with it the following observations 

 were made. 



Length = 99*8 centim. Mean diameter = 0*070366 centim. 



Mean sectional area = 0*0038888 sq. centim. 



L °g 1 { 10 len e cS On ] =4-5906854=log 10 ^. 



R*. 



t°. 



pt. 



pt. 



047136 



182-2 



18367 



179-6 



0-42937 



148-7 



16731 



147-2 



0-35525 



91-10 



13843 



91-25 



0-31144 



51-95 



12136 



52-56 



0-28178 



18-8 



10980 



19-20 



0-27021 



12-75 



10529 



13-05 



0-25827 



1-00 



10064 



1-00 



0-21264 





8286 



- 46-2 



0-17824 





6945 



- 81-9 



0-07575 





2952 



-197-1 



Volume-specific resistance at 0° C. . . 

 Mean temperature-coefficient between 



0°C. and 100° ='00419. 



10023 C.G.S. units. 



§19. 



XIII. Lead. 



This wire was pressed from some very pure lead kindly 

 given to us by Mr. G. Matthey. The lead was prepared by 

 M. Rommelsere in the laboratory of M. Stas in 1884. It 

 was obtained by precipitating lead sulphate from very pure 

 re-crystallized lead nitrate. The lead sulphate was then con- 

 verted into lead carbonate and reduced to metallic lead. The 

 pure lead when it came into our possession was pressed cold 

 in a steel press under a pressure of 25 tons on the square 

 inch into a very uniform wire. 



Length=200 centim. Mean diameter = 0*065631 centim. 



Mean sectional area = 0*003383 sq. centim. 



Logic [ 



10 9 section -i 

 length J 



= 4*2282751=log 10 &. 



