14 The Rev. T. E. Robinson on the Relation between the Temperature of 



With the exception of 18 and 12, the agreement between the formula and 

 observation is sufficiently close ; and even in them the error is not remarkable, 

 if we consider that a degree of the pyrometer represents 20° of Fahrenheit, and 

 that a little oxidation in the connexions may afiFect the resistance of an entire 

 set. It even seems to me that this prmciple affords a very effectual method of 

 measuring high temperatures in the arts. 



With the wire tj^tj tlie three equations are 



114.55 = a + 6 X 424.25 -ex 130725.0, 

 171. 10 = a + 6 X 1531.93 -ex 753848.0, 

 195.33 = a + bx 2178.70 - e x 1741069.0. 



Hence, 



= 91.4 ; b = 0.05898 ; c = 0.0000141. 



The value of a is certainly too large. I have mentioned the probable effect 

 of the oxidation of the clip ; possibly while looping the broken wire, the con- 

 tact may have been improved, for I found afterwards, that by trying its resis- 

 tance under water while attached to the clip, with a ciurrent = 2.743, the 

 resistance was 76.1. On making the contact perfect it was only 46. 



The values of observed — calculated resistances are 



Part of the errors of the first five are, I think, accounted for ; and the rest 

 is imimportant. 



Lastly, for the wire g\ the equations are 



147.22 = «-h J X 522.27 -ex 96511, 

 240.27 = a + bx 1283.03 - e x 644327, 

 338.67 = a + bx 2148.57 - c x 2694208. 

 HencG 



a = 81.9 ; J = 0.1261 ; c = 0.000007188. 



