Ox THE MECHANICAL EQUIVALENT OF HEAT 



419 



Each determination of resistance with each of these experiments 

 gives one value of the mechanical equivalent. As Lorenz's result was 

 only in illustration of a method, I have not included it among the exact 

 determinations. 



TABLE XXXI. 



The result found by Joule was J= 25187 in absolute measure using 

 feet and degrees F., which becomes 429-9 in degrees C. on a mercurial 

 thermometer and in the latitude of Baltimore, compared with water 

 at 18-6C. 



TABLE XXXII. EXPERIMENTS OF JOULE. 



The experiments of H. F. Weber 36 gave 428-15 in the latitude of 

 Zurich and for 1 C. on the air thermometer and at a temperature of 

 18 C. This reduced to the latitude of Baltimore gives 428-45. 



My own value at this temperature is 426-8, which agrees almost 

 exactly with the fourth value from my own determination of the abso~ 

 lute unit. 37 



K Given -9912 by mistake in the other tables. 

 3Phil. Mag., 1878, 5th ser., v. 135. 



37 The value of the ohm found by reversing the calculation would be -992, almost 

 exactly my value. 



