OP ARTS AND SCIENCES. 



231 



separation of the carbons, which is the length of the arc, the unit being 

 ■^Tj of an inch ; the second column gives the equivalent resistance in 

 ohms, which is the electromotive force between the carbons divided 

 by the corresponding value of the current ; the third column states 

 whether the arc was a silent (S.) or whistling (W.) one. The value 

 of the current given over each table is the mean of the values found 

 in the various separate measurements. 



Upright Arc. 

 TABLE III. TABLE IV. 



Current = 3.27 amperes. Current = 5.04 amperes. 



Length 

 of Arc. 



0.25 



0.50 

 0.50 

 1.00 

 1.00 



Resistance. 



5.51-5.93 

 7.41 



6.96* 



9.50 



9.86* 



Character. 



w. 



W. (slightly. 



Length 

 of Arc. 



1 



2 

 3 

 4 

 5 



6 



7 



Resistance. 



5.67 



8.14 



9.51 

 10.02 

 1057 

 11.10 

 11.60 



Character. 



W. (slightly.) 

 S. 



TABLE V, 



Current = 7 amperes. 



Length 

 of Arc. 



0.25 

 0.50 

 1.00 

 1.00 

 2.00 

 200 

 3.00 

 3.00 

 4.00 

 4.00 

 5.00 

 6.00 

 7.00 

 8.00 

 9.00 

 12.00 

 12.00 

 14.00 



Resistance. 



2.49 

 2.89 

 3.60 

 3.55 

 5.28 

 5.17 

 6.28 

 6.41 

 6.77 

 6.72 

 6.97 

 7.25 

 7.51 

 7.80 

 8.06 

 8.97 

 8.90 

 9.31 



Character. 



w. 



" (low.) 



s. 



S. (flaming.) 



TABLE VI. 



Current = 7.94 amperes. 



* These results were given by Carrd carbons. 



