OF WIRES FOR ELECTRICITY. 



323 



to 6, and back from 6, 5, to 1 , and finally without any interposition. Ta- 

 king afterwards the average of observations of the same kind, the influence 

 which the loss of the power of the magnet might have exercised has been 

 thus entirely removed. The length of all the wires collectively was 

 = 16 feet Engl. The experiments are stated in the following table : 



Without any wire interposed ... 

 16 feet of wire No. 1 interposed 



No. 6 



No. 1 1 



No. 18 



No. 24- 



No. 30 



No. 30 



No. 24 



No. 18 



No. 11 



No. 6 



No. 1 



Without any interposition 



Angles of Deviation 



, A 



1 



90-7 

 64-2 

 55-0 

 44-9 

 29-6 

 19-0 

 9-3 

 9-6 

 18-1 

 29-4 

 45-2 

 55-4 

 64-9 

 91-3 



3. 



94-9 

 67-0 

 57-9 

 47-6 

 31-2 

 19-6 

 10-8 

 11-0 

 19-0 

 31-3 

 48-0 

 58-0 

 67-0 

 93-6 



4. 



95-3 

 67-4 

 58-5 

 48-6 

 32-0 

 19-7 

 11-5 

 11-7 

 20-2 

 31-8 

 48-6 

 57-3 

 67-7 

 94-7 



Average 



93-62 

 66-22 

 57-12 

 46-97 

 31-07 

 19-52 

 10-75 

 10-97 

 19-40 

 31-00 

 47-32 

 56-75 

 66-25 

 92-87 



Taking the average of observations made in similar circumstances, 

 the values will be 



Without any wire interposed 

 With the wire No. 1 



No. 6 



No. 1 1 



No. 18 



No. 24 



No. 30 



Angles of Deviation 



observed, calculated. 



93-24 

 66-24 

 56-94 

 47-16 

 31-04 

 19-46 

 10-86 



91-53 

 65-84 

 57-52 

 48-09 

 31-22 

 19-78 

 10-56 



Difference. 



- 1-71 

 -0-40 

 + 0-58 

 + 0-94 

 + 0-18 

 + 0-32 



- 0-30 



The calculation was performed in the following manner : 



Let the strength of the current when it passes through a wire of 

 the' length used in these experiments (that is to say 1 6 feet), and of 

 such a thickness that 2 feet of it weigh 1 gramme, he :=pt/ (where ?/ is 

 an unknown quantity to be determined by the experiment) ; and let the 

 length of the wire of the multiplier, together with the length of the 

 electromotive spiral reduced to the same thickness as the wire be, = x. 



