ST. JOHN, — WAVE LENGTHS OF ELECTRICITY. 



241 



0,07850 cm.). The results are shown in the lower pair of curves in 

 Figure 4 of the Plate, the upper one, as before, being the copper. A 

 comparison of the curves shows the same general result, which appears 

 more distinctly from the following table. 



The successive differences should be in the ratio of 1,3, 5, 7, if the 

 theory of the investigation is correct. The differences for the first two 

 maxima are very small, so that the experimental error in their deter- 

 mination would be relatively large. 



In the case of the fourth maximum, the damping was so great that 

 it was difficult to fix the point with certainty. The difference for the 

 third maximum was relatively large, and the determination of the 

 maximum point was sharp. Taking this difference as a point of ref- 

 erence, the calculated and observed values are shown in the following 

 table. 



The observed half wave lengths for the four wires were as follows: — 



( Copper (diameter 0.1201 cm.), 255.6 cm. 

 (Iron (diameter 0.1126 cm.), 251.6 cm. 



j Copper (diameter 0.07836 cm.), 251.6 cm. 

 i Iron (diameter 0.07850 cm.), 246.8 cm. 



The wires in each pair were as near the same diameter as could be 

 found, the iron of the larger pair having slightly the smaller diameter, 



VOL. XXX. (n. S. XXII.) 16 



