160 Prof. Weber 07i the Application of Magnetic Induction 



time of oscillation) attained its maximum deflection to the east 

 (or west). This was noted by the observer, after having marked 

 down the needle's position when at rest. The needle now 

 returned, and after nine seconds passed throiigh the magnetic 

 meridian. At this moment followed the second (negative) induc- 

 tion stroke, caused by turning the inductor back through 180°, 

 whereby the needle was accelerated in its returning motion. 

 After nine seconds, the needle, thus accelerated, attained its 

 maximum western (or eastern) deflection, which was again noted, 

 and so forth. No. in the following table shows the original 

 position of rest, Nos. 1 to 16 show the sixteen succeeding elon- 

 gations observed as above described. These observations lasted 

 scarcely five minutes. 



Table I. 



Gottingen, 1852. Aug. 3, O^^ SO™— 0^ 25°». 



After the last observation, the clamp for increasing the damp- 

 ing power of the galvanometer was immediately closed; and 

 during the damping action the position of the inductor was 

 changed, so that, — 1, its own axis stood vertical ; 2, the axis 

 around which it was revolved 180° backwards and forwards was 

 exactly horizontal and parallel to the magnetic meridian. This 

 was effected by means of the level described in fig. 1. After 

 removing the clamp for damping, the second series of observa- 

 tions was made in the same manner as the first. This series, 

 however, was made four times at intervals of ten minutes, or as 

 soon as the needle had again come to rest. After these four 

 series of observations, during which the inductor's position was 

 unchanged, followed the last series, in which the inductor had 

 the same position as at first. The following table gives a 

 summary of the six series of observations, which, including the 

 time requisite for damping and changing the inductor's position, 

 required 1^ SO*" to complete. The several series are denoted by 

 the letters A, B, C, J), E and F. 



