DISCOURSE OF W. B. TAYLOR. 253 



Having thus succeeded in exalting the initial induction, Henry 

 proceeded in his investigation. Distinct currents of the third, 

 fourth, and fifth orders were readily obtained from it; and as was 

 anticipated, with their signs (or directions) the reverse of the cor- 

 responding orders derived from the terminal induction. In other 

 respects "the series of induced currents produced at the beginning 

 of the primary current appeared to possess all the properties belong- 

 ing to those of the induction at the ending of the same current." 



In the course of these investigations the idea having occurred to 

 him " that the intense shocks given by the electric fish may possibly 

 be from a secondary current," as it appeared to him that "this is 

 the only way in which we can conceive of such intense electricity 

 being produced in organs imperfectly insulated and immersed in a 

 conducting medium," he endeavored to simulate the effect by ar- 

 ranging a secondary wire coil furnished with terminal handles, over 

 a primary copper ribbon coil, the two being insulated as usual. 

 "By immersing the apparatus in a shallow vessel of water, the 

 handles being placed at the two extremities of the diameter of the 

 helix, and the hands plunged into the water parallel to a line join- 

 ing the two poles, a shock is felt through the arms." 



The former experiment of obtaining an induction shock from 

 one room to another through a partition, was repeated on a still 

 larger scale. All the coils of copper ribbon having been united in 

 a single, continuous conductor of about 400 feet in length, "this 

 was rolled into a ring of five and a half feet in diameter, and sus- 

 pended vertically against the inside of the large folding doors which 

 separate the laboratory from the lecture-room. Beyond the doors, 

 in the lecture-room and directly opposite the coil, was placed a helix 

 formed of upwards of a mile of copper wire, one-sixteenth of an 

 inch in thickness, and wound into a hoop of four feet in diameter. 

 With this arrangement, and a battery of 147 square feet of zinc 

 surface divided into eight elements, shocks were perceptible in the 

 tongue when the two conductors were separated to the distance of 

 nearly seven feet. At the distance of between three and four feet, the 

 shocks were quite severe. The exhibition was rendered more inter- 

 esting by causing the induction to take place through a number of 

 persons standing in a row between the two conductors." 



