228 Contributions to Electricity and Magnetism. 



Fig. a. 



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Ki 



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third order to twenty-five persons, joining hands ; also shocks per- 

 ceptible in the arms were obtained from a current of the fifth 

 order. 



84. The action at a distance was also much greater than could 

 have been anticipated. In one experiment shocks from the ter- 

 tiary current were distinctly felt through the tongue, when helix 

 No. 1, Fig. 8, was at the distance of eighteen inches above the 

 coil transmitting the secondary current. 



85. The same screening effects were pro- 

 duced by the interposition of plates of metal 

 between the conductors of the different or- 

 ders, as those which have been described in 

 reference to the primary and secondary cur- 

 rents. 



86. Also when the long helix is placed 

 over a secondary current generated in a short 

 coil, and which is therefore, as we have be- 

 fore shown, one of quantity, a tertiary cur- 

 rent of intensity is produced. 



87. Again, when the intensity current of 

 the last experiment is passed through a sec- 

 ond helix, and another coil is placed over 

 this, a quantity current is again produced. 

 Therefore, in the case of these currents, as 

 in that of the primary, a quantity current can 

 he induced from one of intensity, and the con- 

 verse. By the arrangement of the apparatus 

 as shown in Fig. 9, these different results 

 are exhibited at once. The induction from 

 coil No. 3 to helix No. 1 produces an inten- 

 sity current, and from helix No. 2 to coil No. 

 4, a quantity current. 



88. If the ends of coil No. 2, as in the 

 arrangement of Fig. 8, be united to helix 

 No. I instead of coil No. 3, no shocks can be 

 obtained ; the quantity current of coil No. 2, 

 appears not to be of sufficient intensity to 

 pass through the wire of the long helix. 



89. Also, no shocks can be obtained from 

 the handles attached to helix No, 2, in the 



