166 New Magnetic Electrical Machine. 



apart. A few turns of the wheel furnish mixed gases enough 

 to make a smart explosion. A solution of sulphate of soda in cab- 

 bage water, contained in separated glass cells, submitted to the 

 action of the machine, gives immediately the characteristic chan- 

 ges of color by decomposition ; reversing the motion of the wheel, 

 the reverse change takes place. The light from charcoal points 

 is insupportable. Plumbago gives an intense light. The metal- 

 lic leaves burn with splendor. When a wire is suddenly with- 

 drawn from one of the poles or brass straps, a bright spark is ob- 

 tained, half an inch in length. When the circuit is broken from 

 a smooth and clean metallic surface, an entirely new and beauti- 

 ful appearance presents itself A diffuse, irregular, nebulous 

 spark, darts along the surface, (as 

 seen in fig. 2,) sometimes in sev- ^"' ' 



eral directions at once, to the dis- 

 tance of half or three quarters of 

 an inch. It succeeds with all 

 the metals yet tried, but best 

 with a piece of iron finely stri- 

 ated with a smooth file. When 

 the lever trip is worked, the sec- 

 ondary current frequently plays 

 with an intense green light, 

 across the separations between the pole changers. The shock 

 from the direct current is uncomfortable with dry hands; but 

 when the secondary current is used, it is painful to touch the 

 poles, even with the fingers. It causes the gold leaves of the elec- 

 troscope to diverge strongly, without the aid of a leyden jar, or ex- 

 tended, insulated metallic surfaces. It charges a leyden jar at ev- 

 ery touch. A charcoal point on the knob of the jar, affords a bright 

 light at every touch. I have some time since shown, that the 

 shocks and decompositions produced by the secondary current of 

 flat spirals and helices in connexion with a single pair of plates, 

 were greatly increased, if the surface of the mercury, (or solid 

 conductor,) from which the circuit is broken, be covered with 

 pure water or naphtha. I have since found that oil gives a far 

 greater increase than either. The rationale is now obvious. 

 When the battery circuit is completed, (as shown by Faraday's 

 discoveries of volta-electric induction, ) a feeble secondary current 

 flows in a direction opposite to that of the battery. When the 



