viii CONTENTS. 



in Hyde Park. 4. Property of electro-magnets. 5. Alternate 

 transmission and suspension of the current. 6. How this pro- 

 duces a moving power. 7. Voltaic piles used by Mons. Froment. 

 8. Forms x>f his electro-motive machines. 9. Details of their 

 construction. 10. Regulator applied to them. 11. Their appli- 

 cation to divide the limbs of philosophical instruments. 12. 

 Their wonderful self-acting power. 13. Application of electro- 

 motive power to the telegraph by Mons. Froment. 14. Micro- 

 scopic writing. 15. Electric clocks . . . . .193 



