REVIEW. 265 



14. (a.) Explain (by figures) electric induction, (b.) Explain 

 the charging of a Ley den jar. (c,) When charged, what is the 

 electric condition of the outside and inside of the jar ? 



15. (a.) Give the sources of atmospheric electricity, and (6.) the 

 effects of lightning. 



16. (a.) What is the effect of breaking a magnet ? (&.) Give a 

 theory of magnetism that is competent to account for the properties 

 of magnets, broken or unbroken. 



17. (a.) How do soft iron and tempered steel differ as to suscep- 

 tibility to magnetism ? (b.) Describe one method of magnetizing a 

 steel bar. 



18. The influence of the earth's magnetism upon a magnetic 

 needle is merely directive, (a.) Explain what this means, (ft.) 

 Show why it is so. 



19. (a.) What is meant by electromotive force? (b.) Describe 

 Grove's battery and its mode of action, (c.) Why are battery zincs 

 generally amalgamated ? 



20. (a.) Describe Oersted's apparatus, and (&.) tell what its use 

 teaches, (c. ) Describe the construction of the astatic galvanometer. 



21. (a.) Describe an electro-magnet, and (b.) tell what its advan- 

 tages are. (c.) State the principle of the electric telegraph. 



22. (a.) Describe a Ruhmkorff's coil, and (6.) explain its action. 



23. (a.) Define electrolysis and electrolyte. (6.) Describe the elec- 

 trolysis of water, (c.) Give a clear account of some branch of 

 electro-metallurgy, (d.) What is meant by the terms electro-positive 

 and electro-negative ? ; s .? 



24. (a.) Define physics. (&.) Name and define the three conditions 

 of matter, (c.) What do you understand by energy ? (d.) Explain 

 what is meant by foot-pound. 



25. (a.) What condition of the atmosphere is desirable for experi- 

 ments in frictional electricity? (&.) Why? (c.) How could you 

 show, experimentally, that there are two opposite kinds of elec- 

 tricity ? 



26. (.) Describe the experiment with Faraday's bag, and (6.) 

 state what it teaches, (c.) Describe the dielectric machine, and (d.) 

 explain its action. 



27. In an air-pump, the capacity of the cylinder is one-fourth 

 that of the receiver. Under ordinary atmospheric conditions, both 

 together contain 62 grains of air. Find the capacity (a.) of the 

 receiver, (&.) of the cylinder. After 5 strokes of the piston, (c.) how 

 many grains of air would be left in the receiver ? What would be 

 its tension (d.) in pounds per square inch? (e.) In Kg. per sq. cm.? 

 (/.) In inches of mercury ? 



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