PART I : STATIC ELECTRICITY 



CHAPTER I 



GENERAL ACCOUNT OF COMMON 

 PHENOMENA 



Electrification by friction Actions between bodies both electrified by 

 friction Two kinds of electrification Law of electric mechanical action 

 Electric actions not magnetic Conduction and insulation Gold-leaf 

 electroscope Electrification by induction Detection of kind of charge 

 by the electro.^ <>[" Nature of induced electrification Only the outer 

 .-urface of a conductor is charged The two electrifications always occur 

 together, iiidm -iiiir a:h othT Discharge of electrification Frictional 

 machines Ease of discharge from points Lightning conductors 

 Electruphnnis Bennett's doubler Belli's machine Holt/, s machine 

 Wim>hur>t'.> inachiiif Thj Leydt-n jar Franklin's jar Residual charge. 



Electrification by friction. When a stick of sealing-wax 

 has been rubbed with anv clrv woollen material it is found to 

 attract dust, small pieces of paper, bran, or other very light par- 

 ticle*. A drv glas> rod after being rubbed with silk acts in a 

 .similar way, and the property i> Chared by many other substances. 



When showing this peculiar action the surface of the rubbed 

 rod is said to be electrified, to have undergone electrification, or to 

 po-c electricity, this term being derived from the Greek iiXetcrpov 

 amber, a substance \\liicli was. known to the ancients to possess 

 the>e electrical properties. 



Manv vcrv simple and interesting experiments may be made on 

 electric actions. We may, for instance, attract egg-shells, paper 

 rings, wood laths .suspended by silk threads, ^c., by electrified rods 



aling-wax, ivsin, ebonite, and glass. Perhaps the most striking 

 experiment is the electrification of dry paper. If several sheets 

 of paper are thoroughly dried before the fire or by ironing with a 

 hot iron, and are, while still quite hot, laid in a pile and stroked 

 sharply with the finger-nails, they adhere very closely together. 

 It .separated, they for a short time show electrification to a very 

 high degree, and attract small pieces of paper with great violence, 

 adhere to the wall if brought near to it, and so on. 



In making these elementary experiments, we find that for 

 different substances certain "rubbers" are the most efficient. 



1 A 



