Electricity for public schools and colleges . to make glass jaxs; glass has a highspecific inductive capacity {see Chapter IX.);and the jar can be made thin, or the distancebetween the plates small and therefore thecapacity of the jar large, without a dischargetaking place through the the calculation of K, as well as for the units in which Vis measured, the reader is referred to Chapter X. § 8. The Unit Jar.—If we can fix the capacity of a jar and thedifference of potential between its two coatings, then we havefixed the charge in that jar. A unit jar is a small Leyden jar of some co
Electricity for public schools and colleges . to make glass jaxs; glass has a highspecific inductive capacity {see Chapter IX.);and the jar can be made thin, or the distancebetween the plates small and therefore thecapacity of the jar large, without a dischargetaking place through the the calculation of K, as well as for the units in which Vis measured, the reader is referred to Chapter X. § 8. The Unit Jar.—If we can fix the capacity of a jar and thedifference of potential between its two coatings, then we havefixed the charge in that jar. A unit jar is a small Leyden jar of some convenient shape ; usually so made as to admit ofeasy cleaning and drying, andto insulate well. Connected with the outsideis a knob B, and connectedwith the inside is a knob A,whose distance from B can beregulated by sliding the pieceA C along the graduated rodDE. It is proved experimentallythat the distance between Aand B across which the jar will just discharge itself is directlyproportional to the difference of potential between A and CH. VI. ELEMENTARY DISCUSSION OF CONDENSERS 8/ (It depends also on the curvature of the knobs, and on the mediumbetween A and B ; but we suppose these conditions to remainv:onstant.) Hence, if we keep the distance between A and B fixed, thedifference of potential between A and B at the moment when thejar discharges itself in a spark across the gap A B will also befixed. Let us now put the outer coating of the jar to earth, put Aat a fixed distance (that we will call i) from B, and charge the jarby placing the knob D near the prime conductor of a machine ;and let us suppose that it takes a difference of potential mea-sured by ?i for a spark to pass from A to B. Then on charging the jar we shall shortly perceive a brilliantdischarge to pass from A to B : this discharge leaving the jaruncharged. At the moment of this discharge there was on theinner coating a charge + Q, determined by the relation Q, = K(V,-Vi3)or, by hypothesis, Qi = K rl. Th
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Keywords: ., bookcentury1800, bookdecade1890, bookpubl, booksubjectelectricity
