CHAPTER XX. CURRENT STRENGTH 142

Strength of Current.--Unit of Current Strength; The Ampere.--Measurement of Current Strength.--The Tangent Galvanometer.--The Ammeter.--The Voltameter.--Unit of Quantity; The Coulomb.--Electrical Horse-power; The Watt.--Ohm's Law.--Internal Resistance and Current Strength.--Exp. 142, Having a cell with large plates, to find how the strength of the current is affected by changes in the position of the plates, the external resistance being small.--Exp. 143, Same as Exp. 142, but with small plates.--Exp. 144, To find whether the changes in current strength, due to changes in internal resistance, are as great when the external resistance is large, as they are when the external resistance is small.--Discussion, with examples.--Arrangement of Cells and Current Strength.--Cells in Series.--Cells Abreast.--Exp. 145, To find the best way to join two similar cells when the external resistance is small.--Exp. 146, To find the best way to join two similar cells when the external resistance is large.--Best Arrangement of Cells.