ABSTRACT
The value of electrical power is enormously increased by the fact that it can be stored. This is accomplished in cells which are distinguished from those used in the generation of electricity on a small scale for electric bells, telephones, and experimental work, by being called storage cells, or secondary cells, or, more properly, accumulators. The total quantity of electricity depends upon the voltage and the current strength, and an instrument for measuring the product of these is called a wattmeter. In generating stations the instruments record on rolls of paper the changes in the electro-motive force, strength of current, and quantity of electricity produced, so that very accurate calculations of the cost can be made. The size of the wire required to transmit electricity over a distance is determined by the heating effect. The transmission of electricity at high voltage necessitates special precautions, for not only is the tendency to leakage immeasurably greater, but a shock is highly dangerous.
