The St. Johns herald., 1894-01-18
ELECTRICITY ON TAP.
The Potent Fluid Now Handled
 Like Any Merchandise.
Something About the Laws Which Con- troI the Movements of the Won de-fuI Power Currents at
 Commercial Rates.

Electricity, once a plaything, then a scientific study, is now commercial product. Twenty years ago electrical energy was generated in the labora- tory for experimental purposes by few physicians as a medicine of some what questionable repute and in weak currents by those who applied it to use in the arts. From the cylinder of glass or mastic, excited by friction to set cork manikins or pitch balls a-dancilg to the dynamo that runs from one to dozen powerful engines is a long step, but one that has been taken within the memory of men who still call them selves young.
 Electricity as a commercial product, according to the New York Sun, is to those that deal in it as commonplace an affair as eggs or butter. The con- ditions and cost of its production are positively known, and the product may be measured almost as the clerk with his yardstick measures dry goods. You may buy your electricity by specific quantities, and if you have the con- veniences may carry it home with you as you would carry any other purchase. It can be sent to you by express or de- livered by messenger, or 1t may be served out over a wire in measured quantity, as gas and water are served through pipes. All this seems nysteri- ous to those not technically educated, because the electricity shops do not count their product by dozens or meas ure it by yards and gallons, but use outlandish denominations and pug zling scientific nomenclature. Never theless the shopkeepers are at home with the mysterious Timber thing in which they deal, and they never stop to think about its mystery, although just beyond the small field which their knowledge covers there lies an un- known area of conjecture.
 Electricity as a commercial product and handy tool, applicable to anyth ing that mechanical power can accom- plish, is thing approximately of only the last ten years. Before that time its cost made it mostly matter ot splendid practical possibilities. Now. with conditions given, a skilled elec' trician can estimate to hair the cost of producing the amount of electricity necessary to yield a specified power. It is chiefly question of the cost of coal.
 The existence of two simple laws makes electricity practical power for doing the worlds work. One is that when an armature is caused to rotate within the magnetic field a current of electricity is excited in the armature and may be taken up, carried out over a wire, and returned to the place of beginning This is what electricians call the law of the dynamo. The other : law is that when current of electrici- ty is passed through an armature in closed within the magnetic field the armature is caused to rotate. That is what electricians call the law of the motor. By the first law a current of electricity is set up, and by the second that current is enabled to establish mechanical motion. When these two laws became known the problem of applying electricity to the worlds work mainly needed for solution only a cheapening of processes, such as should make it possible to produce a current at commercial rates. Every dynamo, whatever it's form, as regards the communication of electric energy, is essentially an electro-Inagnet with a core of soft iron, the armature inclosed within the magnetic field, which is the space between the two poles of the electro-magnet. Every motor, what ever it's form, is essentially the same thing, with the core revolving under the influence of a current from the dy- namo in accordance with the law Cf the motor. The core of the dynamo, revolving under the influence of the magnetic field, is a shaft, the current generated is the belt communicating power to another shaft, the core of the motor. It is this transference of power by the invisible belt from the dynamo to the motor that makes the trolley cars run, the electrical engine revolve, or any other mechanism perform it's
 work under the influence of electricity thus generated. The storage battery is simply an isolated reservoir of elec. trical energy, for the time being inde- pendent of the generating source, as ii user of water should prefer to fill a tank in the top of his house once a week rather than to draw from faucets directly connected with the main source of supply.