The St. Johns herald., 1893-08-10
ELECTRICITY ON TAP.
The Potent Fluid Now Handed
 Like Any Merchandise.
Something About tIie Laws Which Con- trOl the Movements of the Won derful Power - Currents at
 Commercial Rates.

Electricity, once plaything, then a scientific st F, is now a commercial product. snty years ago electrical energy was generated in the labora- tory for experimental purposes by g few physicians as 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 manil1ins or pitch balls a-dancinS to the dynamo that runs from one to q 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 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 it may be served out over a wire in measured quantity, as gas and water are served through pipes. All this seems mysteri- 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 a 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 o1 splendid practical possi abilities. Now. with conditions given, a skilled cleo
 
 of producing the amount of electricity necessary to yield specified power. 1t is chiefly a question of the cost of coal.
 The existence of two simple laws makes electricity a practical power for doing the worlds work. One is that when an armature is caused to rotate within the magnetic field 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 clectrici- ty is passed through a1 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 current of electricity is set up, and by the second that current is enabled to establish mechanical motion. When these two applying electricity to the worlds work mainly needed for solution only a chcapening of processes, such as should make it possible to produce current at commercial rates. Every dynamo, whatever its form, as regards the communication of electric energy, is essentially an electro-magnet with a core of soft iron, the armatTIre incloscd within the magnetic field, which is the space between the two poles of the clectro-magnet. Every motor, what ever its 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 Of 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. 1t 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 its work under the influence of electricity thus generated. The storage battery is simply an isolated reservoir of cleo trical energy, for the time being inde- pendent of the generating source, as if a user of waler should prefer to fill a tank in the top of his house once week rather than to draw from faucets directly connected with the main source of supply.
 Wonders of the Insect World.
 EntOmOlOriStS generally cOpoade