Where an electric current is used for some simple device a thorough knowledge of electricity may not be necessary but if your invention requires that a low voltage current be changed into high frequency oscillations which are in turn varied by the voice and these oscillations are sent out from an aerial wire, all of which is done in a wireless telephone, I should say that you ought to have a pretty fair understanding of the theory of electricity before you begin your experiments—that is if you expect to develop your invention into an apparatus of utility and hence of worth.
Ideas for Electro-Mechanical Inventions.—There are many devices that are partly electrical and partly mechanical, the operation of the one actuating the other and the other way about.
Fig. 7. A FIRELESS COOKER. THE HEAT IS WHERE YOU WANT IT
The electric bell, see Fig. 9, and the telegraph sounder, see Fig. 10, are types of simple electro-mechanical devices, while the telautograph, see Fig. 11, and the electrical gyroscopic compass for use on ship-board, see Fig. 12, are examples of the more complex electro-mechanical devices.
To work out an idea by bringing both mechanics and electricity to bear in the same device often makes the work much easier for sometimes the armature of an electromagnet or the plunger of a solenoid will operate to a better advantage than a combination of levers. But to use mechanics and electricity in the same device you must of course have a knowledge of them both.
Ideas for Chemical Inventions.—There is another class of ideas which require neither mechanics nor electricity for their working out. They are chemical compounds.
Fig. 8. A LOUD SPEAKING TELEPHONE LARGELY USED ON SHIP-BOARD
Suppose an idea comes to you to make a chemical solution for erasing ink, or to make a new high explosive. While the idea might be a good one you would have a long road to travel if you began experimenting and had no knowledge of chemistry and your road in the latter case would probably be straight up.