CHAPTER IV

HOW TO EXPERIMENT

The kind of experimenting you will do will, of course, depend altogether on the nature of the invention on which you are working.

But, as good fortune would have it if you are not mechanically inclined you are not apt to hit upon a mechanical invention. And if you know nothing of electricity, you are not likely to think out an improved electrical device.

But this much is certain if you are going to experiment the right way you must know something about the right way to experiment. No one should expect to work out to a successful conclusion a new machine or apply a new improvement to an old machine if he knows nothing of the _first principles of mechanics_ or _about mechanical movements_, and by rights he ought to have some knowledge of _machine design_.

And the above statement is just as true of electrical inventions. A worker who does not know the difference between a binding post and an alternating current need not expect to progress very far with an invention of, say, an electric block signal system--unless he calls in an expert to help him; but what he should do is to study the principles of electricity and magnetism, learn the various currents that can be used and what apparatus and instruments are needed for utilizing these currents.

The same thing applies to inventions in chemistry in that to work intelligently you must know about the properties of substances, chemical change and acids, bases and salts. And with electro-chemistry both a knowledge of chemistry and electricity are needed.

It is easy to see that it would not be possible in the limited space I have here to say more than a word or two about the subjects of mechanics, electricity, chemistry and electro-chemistry when each requires a whole chapter to explain it even in a rough way and a whole book to explain it thoroughly. But there are a few things I can tell you about them that will put you on the right track and then I shall give you the names of some books that will be of great service to you when you are in need of them, and with your help we’ll make a real inventor of you.

~How to Experiment with Machines.--~Any one who possesses the slightest bent for mechanics can work out improvements on devices like egg-beaters and monkey-wrenches and feel their way as they go along.

But when it comes to designing and building real machines where numerous levers, gears, and springs are combined to make a working unit you should by all means read up on the subjects of _work, energy and power_, learn about the _six mechanical powers_--and the action of machines in general. The following definitions will give you an idea about all of them.

~Work, Energy and Power.--~A wheel will not turn of its own accord but if it is moved round by some _force_ applied to it such as the hand, a coiled spring or a motor, _work_ is done. In fact whenever a thing is made to change its position work is done.

The power to do work is caused by _energy_; energy is developed when some force is applied and can be stored up in bodies as when a ball is thrown. When the energy stops acting, or is used up, there can no longer be any work done. Energy can be _transferred_ from one body to another, as from a clock-spring to a wheel, or from one wheel to another wheel; and energy can be _transformed_, as the chemical energy of a battery into the rotary energy of a motor or from steam into mechanical motion.

The _unit of work_ is the _foot-pound_ and this is the work done to raise _one pound one foot high_. The _rate_ of doing work is the _horse power_ and a horse power is equal to lifting 550 foot-pounds in a second, or 33,000 foot-pounds in a minute.

Energy may be either _potential_ or _kinetic_; _potential energy_ means energy that is stored up and with nothing to act on, and for this reason it is called _energy of position_. The electric charge of a Leyden jar is potential energy but the moment it is released it makes a spark and becomes _kinetic energy_ or _energy of motion_. Potential energy can be changed into kinetic energy and kinetic energy back again into potential energy with amazing freedom. Energy has a definite relation to _velocity_ which means that when the speed of a moving body is increased its power to do work is also increased.

Like matter, energy cannot be destroyed, and so all of it taken together is called a _constant quantity_. When the energy stored up in a spring, or a battery, has been used the energy is not destroyed, though it may be very hard to find out where it has gone, but you may know that it has vanished in heat and in other forms of energy.

~Work Against Friction.--~The chief resistance which machines have to overcome is caused by _friction_. Since there is no such thing as a perfectly smooth surface friction is always present in machines and much energy must be spent in overcoming it. The energy wasted by friction is not destroyed but is transformed into another kind of energy and that is heat. When a marble is rolled over the surface of a table there is less friction between the two than when the marble slides across the table. Hence with _ball bearings_ there is less friction than with _cone bearings_. (See Appendix I.)

~Forms of Energy.--~There are nine forms of energy that you can make use of in your experiments and in your inventions, and these are:

{ Bodies in Motion--kinetic. { Bodies under Stress { ENERGY OF MASSES { (like a coiled spring). { Potential. { Bodies attracted by { { Gravitation. { { Sound--both kinetic and potential.

{ Heat. ENERGY OF MOLECULES { Molecular and Atomic Energy. AND ATOMS { Chemical Action.

ENERGY OF ETHER { Electric and Magnetic Actions. { Light and Invisible Radiation.

~Machines and the Principles of Machinery.--~A _machine_ is a contrivance of mechanical parts by which energy is transferred from one part to another. Beside the amount of energy required for doing useful work there must be an extra amount for overcoming the friction. Remember that no machine can either create energy or increase it, and, as you have seen, every machine wastes some energy in friction; this being true it must be clear then that it is impossible to make a machine which when once set in motion would continue to run forever, or at least until its parts were worn out. So don’t waste _your energy_ in trying to invent a _perpetual motion_ machine.

~The Uses of Machines.--~These are many and varied from a commercial point of view in that they are designed to do better, faster or cheaper work and sometimes all of these good qualities are found in a single machine.

From a mechanical point of view, though, a machine is used to

(1) Change one form of energy into another form, as steam into electricity.

(2) To make a slow moving, but powerful force produce a high speed or velocity, as in a sewing machine.

(3) To change a small, fast moving force into a powerful force, as in the action of a crowbar.

(4) To change the direction of a force so that the power can be applied where and when it is needed, and

(5) To make use of whatever force is at hand as the strength of animals, wind, water, steam, gas and electricity.

~The Six Mechanical Powers.--~As a matter of fact there are really only two of these, namely the _lever_ and the _inclined plane_, the other four, that is the _wheel_ and _axle_, the _pulley_, the _wedge_ and the _screw_ being simply modified forms of the first two.

The _lever_ is a rigid bar resting on, and which can be moved about a fixed point, called the _fulcrum_. There are three classes of levers and these are:

(1) Where the fulcrum is placed between the load and the power which moves it, as shown at A, Fig. 37; a pair of shears, pliers, a balance and a crowbar are levers of the first-class, see B, Fig, 37.

(2) Where the load is applied between the power and the fulcrum, as shown at A, Fig. 38; a lemon squeezer and wire splicing clamps are examples of this class; see B, Fig. 38, and

(3) Where the power is applied between the load and the fulcrum as shown at A, Fig. 39; the foot treadle of a jig saw and sugar tongs are levers of this class. See B, Fig. 39. Then there is the _bent lever_, as shown in Fig. 40, where the power and load do not act parallel with each other, and the _compound lever_ which takes the place of a single long lever as shown in Fig. 41, and which is used in large platform-scales.

The _wheel_ and _axle_ is really a form of lever and fulcrum. The axle provides a continuous fulcrum as shown in Fig. 42. Trains of wheel work, such as are used in clocks and other mechanical devices, are used to change a slow moving powerful force into a high speed, or velocity, or the other way about. Fig. 43 shows a train of wheel work.

The _pulley_ is a wheel with a cord, rope or belt running round it as shown in Fig. 44. It is used to transmit power and also to change the direction of it. A pulley can be either fixed or movable. A _compound pulley_ makes it possible to raise a heavy weight with a very small force, not by increasing the energy, but by transposing _velocity_ into _power_.

The _inclined plane_ is any hard smooth surface set at a slant to the force to be overcome. A barrel can be rolled up an inclined plane against the force of gravity, as shown in Fig. 45, while it could not be lifted straight up to the same height.

The _wedge_ is simply an inclined plane on a small scale. It is useful where a great force must be exerted through a small distance, as in splitting a stick of wood, as shown in Fig. 46.

A _screw_ is also a modified form of an inclined plane. By means of a screw great pressures can be exerted in a small space and here again a powerful force is had with a corresponding loss of velocity. It is shown in Fig. 47.

~Compound Machines.--~Any of the above six simple machines can be combined with any or all of the others and every machine that has ever been invented for any purpose is made up of a combination of these six mechanical powers.

Since the beginning of invention there has been made by combining these six mechanical powers in different ways, a large number of simple machines called _mechanical movements_; and there has not been a single new mechanical movement invented in many years.

Hence when you begin to work on your machine don’t waste time and energy trying to devise the mechanical movement you need, or what is still more foolish attempting to invent a new mechanical movement but look at the pictures in Fig. 48 which gives over 60 of the most useful mechanical movements. If you cannot find one among them that will do the work then look for it in Gardner D. Hiscock’s book of _Mechanical Movements_ which gives them all.

~Books.--~And it would be a good idea for you to read one of the following books which you can, most likely, get at any library:

_Elementary Physics_: Elroy M. Avery. _Elements of Physics_: Edwin J. Houston. _Elements of Physics_: George H. Hoadley. _College Physics_: A. L. Kimball.

The first-named books go deeply enough into the subject of physics for all ordinary purposes while the last named is very thorough and has a lot of _math_ in it; and all of them treat of liquids, air, electricity and magnetism, sound, heat and light. In whatever field you are working a general knowledge of physics will give you the key to a new and a mighty interesting world.

With the first principles of mechanics well in mind and the mechanical movements I have given, you can go on with your experiments in a safe and sensible way.

~How to Experiment with Electricity.--~_Electricity_ is very much like mechanics in that any one can put up an electric bell or screw in a plug-fuse but to experiment and build an apparatus in which electricity and magnetism are the powers used you must know how electricity is generated, how magnetism is produced, the different forms of electricity that are available and finally the kinds of apparatus best suited for the work that is required of them.

~Forms of Electricity.--~Though there is only one kind of electricity it can be divided into four classes, or forms, and these are:

(1) Electricity at rest, or _static electricity_, that is electricity stored up but not active as in a charged Leyden jar.

(2) Electricity in locomotion, or _current electricity_, in which electricity flows along wires, through solutions and other conductors when it is able to do work.

(3) Electricity in rotation, or _magnetism_ in which electric whirls produce attraction and repulsion, and:

(4) Electricity in vibration, or _radiation_ in which electric charges moving to and fro millions of times a second set up waves in the _ether_ which our eyes can see and which we call _light_. Then there are waves much too short for the eye to see and these are called _ultra-violet_ waves; there are waves too long for the eye to see and these are the _infra-red_ waves which we can feel for they are _heat_ waves, and finally there are very long waves set up in the ether by surging _high frequency_ currents in wires and these are called _electric_ or wireless waves.[2]

~Static Electricity.--~You can think of electricity as being a fluid, like water, for it has both _quantity_ and _pressure_, and in many ways it acts like a fluid.

If you filled a tank, raised above the ground, with water, the latter would be at rest, but it would be under pressure too and the moment a hole was bored in any part of the tank below the level of the water it would squirt out; in other words the _potential water_ would be changed into _kinetic_ water or water in locomotion. If, now, you charge a _Leyden jar_, or a _condenser_, with electricity it will be at rest until you bring the alternate coatings of tin-foil closely together when a spark will result and a current will flow.

Static electricity is generated by _friction_ and by _induction_, but the electricity so produced is very small in quantity and very high in pressure. A Leyden jar, or other condenser can be charged, though, with a low pressure current of electricity, as in a _spark coil_.

~Current Electricity.--~Whenever electricity flows in a wire, or other conductor, it acts like water flowing through a pipe and it is then called _current electricity_. The two most common ways to generate a current of electricity is by means of a _chemical battery_ and by a _dynamo electric machine_.

A current of electricity may have a small _current strength_, as its quantity is called, and a high _voltage_, as its pressure is called, like the discharge of a Leyden jar, or it may have a large current strength and a low voltage, as a current generated by a battery.

A _direct current_, see Fig. 49, is a current which flows steadily in one direction and this can be generated by a battery or a dynamo. An _interrupted current_, see Fig. 50, is a current that is _made_ and _broken_ a number of times a minute and this is usually done by a _vibrator_, or _interruptor_ as it is often called. A _pulsating current_, see Fig. 51, is one whose current strength is varied. One way to produce a pulsating current is to talk into a _telephone transmitter_ which is connected with a battery.

An _alternating current_, see Fig. 52, is one which flows first in one direction and then in the other direction. A _magneto-electric machine_ and an _alternating current generator_ are the means for generating this form of current. Alternating current can be produced from a direct current by using an _induction coil_, or _spark coil_ as it is called. But a steady direct current can be obtained from an alternating current only by coupling an _alternating current motor_ to a _direct current_ dynamo.

The pressure, or voltage, of an alternating current can be _stepped up_ or _stepped down_, that is, raised or lowered, by means of a _transformer_, which is the simplest form of induction coil. The current strength varies proportionately with the charges in pressure so that there can never be any increase in the total amount of energy but there is always a loss of energy due to heating and other causes. The moral again is that an electrically driven perpetual motion machine is a delusion and a snare. Alternating current can be changed into _interrupted direct current_, see Fig. 53, by an _electrolytic rectifier_ or a _mercury vapor tube_.

A _high tension current_ is an alternating current of sufficient pressure to make a _jump-spark_; it can be produced by a _high-tension magneto_, or a _spark coil_. An alternating current is generally considered one that changes its direction less than 100,000 times a second; when it changes its direction 100,000 times or more a second it is called an _oscillating current_, see Fig. 54, or a _high frequency current_, and this is the form of current that is used for sending out _wireless waves_.

The only known way to set up oscillating currents of really high frequency is by discharging the stored up electricity of a condenser, or its equivalent, through a circuit of small resistance by means of a spark, or an arc. The latter sets up sustained oscillations as shown in Fig. 55. _High frequency alternators_ (machines) have been built which generate alternating currents of over 100,000 _cycles_ per second.

~Magnetism.--~A bar of steel can be made magnetic by rubbing it on a _permanent steel magnet_ or on an _electromagnet_, or winding a number of turns of wire around it and passing a current through the wire.

If a bar of soft iron is placed in a coil of wire and a current is made to flow round it the iron will become a magnet but remains so only while the current is flowing, and this forms an _electromagnet_. An electromagnet works best on a direct current but an alternating current can also be used to energize it.

A coil of wire with an _air core_, that is without either an iron or a steel core, becomes a magnet when a current is made to flow through it. If, now, one end of a bar of soft iron is slipped into the hole in the coil of wire and the current is turned on the iron bar, or core, will be drawn into it. This kind of a magnet is called a _plunger electromagnet_, or _solenoid_.

~Radiation.--~Whenever you light a match, or make a light by any other means, electric charges on the molecules of the substance which is heated vibrate violently to and fro and the minute surgings of the electric charges set up _electro-magnetic_ waves in the _ether_ which the eye can see and the brain can sense and this is what we call _light_.

When some substances are intensely heated, as for instance, the _carbons_ of an _arc lamp_, waves are also sent out which are too short for the eye to see but which will nevertheless affect a photographic plate. These are called _ultra-violet waves_. The _infra-red_ waves are too long for the eye to see but the nerves of our bodies sense them as heat.

In conclusion take this bit of advice: don’t try to invent a new kind of electric current and don’t try to devise a new _electro-mechanical movement_ for in either case you will waste your time. Every form of current and every kind of electro-mechanical device you will need for any machine which you may invent are at hand and ready for use. Fig. 56 shows a number of electro-mechanical devices and these will aid you in getting the result you want.

~Books.--~The books on physics listed on page 69 go deeply enough into the subject of static and current electricity and magnetism for all ordinary purposes of invention, but if you are interested in _wireless_ and _high frequency electricity_ then I would suggest that you read the following books:

_The Book of Wireless._ A. F. Collins. _Manual of Wireless Telegraphy._ A. F. Collins. _Wireless Telegraphy and High Frequency Electricity._ H. LaV. Twining. _Electric Wave Telegraphy._ J. A. Fleming.

~Your Electrical Equipment.--~Should your invention call for experiments in electricity, especially where the amount of current used is a factor, you should provide yourself with a good _ammeter_, as shown in Fig. 57, for measuring the current in _amperes_, and a _volt meter_, as shown in Fig. 58, for measuring the pressure, or _voltage_, in _volts_. (See Appendix O.)

Where the resistance in _ohms_ of a wire, or a circuit of any kind must be known a _combined bridge and resistance box_ is the best way to make accurate measurements. Resistance boxes measuring from .001 ohm to 17.600 ohms can be bought of the L. E. Knott Apparatus Co., Boston, Mass., for about $18.00. It is shown in Fig. 59.

A large number of electrical devices call for winding wire on cores, spools, coils, etc. Nearly all windings can be done on a lathe but if a lathe is not among your treasured possessions you can make a _winder_ which will serve all ordinary purposes. The drawings shown at A and B, Fig. 60, give all the details of construction and you can make one chiefly of wood of whatever size your winding calls for.

~How to Experiment with Chemistry.--~It is a pleasant pastime to make chemical experiments after a known formula but it is quite a different and a difficult thing to try to invent some new chemical compound when you know little or nothing of chemistry.

If your invention calls for some _chemical combination_ or _decomposition_ or _double decomposition_--these are the three kinds of chemical action--get an elementary book on chemistry and study it until you really know it and then you will have a bed-rock foundation on which to build up your invention.

You may say it is all very well to read a book on chemistry and learn all about it but it’s a mighty hard thing to do without a teacher. My answer is if you are not interested in chemistry, you will certainly find the study of it up-hill work and very tedious.

But if you are working on an invention like, say, _synthetic gems_, that is making real rubies and sapphires and emeralds in an oxy-hydrogen furnace, see Fig. 61, you will not only study but you will study harder than you have ever studied before if you believe it will help you to find the solution of the gem problem. It is under these conditions that work-study becomes play-study and you will be fascinated with it and it will then prove pleasant as well as profitable.

~Your Chemical Equipment.--~The chemical apparatus you will require depends entirely on the class of work you are doing but for all ordinary chemical experiments the following apparatus will be found useful: (1) a nest of beakers; (2) a jeweler’s blowpipe; (3) one-half dozen wide mouth flint bottles; (4) a Bunsen burner with regulator, that is if you have gas, or (5) an alcohol lamp; (6) a glass U tube; (7) a nest of Hessian crucibles; (8) a nest of porcelain crucibles; (9) an evaporating dish; (10) a lead dish; (11) a couple of glass funnels; (12) a glass bottle with a two hole stopper; (13) half a pound of glass tubing; (14) a porcelain mortar and pestle; (15) a plain glass retort; (16) a stoppered retort; (17) 3 or 4 feet of ¼ inch rubber tubing; (18) a sand bath; (19) a dozen test tubes; (20) a test-tube stand; (21) a test-tube clamp; (22) a test-tube brush; (23) an iron retort tripod; (24) one-half dozen watch glasses; (25) a water bath; (26) some wire clamp supports; (27) a couple of platinum plates; (28) an air bath; (29) a burette; (30) a pinch-cock, and (31) a brass scale with weights. See Fig. 62.

All of the above apparatus can be bought of any dealer in chemical or school apparatus for ten or twelve dollars. For advanced work you will need other apparatus but whatever your requirements may be you can either buy the apparatus ready made or have it made to order.

As to chemicals these will likewise depend on the nature of your experiments. Send to Eimer and Amend, 205 Third avenue, New York City, for a catalogue and price list of chemicals and chemical apparatus as they sell everything used by chemists and electrochemists.

~Books.--~The following books with the exception of the last one are good elementary treatises on chemistry:

1.--_Elementary Chemistry._ Smith. 2.--_First Principles of Chemistry._ Brownlee. 3.--_Chemistry._ Remsen. 4.--_Complete Chemistry._ Avery.

~How to Experiment with Electro-Chemistry.--~In working out electro-chemical inventions you require a knowledge of both electricity and chemistry for it is the electric current that produces the chemical change either directly or indirectly.

An electric battery of any kind is electro-chemical in action and so is _electroplating_ and _electrotyping_ but these are old inventions. The production of _ozone_ and _nitric acid_ from the air by the action of an electric spark; of coal tar colors by _electrolysis_; the _electrolytic_ refining of copper and the electrolytic production of aluminum are electro-chemical inventions in which the action of the electric current is direct. And they are inventions of great importance and of recent date.

Then there are a large number of indirect electro-chemical processes in which the electric current is used to produce heat as in the electric furnace. Genuine diamonds, though too small and too costly to have any commercial value, have been made in the electric furnace, shown in Fig. 63. _Calcium carbide_ for making acetylene gas; _carborundum_, an abrasive that is better than emery; _electric smelting_ and the _reduction_ of _iron ore_ with carbon are all new electric furnace inventions of great value, and there are many others.

BOOK.

_The Elements of Electro-Chemistry Treated Experimentally._ By Lüpke.