Chapter XV: The Energy of the Sun, and How Heat Is Measured

In the first chapter we tried to give a clear view of the prime factors necessary to develop motion. The boy must thoroughly understand the principles involved, before his mind can fully grasp the ideas essential in the undertaking.

While the steam engine has been the prime motor for moving machinery, it is far from being efficient, owing to the loss of two-thirds of the energy of the fuel in the various steps from the coal pile to the turning machinery.

_First_, the fuel is imperfectly consumed, the amount of air admitted to the burning mass being inadequate to produce perfect combustion.

_Second_, the mechanical device, known as the boiler, is not so constructed that the water is able to completely absorb the heat of the fuel.

_Third_, the engine is not able to continuously utilize the expansive force of the steam at every point in the revolution of the crankshaft.

_Fourth_, radiation, the dissipation of heat, and condensation, are always at work, and thus detract from the efficiency of the engine.

The gasoline motor, the next prime motor of importance, is still less efficient in point of fuel economy, since less than one-third of the fuel is actually represented in the mechanism which it turns.

The production of energy, in both cases, involves the construction of a multiplicity of devices and accessories, many of them difficult to make and hard to understand.

To produce power for commercial purposes, at least two things are absolutely essential. First, there must be uniformity in the character of the power produced; and, second, it must be available everywhere.

Water is the cheapest prime power, but its use is limited to streams or moving bodies of water. If derived from the air currents no dependence can be placed on the regularity of the energy.

Heat is the only universal power on the globe. The sun is the great source of energy. Each year it expends in heat a sufficient force to consume over sixty lumps of coal, each equal to the weight of the earth.

Of that vast amount the earth receives only a small part, but the portion which does come to it is equal to about one horse power acting continuously over every thirty square feet of the surface of our globe.

The great problem, in the minds of engineers, from the time the steam engine became a factor, was to find some means whereby that energy might be utilized, instead of getting it by way of burning a fuel.

One of the first methods proposed was to use a lens or a series of mirrors, by means of which the rays might be focused on some object, or materials, and thus produce the heat necessary for expansion, without the use of fuel.

Wonderful results have been produced by this method; but here, again, man meets with a great obstacle. The heat of the sun does not reach us uniformly in its intensity; clouds intervene and cut off the rays; the seasons modify the temperature; and the rotation of the globe constantly changes the direction of the beams which fall upon the lens.

The second method consists in using boxes covered with glass, the interior being blackened to absorb the heat, and by that means transmit the energy to water, or other substances adapted to produce the expansive force.

Devices of this character are so effective that temperatures much above the boiling point of water have been obtained. The system is, however, subject to the same drawbacks that are urged against the lens, namely, that the heat is irregular, and open to great variations.

These defects, in time, may be overcome, in conserving the force, by using storage batteries, but to do so means the change from one form of energy to another, and every change means loss in power.

The great problem of the day is this one of the conversion of heat into work. It is being done daily, but the boy should understand that the _direct conversion_ is what is required. For instance, to convert the energy, which is in coal, into the light of an electric lamp, requires at least five transformations in the form of power, which may be designated as follows:

1. The burning of the coal.

2. The conversion of the heat thus produced into steam.

3. The pressure of the steam into a continuous circular motion in the steam engine.

4. The circular motion of the steam engine into an electric current by means of a dynamo.

5. The change from the current form of energy to the production of an incandescent light in the lamp itself, by the resistance which the carbon film offers to the passage of the current. Should an inventor succeed in eliminating only one of the foregoing steps, he would be hailed as a genius, and millions would not be sufficient to compensate the fortunate one who should be able to dispense with three of the steps set forth.

The Measurement of Heat.--To measure heat means something more than simply to take the temperature. As heat is work, or energy, there must be a means whereby that energy can be expressed.

It has been said that the basis of all true science consists in correct definitions. The terms used, therefore, must be uniform, and should be used to express certain definite things. When those are understood then it is an easy matter for the student to grope his way along, as he meets the different obstacles, for he will know how to recognize them.

Before specifically explaining the measurement it might be well to understand some of the terms used in connection with heat. The original theory of heat was, that it was composed of certain material, although that matter was supposed to be subtle, imponderable and pervading everything.

This imponderable substance was called _Caloric_. It was supposed that these particles mutually attracted and repelled each other, and were also attracted and repelled by other bodies, so that they contracted and expanded.

The phenomenon of heat was thus accounted for by the explanation that the expansion and contraction made the heat. This was known as the _Material Theory of Heat_.

But that phase of the explanation has now been abandoned, in favor of what is known as the _dynamical_, or _mechanical_ theory, which is regarded merely as a _mode_ of _motion_, or a sort of vibration, wherein the particles move among each other, with greater or less rapidity or in some particular manner.

Thus, the movements of the atoms may be accelerated, or caused to act in a certain way, by friction, by percussion, by compression, or by combustion. Heat is the universal result of either of those physical movements.

Notwithstanding that the material theory of heat is now abandoned, scientists have retained, as the basis of all heat measurements, the name which was given to the imponderable substance, namely, _Caloric_.

It is generally written _Calorie_, in the text books. A calorie has reference to the quantity of heat which will raise the temperature of one kilogram of water, one degree Centigrade.

As one kilogram is equal to about two pounds, three and a quarter ounces, and one degree Centigrade is the same as one and two-thirds degrees Fahrenheit, it would be more clearly expressed by stating that a caloric is the quantity of heat required to raise the temperature of one and one-fifth pound of water one degree Fahrenheit.

This is known as the scientific unit of the thermal or heat value of a caloric. But the engineering unit is what is called the British Thermal Unit, and designated in all books as B. T. U.

This is calculated by the amount of heat which is necessary to raise a kilogram of water one degree Fahrenheit. According to Berthelot, the relative value of calorics and B. T. U. are as follows:

HEATS OF COMBUSTION

---------------------------------------------------
_Substance._ _Calories._ _B. T. U._
---------------------------------------------------
Hydrogen 34,500 62,100
Carbon to carbon dioxide 8,137 14,647
Carbon to carbon monoxide 2,489 4,480
Carbon monoxide 2,435 4,383
Methane 13,343 24,017
Ethylene 12,182 21,898
Cellulose 4,200 7,560
Acetylene 12,142 21,856
Peat 5,940 10,692
Naphthalene 9,690 10,842
Sulphur 2,500 4,500

When it is understood that heat is transmitted in three different ways, the value of a measuring instrument, or a unit, will become apparent.

Thus, heat may be transmitted either by _conduction_, _convection_, or _radiation_.

_Conduction_ is the method whereby heat is transmitted from one particle to another particle, or from one end of a rod, or other material to the other end. Some materials will conduct the heat much quicker than others, but if we have a standard, such as the calorie, then the amount of heat transmitted and also the amount lost on the way may be measured.

_Convection_ applies to the transmission of heat through liquids and gases. If heat is applied to the top or surface of a liquid, the lower part will not be affected by it. If the heat is applied below, then a movement of the gas or liquid begins to take place, the heated part moving to the top, and the cooler portions going down and thus setting up what are called _convection currents_.

_Radiation_ has reference to the transference of heat from one body to another, either through a vacuum, the air, or even through a solid.

By means of the foregoing table, which gives the heats developed by the principal fuels, it is a comparatively easy matter to determine the calorific value of fuels, which is ascertained by making an analysis of the fuel.

The elements are then taken together, and the table used to calculate the value. Suppose, for instance, that the analysis shows that the fuel has seventy-five per cent. of carbon and twenty-five per cent. of hydrogen. It is obvious that if we take seventy-five per cent. of 8,137 (which is the index for carbon), and twenty-five per cent. of 43,500 (the index of hydrogen), and adding the two together, the result, 14,727, would represent the calorific value of the fuel.

GLOSSARY OF WORDS

USED IN TEXT OF THIS VOLUME

=Absolute.= Independent; free from all limitations.

=Amplitude.= Greatness of extent; the state or quality
of being sufficient.

=Absorbent.= A material which will take up a liquid.

=Absorbing.= Taking up, or taking in.

=Absorption.= The act or process of taking up or fully
occupying.

=Abutment.= A wall; a stop.

=Accuracy.= Correctness; positiveness.

=Accession.= Added to; addition, or increase.

=Accelerate.= Quickened; hurried.

=Accessible.= Available; capable of being reached.

=Accelerated.= A quickening, as of process or action.

=Actuating.= Moved or incited by some motive.

=Advance Spark.= The term applied to the movement of
the mechanism in an internal combustion
engine, which will cause the electric
spark to act before the crank has
passed the dead center.

=Aeration.= To add air; to impregnate with oxygen.

=Alkali.= In chemistry it is known as a compound of
hydrogen and oxygen, with certain
chemicals. Anything which will
neutralize an acid.

=Allusion.= Referring to; noticed.

=Anomaly.= A deviation from an ordinary rule; irregular.

=Adhesion.= To cling to; to stick together.

=Adjustment.= To arrange in proper order; to set into
working condition.

=Alternating A current which goes back and
current.= forth in opposite directions; unlike a
direct current which flows continuously
in one direction.

=Ampere.= The unit of current; the term in which
strength of current is measured. An
ampere is an electromotive force of one
volt through a resistance of one ohm.

=Amplitude.= The state or quality of being broad, or full.

=Analysis.= The separation into its primitive or
original parts.

=Annular.= Pertaining to or formed like a ring.

=Armature.= The part of a dynamo or motor which
revolves, and on which the wire coils
are wound.

=Assuming.= Taking on; considered to be correct or
otherwise.

=Asphaltum.= A bituminous composition used for
pavements, properly made from natural
bitumen, or from asphalt rock.

=Atmospheric.= Referring to; noticed.

=Available.= Capable of being employed or used.

=Bearings.= The part in mechanism in which journals or
spindles rest and turn.

=Bifurcated.= In two parts; branching, like a fork.

=Blow-off valve.= A valve so arranged that at certain
pressures the valve will automatically
open and allow the steam to escape from
the boiler.

=Bombard.= An assault; an attack by shot or shell.

=Bonnet.= The cap of a valve, which is so arranged
that while it permits the valve stem to
turn, will also prevent leakage.

=Butterfly-valve.= A form of valve which is usually flat,
and adapted to open out, or turn
within the throat or pipe.

=Caloric.= Pertaining to heat.

=Cam.= A rotating wheel, or piece, either regular or
irregular, non-circular, or eccentric.

=Carbon.= A material like coke, ground or crushed. It
required high heat to burn it, and it
is used for the burning material in
electric arc lamps.

=Carbureter.= The device used to mix air and gaseous
fuel in an internal combustion engine.

=Carbonized.= Put into a charred form; coke is carbonized
coal; charcoal is carbonized wood.

=Carbureted.= Air or gas to which has been added the
gaseous product of petroleum, or some
distillate.

=Centripetal.= That which draws inwardly, or to the
center, like the gravitational action
of the earth.

=Centrifugal.= That which throws outwardly; the
opposite of centripetal.

=Check valve.= A form of valve which will permit
liquids to freely flow in one
direction, but which will open
automatically, so as to allow the
liquid to flow in the opposite
direction.

=Chemical.= Pertaining to the composition of matter;
or relating to chemistry.

=Chambered.= Having compartments, or divided up into
recesses.

=Circumference.= Around the outside.

=Circularly.= Around; about the circumference.

=Circulation.= The movement of water to and fro
through conduits.

=Clearance.= The space at the head of a cylinder
within which the steam or gases are
compressed by the piston.

=Classification.= To put in order in a systematic way.

=Coincide.= To correspond with identity of parts.

=Cohesion.= To stick together. The attraction of
material substances of the same kind
for each other.

=Coöperate.= To work together harmoniously.

=Compounding.= Composed of or produced by the union of
two or more parts, or elements.

=Complicated.= Very much involved; not simple.

=Commutator.= The revolving part on the armature of a
dynamo or motor, which is divided up
into a multiplicity of insulated
plates, which are connected with the
coils of the wire around the armature.

=Combustion.= Burning; the action of the unity of
oxygen with any substance, which causes
it to be destroyed or changed.

=Commodity.= Any product, or kind of goods.

=Concaved.= Hollowed.

=Condensation.= The change from a gaseous to a liquid
or solid state.

=Condenser.= An apparatus which converts a gas into a
liquid.

=Concentric.= A line which at any point is at the same
distance from a common center.

=Conductor.= A substance which will convey either heat
or electricity from one end to the
other.

=Conical.= In the form of a cone.

=Conically.= In the form of a cone.

=Conduit.= A trough, tube, or other contrivance, which
will convey liquids or gases from place
to place.

=Conduction.= The capacity to transmit from one point
to another.

=Connecting Rod.= That part of mechanism which
connects the piston rod with the crank.

=Conserve.= To take care of; to use judiciously.

=Constant.= Being the same thing at all times; not
varying.

=Contrivance.= Any mechanism, or device which will
serve a certain purpose.

=Contra- That which is opposite to,
distinction.= comparatively; taken in conjunction
with for the purpose of comparison.

=Cornish.= A form of boiler which has the fire tubes
within the water space.

=Contact Breaker.= A device which has the current
normally in circuit, and is so arranged
that the circuit is broken at certain
intervals, and again immediately
reëstablished.

=Co-relate.= Belonging to; having reference to the
same order.

=Conventional.= The regular manner or method.

=Contact Maker.= A device for making contacts in an
electric circuit at regular intervals.

=Convolution.= The turns or twists taken. The changes
or movement or the peculiar flow of a
liquid.

=Control.= Handling with regularity; The act of
guiding.

=Contracted.= Made smaller.

=Contingency.= An event; under certain conditions.

=Counteract.= To antagonize; to so act as to go
against.

=Converting.= Changing; to put in an opposite condition.

=Cylindrical.= In the form of a cylinder;
barrel-shaped.

=Cyclopedia.= A work which gives, in alphabetical order,
the explanations of terms and subjects.

=Cycle.= A period extending over a certain time; a
certain order of events.

=Dead Center.= That point in the turn of a crank where
the piston has no effective pull in
either direction.

=Deënergize.= To take power away from.

=Deflecting.= To glance off; to change the regular or
orderly course.

=Demagnetized.= To take magnetism away from.

=Deterioration.= To take away from; to grow smaller;
to lessen; to depreciate in quality.

=Deviate.= To avoid; to get around; not going or doing
in the regular way.

=Diagram.= A mechanical plan or outline, as
distinguished from a perspective drawing.

=Diametrically.= Across or through the object; through
the center.

=Dioxide.= An oxide containing two atoms of oxygen to
the molecule.

=Direct current.= An electric current which flows
continuously in one direction.

=Dissipated.= Changed, or entirely dispensed with;
usually applied to a condition where
materials or substances are scattered.

=Distributer.= A piece of mechanism in an electric
circuit, which switches the current
from one part to the other.

=Dissect.= To take apart.

=Dominating.= Overpowering; having greatest power.

=Diverse.= Different; unlike.

=Dry Cell.= A battery in which the electrolyte is not
in a fluid state.

=Duct.= Either an open trough or conduit, or a closed
path for the movement of gases or liquids.

=Dynamo.= A mechanical device for the purpose of
generating electricity.

=Eccentric.= A wheel having its perimeter so formed
that the center is not in the exact
middle portion.

=Economy.= Prudence; carefulness; not disposed to be
excessive.

=Efficiency.= Well adapted for the situation;
mechanism which will do the work
perfectly, or cheaply.

=Effectiveness.= Well done; to the best advantage.

=Ejecting.= Throwing out; sending forth.

=Elastic.= That quality of material which tends to
cause it to return to its original
shape when distorted.

=Elementary.= Primitive; the first; in the simplest
state.

=Electric arc.= A term applied to the current which
leaps across the slightly separated
ends of an electric conductor.

=Electricity.= An agent, incapable of being seen, but
which produces great energy.

=Electrolyte.= The agent, or material in a battery,
usually a liquid, which the current
passes through in going from one
electrode to the other.

=Elliptical.= A form which might be expressed by the
outline shape of an egg, measured from
end to end.

=Emolument.= Pay; remuneration; the amount received
for employment of any kind.

=Emission.= To send out from; a sending or putting out.

=Energy.= Force; power.

=Essential.= The main thing; the important element.

=Evaporate.= To convert into vapor, usually by heat.

=Exhaust.= The discharge part of an engine, or other
apparatus.

=Excessive.= Too much; more than is required.

=Expansion.= Enlarged; the occupying of a greater space.

=Explicit.= Particularly definite; carefully explained
and understood.

=External.= Outside; the outer surface.

=Facilitating.= Helping; aiding in anything.

=Factor.= An element in a problem.

=Fahrenheit.= One of the standards of heat
measurement. A thermometer scale, in
which the freezing point of water is
32, and the boiling temperature is 212.

=Fascinating.= Attractiveness; capacity to allure.

=Feathered.= Applied to the shape of an article, or to
a rib on the side of a shaft, which is
designed to engage with a groove.

=Fertilizer.= Material for enriching soil and
facilitating the growth of vegetables.

=Field.= A term applied to the windings and the pole
pieces of a dynamo or motor, which
magnetically influence the armature.

=Focal.= The point; the place to which all the
elements or forces tend.

=Foot pounds.= The unit of mechanical work, being the
work done in moving one pound through
a distance of one foot.

=Four-cycle.= A gasoline engine, in which the ignition
of the compressed hydro-carbon gases
takes place every other revolution.

=Formation.= The arrangement of any mechanism, or a
series of elements.

=Formula.= The recipe for the doing of a certain
thing; a direction.

=Friction.= A retarding motion; the prevention of a
free movement.

=Function.= The qualities belonging to an article,
machine or thing; that which a person
is capable of performing.

=Fundamental.= The basis; the groundwork of a thing.

=Gaseous.= Of the nature of a gas.

=Gearing.= Usually applied to two or more sets of
toothed wheels which coöperate with
each other.

=Generating.= Producing; manufacturing; bringing out of.

=Globules.= The small particles of liquids; or the
molecules comprising fluids.

=Gravitation.= The force of the earth which causes all
things to move toward it; the
attraction of mass for mass.

=Heart Wheel.= A wheel having the outline of a heart.

=Helical.= A spirally-wound form.

=High Tension.= A term applied to a current of
electricity, which has a very high
voltage, but low amperage.

=Horizontal.= Level, like the surface of water; at
right angles to a line which points to
the center of the earth.

=Horse Power.= The unit of the rate of work, equal to
33,000 pounds lifted one foot in one minute.

=Hydro-carbon.= A gas made from the vaporization of
crude petroleum or of its distillates.

=Hydrogen.= One of the original elements. The lightest
of all gases.

=Ignite.= To set on fire.

=Ignition.= The term applied to the firing of a charge
of gas in a gas or gasoline engine.

=Impact.= A blow; a striking force.

=Impregnated.= To instill; to add to.

=Impulse.= A natural tendency to do a certain thing;
determination to act in a certain way
through some influence.

=Impinge.= To strike against; usually to contact with
at an angle.

=Incomparable.= Too good or great to measure.

=Inclined.= Not level; leaning; not horizontal.

=Induction.= The peculiar capacity of an electric
current to pass from one conductor to
another through the air.

=Indication.= That which shows; to point out.

=Injector.= A device whereby the pressure of the steam
in a boiler will force water into the
boiler.

=Initially.= At first; the original act.

=Injection.= To put into; to eject from an apparatus,
into some other element.

=Insulated.= So covered as to prevent loss of current
by contact with outside substances or
materials.

=Intimate.= Close to; on good terms with.

=Integral.= A complete whole; containing all the parts.

=Instinct.= Knowledge within; something which
influences conduct or action.

=Interstellar.= The space beyond the earth; that portion
of the heavens occupied by the stars.

=Internal.= Within; that portion of mechanism which is
inside.

=Interposing.= To step into; to place between, or in
the midst of.

=Intensity.= Fierce; strong; above the ordinary.

=Interrupted.= To stop; to take advantage of.

=Interstices.= The spaces in between.

=Instantaneous.= Immediately; at once; without waiting.

=Intricate.= Difficult; not easy.

=Inquisitive.= The desire to inquire into.

=Jacketing.= To coat or cover on the outside.

=Jump Spark.= One of the methods of igniting
hydro-carbon gases. A current of
sufficiently high voltage is used to
cause the current to jump across the
space between the separated ends of a
conductor.

=Kinetic.= Consisting in or depending on motion.

=Latent.= That which is within itself.

=Lateral.= Branching out from the sides; usually
applied as the meaning for the
direction which is at right angles to a
fore and aft direction.

=Lines of force.= Applied to electricity, air, water,
or any moving element, which has a well
directed movement in a definite
direction.

=Low Tension.= In methods for igniting hydro-carbon charges,
any circuiting which has a low voltage.

=Lubrication.= The oiling of mechanical parts to
reduce friction.

=Mangle.= A machine for smoothing out clothing, goods,
etc.

=Magneto.= A dynamo which has the field pieces, or
poles made of permanent magnets.

=Magnetism.= That quality, or agency by virtue of
which certain bodies are productive of
magnetic force.

=Manifestation.= Showing or explaining a state of
things; an outward show.

=Make and Break.= An ignition system, which provides
for throwing in and cutting out an
electric circuit.

=Manifold.= A system of piping whereby the exhausts of
a gasoline engine are brought together
into one common discharge.

=Manganese.= A hard, brittle, grayish white metallic
element, used in the manufacture of
paints and of glass, and also for
alloying metals.

=Manually.= Doing things by hand; muscular activity.

=Material.= Substances and parts from which articles
are made.

=Mechanically.= Doing things by means of machinery, or
in some regular order.

=Mobility.= The capacity to move about.

=Multiple.= A figure used a certain number of times,
is said to be a multiple of a number,
if it will divide the number equally.
Thus 4 is a multiple of 16; 3 is a
multiple of 9, and so on.

=Neutral.= Neither; not in favor of any party or
thing.

=Normal.= As usual; in the regular way; without
varying from the ordinary manner.

=Ohm's Law.= In electricity, it is expressed as
follows: 1. The current strength is
equal to the electromotive force
divided by its resistance. 2. The
electromotive force is equal to the
current strength multiplied by the
resistance. 3. The resistance is equal
to the electromotive force divided by
the current strength.

=Oscillating.= Moving to and fro, like a pendulum.

=Orifice.= An opening; a hole.

=Organism.= Any part of the body, or any small germ or
animalcule.

=Oxidation.= The action of air or oxygen on any
material, is called oxidation. Thus
rust on iron is called oxidation.

=Oxygen.= A colorless, tasteless gas, the most
important in nature, called the
acid-maker of the universe, as it
unites with all substances, and
produces either an acid, an alkali, or
a neutral compound.

=Parallel.= Two lines are said to be parallel, when
they are lying side by side and are
equally distant from each other from
end to end.

=Pendulum.= A bar suspended at one end to a pivot pin,
and having its lower end free to swing
to and fro.

=Penstock.= A reservoir designed to receive and
discharge water into a turbine or other
form of water wheel.

=Permanent.= That which will last; not easily stopped.

=Pestle.= An implement of stone or metal used for
breaking and grinding up chemicals, and
other material in a mortar.

=Petroleum.= A liquid fuel product, found in many
places, its component parts being about
15 per cent. hydrogen and 85 per cent.
carbon.

=Perimeter.= The outer rim, or circle.

=Piston.= That part of an engine which is attached to
the piston rod.

=Pinion.= A small gear wheel driven by a larger gear
wheel.

=Platinum.= An exceedingly hard metal, used in places
for electrical work where the current
is liable to burn out ordinary
conductors.

=Polarity.= The quality of having opposite poles.

=Pre-heating.= To heat before the ordinary process of
heating commences.

=Ponderous.= Large; heavy; difficult to handle.

=Port.= In nautical parlance the left side of a
vessel; the larboard side; also an
opening, or a conduit for the
transmission of gas or liquid.

=Pop valve.= A valve designed to open and allow escape
of the imprisoned gases when the latter
reach a certain pressure.

=Potential.= The power; the term used in electricity
to denote the energy in a motor.

=Plurality.= More than one; many.

=Precipice.= A high and very steep cliff.

=Pressure.= The act of one body placed in contact with
another and acting against it or
against each other.

=Precaution.= Taking great care; being assured of safety.

=Primary A cell, or a number of cells, made
battery.= of pairs of metallic couples, immersed
in an electrolyte of either an acid or
an alkali.

=Proney Brake.= A device for testing machinery and
determining power, by means of
friction.

=Primeval.= The earliest; the first; of a low order.

=Proportion.= The relation of one thing or number, to
another; comparative merit.

=Proximity.= Close to; near at hand.

=Quadruple.= Four times.

=Rack.= A bar having a number of teeth, to serve as a
step or measure for a pawl, or a
toothed wheel.

=Radial.= Extending out from the center.

=Radiation.= The property of many substances to give
forth heat or cold, or to disperse it.

=Rarified.= Made less than the normal pressure, as
air, which is not as dense at a high as
at a low altitude.

=Receiver.= In telephone apparatus, that part of the
mechanism which transmits the message
to the ear.

=Rectilinear.= A right line; a straight direction
forwardly.

=Reaction.= A force which is counter to a movement in
another direction.

=Refrigeration.= Cooling process; the art of freezing.

=Refined.= Purifying; improved.

=Re-heating.= The process of further heating or
increasing the temperature during the
progress of the work.

=Requisite.= The necessary part; the requirement.

=Residue.= The balance; what is left over.

=Resistance.= Opposition; against.

=Reciprocating.= One for the other; moving from one
side to the other.

=Refinement.= Chastity of thought, taste, manner, or
actions.

=Retort.= A vigorous answer. A receptacle adapted to
stand a high heat.

=Revolution.= Turning, like the earth in its orbit.

=Rock Shaft.= A shaft which turns part of its rotation
in one direction, and then turns in the
other direction.

=Rotation.= The turning of a wheel on its axle; the
rotation of the earth on its axis each
day. Distinguishing from revolution
which is a swinging of the entire body
of the earth around the sun in its orbit.

=Sal-Ammoniac.= A white metallic element.

=Scavenging.= To clean out; to scour.

=Secondary A battery which is charged with a
Battery.= current, and then gives forth an
electric current of a definite amount.
It is also known as an _accumulator_,
since its elements continue to
accumulate electric energy.

=Secondary coil.= In induction coils two wire
wrappings are necessary, the first
winding being, usually, of heavy wire,
and called the primary; the second
winding is of finer wire, and is called
the secondary coil.

=Sector.= An A-shaped piece cut from a disk;
distinguish this from a segment, which
is a part cut off from a disk by a
single straight line.

=Secondary.= Occupying a second place; not of the
first kind, or place.

=Segment.= A part cut off from a disk, by a single
line; the part of a circle included
within a chord and its arc.

=Sewerage.= The conveyance of waste matter from a
building.

=Sinuous.= Systematic draining by means of pipes or
conduits. Characterized by bends, or
curves, or a serpentine curving, or
wave-like outline.

=Slide Valve.= A form, which moves along a flat
surface through which the duct is formed.

=Solution.= A liquid having therein different
substances mixed together.

=Sprayer.= To eject; to send forth in small particles.

=Stability.= Fixed; strength to stand without support.

=Stupendous.= Immense; large; much beyond the largest
of the kind.

=Standard.= A sample of the measure or extent; a type
or a model.

=Stratify.= To deposit, form, or range in strata.

=Super Heating.= To heat up beyond the ordinary or
normal point.

=Subtle.= Crafty; made of light material; daintily
constructed.

=Supersede.= In place of; to take the place of.

=Susceptible.= Capable of being changed or influenced.

=Suspension.= Hanging; floating of a body in fluid.

=Suction.= The production of a partial vacuum in a
space connected with a fluid under
pressure.

=Terminal.= The end; the last part.

=Technical.= Specially or exclusively pertaining to
some art or subject.

=Theoretical.= That which is speculative, as
distinguished from practical.

=Throttle Valve.= A device which is designed to cut
off the flow of a fluid.

=Throttling.= The closing of a port; the cutting down
of a supply.

=Transformation.= A complete change; made over into
something else.

=Transmit.= To convey; to send to another part.

=Transference.= To convey to another part; the change
from one thing to another.

=Transferred.= Put over.

=Triple.= Three; thrice.

=Turbine.= To turn; a form of water wheel and steam
engine, where the fluid impinges
against the blades arranged around the
perimeter of the wheel.

=Tubular.= Hollowed; like a pipe.

=Two-Cycle.= A gasoline engine, in which the
compressed hydro-carbon gases are fired
every turn of the crank shaft.

=Typical.= The nature or characteristics of a type.

=Undershot.= A type of wheel in which the water shoots
past and against the blades on the
lower side.

=Unison.= Together; conjointly; acting with each
other.

=Universally.= All over the world; throughout all
space.

=Utility.= Use; that which is valuable or of service.

=Vacuum.= That part from which all material is taken;
in a limited sense, air, which has less
density than the normal.

=Vaporizing.= To convert into gas, usually by heat.

=Variable.= With differing characteristics; changeable.

=Venturi Tube.= A form of tube which has a contracted
part between its ends.

=Vertical.= In the direction of a line which points to
the center of the earth.

=Vibrator Coil.= In electrical devices used in the
ignition systems of certain types of
gasoline engines, a winding is provided
on a metallic core, which has an
armature that is made so it will vibrate.

=Volt.= The pressure of an electric current; the unit
of electromotive force.

=Voltage.= Electromotive force as expressed in volts.

=Volt Meter.= An instrument for indicating the voltage
of an electric circuit.

=Watt.= The electrical unit of the rate of working in
an electric circuit, the rate being the
electromotive force of one volt, and
the intensity of one ampere.

=Weight.= The measure of the force toward the center
of the earth, due to gravity.

=Winnowed.= Taken out; sifted from.

=Wiping Bar.= A metallic piece which rests against a
moving wheel and designed to take a current
from or to transmit it to the wheel.

The Motor Boys Series

(_Trade Mark, Reg. U. S. Pat. Of._)

By CLARENCE YOUNG

12mo. Illustrated. Price per volume, 60 cents, postpaid.

=The Motor Boys=
_or Chums Through Thick and Thin_

=The Motor Boys Overland=
_or A Lone Trip for Fun and Fortune_

=The Motor Boys in Mexico.=
_or The Secret of The Buried City_

=The Motor Boys Across the Plains=
_or The Hermit of Lost Lake_

=The Motor Boys Afloat=
_or The Stirring Cruise of the
Dartaway_

=The Motor Boys on the Atlantic=
_or The Mystery of the Lighthouse_

=The Motor Boys in Strange Waters=
_or Lost in a Floating Forest_

=The Motor Boys on the Pacific=
_or The Young Derelict Hunters_

=The Motor Boys in the Clouds=
_or A Trip for Fame and Fortune_

=The Motor Boys Over the Rockies=
_or A Mystery of the Air_

=The Motor Boys Over the Ocean=
_or A Marvellous Rescue in Mid-Air_

=The Motor Boys on the Wing=
_or Seeking the Airship Treasure_

=The Motor Boys After a Fortune=
_or The Hut on Snake Island_

=The Motor Boys on the Border=
_or Sixty Nuggets of Gold_

=The Motor Boys Under the Sea=
_or From Airship to Submarine_

=The Motor Boys on Road and River=
(_new_) _or Racing to Save a Life_

CUPPLES & LEON CO., Publishers, NEW YORK

Up-to-date Baseball Stories

Baseball Joe Series

By LESTER CHADWICK

Author of "The College Sports Series"

12mo. Illustrated. Price per volume, 60 cents, postpaid.

* * * * *

Ever since the success of Mr. Chadwick's "College Sports Series" we have been urged to get him to write a series dealing exclusively with baseball, a subject in which he is unexcelled by any living American author or coach.

Baseball Joe of the Silver Stars

_or The Rivals of Riverside_

In this volume, the first of the series, Joe is introduced as an everyday country boy who loves to play baseball and is particularly anxious to make his mark as a pitcher. He finds it almost impossible to get on the local nine, but, after a struggle, he succeeds. A splendid picture of the great national game in the smaller towns of our country.

Baseball Joe on the School Nine

_or Pitching for the Blue Banner_

Joe's great ambition was to go to boarding school and play on the school team. He got to boarding school but found it harder making the team there than it was getting on the nine at home. He fought his way along, and at last saw his chance and took it, and made good.

Baseball Joe at Yale

_or Pitching for the College Championship_

From a preparatory school Baseball Joe goes to Yale University. He makes the freshman nine and in his second year becomes a varsity pitcher and pitches in several big games.

Baseball Joe in the Central League

_or Making Good as a Professional Pitcher_

In this volume the scene of action is shifted from Yale College to a baseball league of our central states. Baseball Joe's work in the box for Old Eli had been noted by one of the managers and Joe gets an offer he cannot resist. Joe accepts the offer and makes good.

Baseball Joe in the Big League

_or A Young Pitcher's Hardest Struggle_

From the Central League Joe is drafted into the St. Louis Nationals. At first he has little to do in the pitcher's box, but gradually he wins favor. A corking baseball story that fans, both young and old, will enjoy.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

The Racer Boys Series

by CLARENCE YOUNG

Author of "The Motor Boys Series", "Jack Ranger Series", etc. etc.

Fine cloth binding. Illustrated. Price per volume, 60c postpaid.

* * * * *

The announcement of a new series of stories by Mr. Clarence Young is always hailed with delight by boys and girls throughout the country, and we predict an even greater success for these new books, than that now enjoyed by the "Motor Boys Series."

=The Racer Boys= or The Mystery of the Wreck

This, the first volume of the series, tells who the Racer Boys were and how they chanced to be out on the ocean in a great storm. Adventures follow in rapid succession in a manner that only Mr. Young can describe.

=The Racer Boys At Boarding School= or Striving for the Championship

When the Racer Boys arrived at the school everything was at a standstill, and the students lacked ambition and leadership. The Racers took hold with a will, got their father to aid the head of the school financially, and then reorganized the football team.

=The Racer Boys To The Rescue= or Stirring Days in a Winter Camp

Here is a story filled with the spirit of good times in winter--skating, ice-boating and hunting.

=The Racer Boys on The Prairies= or The Treasure of Golden Peak

From their boarding school the Racer Boys accept an invitation to visit a ranch in the West.

=The Racer Boys on Guard= or The Rebellion of Riverview Hall

Once more the boys are back at boarding school, where they have many frolics, and enter more than one athletic contest.

=The Racer Boys Forging Ahead= or The Rivals of the School League

Once more the Racer Boys go back to Riverview Hall, to meet their many chums as well as several enemies. Athletics play an important part in this volume, and the rivalry is keen from start to finish. The Racer Boys show what they can do under the most trying circumstances.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

The Dorothy Dale Series

By MARGARET PENROSE

Author of "The Motor Girls Series"

12mo. Illustrated. Price per volume, 60 cents, postpaid.

* * * * *

Dorothy Dale: A Girl of To-Day

Dorothy is the daughter of an old Civil War veteran who is running a weekly newspaper in a small Eastern town. When her father falls sick, the girl shows what she can do to support the family.

Dorothy Dale at Glenwood School

More prosperous times have come to the Dale family, and Major Dale resolves to send Dorothy to a boarding school.

Dorothy Dale's Great Secret

A splendid story of one girl's devotion to another. How Dorothy kept the secret makes an absorbing story.

Dorothy Dale and Her Chums

A story of school life, and of strange adventures among the gypsies.

Dorothy Dale's Queer Holidays

Relates the details of a mystery that surrounded Tanglewood Park.

Dorothy Dale's Camping Days

Many things happen, from the time Dorothy and her chums are met coming down the hillside on a treacherous load of hay.

Dorothy Dale's School Rivals

Dorothy and her chum, Tavia, return to Glenwood School. A new student becomes Dorothy's rival and troubles at home add to her difficulties.

Dorothy Dale in the City

Dorothy is invited to New York City by her aunt. This tale presents a clever picture of life in New York as it appears to one who has never before visited the Metropolis.

Dorothy Dale's Promise

Strange indeed was the promise and given under strange circumstances. Only a girl as strong of purpose as was Dorothy Dale would have undertaken the task she set for herself.

Dorothy Dale in the West

Dorothy's father and her aunt inherited a valuable tract of land in the West. The aunt, Dorothy and Tavia, made a long journey to visit the place, where they had many adventures.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

The Motor Girls Series

By MARGARET PENROSE

Author of the highly successful "Dorothy Dale Series"

12mo. Illustrated. Price per volume, 60 cents, postpaid.

* * * * *

The Motor Girls _or A Mystery of the Road_

When Cora Kimball got her touring car she did not imagine so many adventures were in store for her. A tale all wide awake girls will appreciate.

The Motor Girls on a Tour _or Keeping a Strange Promise_

A great many things happen in this volume. A precious heirloom is missing, and how it was traced up is told with absorbing interest.

The Motor Girls at Lookout Beach _or In Quest of the Runaways_

There was a great excitement when the Motor Girls decided to go to Lookout Beach for the summer.

The Motor Girls Through New England _or Held by the Gypsies_

A strong story and one which will make this series more popular than ever. The girls go on a motoring trip through New England.

The Motor Girls on Cedar Lake _or The Hermit of Fern Island_

How Cora and her chums went camping on the lake shore and how they took trips in their motor boat, are told in a way all girls will enjoy.

The Motor Girls on the Coast _or The Waif from the Sea_

The scene is shifted to the sea coast where the girls pay a visit. They have their motor boat with them and go out for many good times.

The Motor Girls on Crystal Bay _or The Secret of the Red Oar_

More jolly times, on the water and at a cute little bungalow on the shore of the bay. A tale that will interest all girls.

The Motor Girls on Waters Blue _or The Strange Cruise of the Tartar_

Before the girls started on a long cruise down to the West Indies, they fell in with a foreign girl and she informed them that her father was being held a political prisoner on one of the islands. A story that is full of fun as well as mystery.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

Ruth Fielding Series

By ALICE B. EMERSON

12mo. Illustrated. Price per volume, 40 cents, postpaid.

* * * * *

Ruth Fielding of The Red Mill _or Jaspar Parloe's Secret_

Telling how Ruth, an orphan girl, came to live with her miserly uncle, and how the girl's sunny disposition melted the old miller's heart.

Ruth Fielding at Briarwood Hall _or Solving the Campus Mystery_

Ruth was sent by her uncle to boarding school. She made many friends, also one enemy, who made much trouble for her.

Ruth Fielding at Snow Camp _or Lost in the Backwoods_

A thrilling tale of adventures in the backwoods in winter, is told in a manner to interest every girl.

Ruth Fielding at Lighthouse Point _or Nita, the Girl Castaway_

From boarding school the scene is shifted to the Atlantic Coast, where Ruth goes for a summer vacation with some chums.

Ruth Fielding at Silver Ranch _or Schoolgirls Among the Cowboys_

A story with a western flavor. How the girls came to the rescue of Bashful Ike, the cowboy, is told in a way that is most absorbing.

Ruth Fielding on Cliff Island _or The Old Hunter's Treasure Box_

Ruth and her friends go to Cliff Island, and there have many good times during the winter season.

Ruth Fielding at Sunrise Farm _or What Became of the Raby Orphans_

Jolly good times at a farmhouse in the country, where Ruth rescues two orphan children who ran away.

Ruth Fielding and the Gypsies _or The Missing Pearl Necklace_

This volume tells of stirring adventures at a Gypsy encampment, of a missing heirloom, and how Ruth has it restored to its owner.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

The Dave Dashaway Series

By ROY ROCKWOOD

Author of the "Speedwell Boys Series" and the "Great Marvel Series."

12mo. Illustrated. Price per volume, 40 cents, postpaid.

* * * * *

Never was there a more clever young aviator than Dave Dashaway. All up-to-date lads will surely wish to read about him.

* * * * *

Dave Dashaway the Young Aviator _or In the Clouds for Fame and Fortune_

This initial volume tells how the hero ran away from his miserly guardian, fell in with a successful airman, and became a young aviator of note.

Dave Dashaway and His Hydroplane _or Daring Adventures Over the Great Lakes_

Showing how Dave continued his career as a birdman and had many adventures over the Great Lakes, and how he foiled the plans of some Canadian smugglers.

Dave Dashaway and His Giant Airship _or A Marvellous Trip Across the Atlantic_

How the giant airship was constructed and how the daring young aviator and his friends made the hazardous journey through the clouds from the new world to the old, is told in a way to hold the reader spellbound.

Dave Dashaway Around the World _or A Young Yankee Aviator Among Many Nations_

An absorbing tale of a great air flight around the world, of adventures in Alaska, Siberia and elsewhere. A true to life picture of what may be accomplished in the near future.

Dave Dashaway: Air Champion _or Wizard Work in the Clouds_

Dave makes several daring trips, and then enters a contest for a big prize. An aviation tale thrilling in the extreme.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

The Speedwell Boys Series

By ROY ROCKWOOD

Author of "The Dave Dashaway Series," "Great Marvel Series," etc.

12mo. Illustrated. Price per volume, 40 cents, postpaid.

* * * * *

All boys who love to be on the go will welcome the Speedwell boys. They are clean cut and loyal lads.

* * * * *

The Speedwell Boys on Motor Cycles _or The Mystery of a Great Conflagration_

The lads were poor, but they did a rich man a great service and he presented them with their motor cycles. What a great fire led to is exceedingly well told.

The Speedwell Boys and Their Racing Auto _or A Run for the Golden Cup_

A tale of automobiling and of intense rivalry on the road. There was an endurance run and the boys entered the contest. On the run they rounded up some men who were wanted by the law.

The Speedwell Boys and Their Power Launch _or To the Rescue of the Castaways_

Here is an unusual story. There was a wreck, and the lads, in their power launch, set out to the rescue. A vivid picture of a great storm adds to the interest of the tale.

The Speedwell Boys in a Submarine _or The Lost Treasure of Rocky Cove_

An old sailor knows of a treasure lost under water because of a cliff falling into the sea. The boys get a chance to go out in a submarine and they make a hunt for the treasure.

The Speedwell Boys and Their Ice Racer _or The Perils of a Great Blizzard_

The boys had an idea for a new sort of iceboat, to be run by combined wind and motor power. How they built the craft, and what fine times they had on board of it, is well related.

* * * * *

CUPPLES & LEON CO., Publishers, NEW YORK

* * * * *