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Project Gutenberg's Wrinkles in Electric Lighting, by Vincent Stephen

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Title: Wrinkles in Electric Lighting

Author: Vincent Stephen

Release Date: January 20, 2011 [EBook #35015]

Language: English

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                                WRINKLES
                                   IN
                           ELECTRIC LIGHTING.




                                WRINKLES
                                   IN
                           ELECTRIC LIGHTING.

                                   BY

                            VINCENT STEPHEN.

                             [Illustration]

                  E. & F. N. SPON, 125, STRAND, LONDON.

                     NEW YORK: 12, CORTLANDT STREET.

                                  1888.




INTRODUCTION.


In the following pages it is my intention to give engineers on board
ship, who may be put in charge of electric lighting machinery without
having any electrical knowledge, some idea of the manner in which
electricity is produced by mechanical means; how it is converted into
light; what precautions must be used to keep the plant in order, and
what to do in the event of difficulties arising. I do not therefore aim
at producing a literary work, but shall try and explain everything in
the plainest language possible.




CONTENTS.


  THE ELECTRIC CURRENT, AND ITS PRODUCTION BY CHEMICAL MEANS.       PAGE

  Production of electric current in chemical battery--Current very
  weak--Current compared to circulation of the blood--Strength and
  volume of current--Pressure not sufficient without volume--Action
  of current is instantaneous--Resistance to the passage of the
  current--Copper the usual metal for conductors--Heat produced by
  current when wire is too small                                       1


  PRODUCTION OF ELECTRIC CURRENTS BY MECHANICAL MEANS.

  _Magneto-Electric Machines._

  Current produced by mechanical means--Alternating current--
  Magneto-electric machines--Shock produced by interruption of
  current--The current must be commutated--Description of
  commutator--Current, though alternating in the dynamo, is
  continuous in the circuit--Continuous current used for
  electro-plating                                                      5

  _Dynamo-Electric Machines._

  Current will magnetise an iron or steel bar--Permanent magnet--
  Electro-magnet--Where the magneto and dynamo machines differ--
  Armature of so-called continuous-current dynamo--Type of
  commutator--Commutator brushes--Current continuous in the
  circuit--Alternating-current dynamos--Current not commutated--
  Intense magnetic field produced--Simplicity of Ferranti armature--
  Large number of alternations of the current--Alternating current
  cannot be used to excite an electro-magnet--Exciter coupled on
  to same spindle as dynamo--Power of exciter if used alone            9


  ELECTRIC LAMPS.

  Production of electric light--Arc lights--Mechanism to regulate
  carbons--Some lamps suitable for alternating current--When
  carbons are consumed, light goes out--Arc lamps very complicated--
  Jablochkoff candles--Arc formed between the carbons--Candles
  require alternating current--Incandescent lamps--Vacuum formed
  in lamps prevents combustion--Vacuum not perfect--Advantages of
  incandescent lamps for house and ship lighting--Unaffected by
  wind, and suitable for either continuous or alternating currents    19


  LEADS.

  Leads made usually of copper wire--Short circuit--High E.M.F. for
  arc lights, but low for incandescent--Arc lights in series--
  Incandescent lamps in parallel circuit--E.M.F. same for one lamp
  as for a number--If lamps suitable, each one turns on and off
  separately--Safety fuses                                            24


  SHIP LIGHTING.

  Position for dynamo--Dynamo to be kept clean and cool--Quick-speed
  engines--Slow-speed engines with belts--Means of keeping belt on
  the pulley--Engine must work steadily--A good sensitive governor
  wanted--The belt must be kept tight--A handy belt-stretcher--
  Friction gearing--Switch board near dynamo--Leads of different
  colours--Main leads and branch leads--Lamps held in frosted
  globes--Switches for each lamp--Lamps of various candle-powers--
  Plan for lighting quarter-deck at times--Arrangement of
  temporary leads--Leads and lamps always ready, and easily fixed
  up--Lighting of ships' holds--Danger of fire with oil lamps--Arc
  lamps not suitable--Arrangement of leads for incandescent lamps--
  Work carried on better, and pilfering of cargo prevented--Hold
  leads disconnected while at sea--Installation complete--Lights
  wanted as night approaches--Precautions before starting dynamo--
  Lubrication must be perfect--Commutators and collectors require
  very little oil--Position of brushes--Start the engine--Switches
  not turned on; no current except from exciter--Testing work
  of exciter--Dynamos very powerful magnets--Look out for your
  watches--Switch on the lamps--Current is produced in large dynamo--
  Difference of a few lamps compensated by governor--Turn all
  lamps on, and light up gradually--Inequality of light in different
  lamps--Weeding out of bad lamps--Lamps not to be run too bright--
  No trouble with dynamo if oiling is attended to--Seizing--Oil
  must be thin--The dynamo must be kept clean--Little troubles with
  the lamps--No safety fuse--Effects of vibration of ship on lamps--
  What to look to if a lamp is out.--Recapitulation--A current of
  50 volts is hardly felt--Incandescent lights for side lights--
  Mast-head light--Arc light should never be used--Present mast-head
  light quite powerful enough--On passenger steamers, side one
  blaze of light, and side lights barely visible--Speed of dynamo
  constant, but steam power used in proportion to number of lamps
  in use--No danger to life from electric current on board ship--
  Binnacle lamps. Electric light not suitable--Dynamo if near a
  compass will affect it--Notes                                       27




WRINKLES IN ELECTRIC LIGHTING.

THE ELECTRIC CURRENT, AND ITS PRODUCTION BY CHEMICAL MEANS.


[Illustration: FIG. 1.]

It will first be necessary to explain how electric currents are produced
by means of chemicals. In a jar A, Fig. 1, are placed two plates B and
C, one zinc, and the other copper, each having connected to it at the
top a copper wire of any convenient length. The plates are kept in
position by means of pieces of wood, and the jar is about half filled
with a solution of salt and water, or sulphuric acid and water; if then
the two wires are joined, a current of electricity at once flows through
them, however long they may be. The current produced in this manner is
very weak, and does not even keep what strength it has for any length of
time, but rapidly gets weaker until quite imperceptible. The current
is, however, continuous; that is, it flows steadily in the one direction
through the wire, and may be used for ringing bells, or for other
purposes where a feeble current only is required to do intermittent
work. The wire E in connection with the copper plate is called the
positive lead, and the other the negative, and the current is said to
flow from the copper plate, through the wire E through the circuit to D,
and thence to the zinc plate, and through the liquid to the copper
plate. The current has often been compared to water flowing through a
pipe, but I think it can be better compared to the blood in the human
body, which through the action of the heart is continually forced
through the arteries and veins in one steady stream. There is, however,
this difference, that there is no actual progression of matter in the
electric current, it being like a ripple on water, which moves from end
to end of a lake without the water itself being moved across. Now that I
have given you an idea of how the current acts, I must try and explain
how different degrees of strength and volume are obtained. In the first
place, let us consider what constitute strength and volume in an
electric current, or at least try and get a general notion about them.
For this purpose I shall compare the electric current to water being
forced through a pipe; and the strength of the electric current, or
electromotive force, written for short E.M.F., will be like the pressure
of water at any part of the pipe. Two pipes may carry different
quantities of water, and yet the pressure may be the same in each; in
one a gallon of water may pass a given point in the same time that a
pint passes the same point in the other, and yet in each case the
different quantities may pass that point at the same speed. Thus in
electricity, two currents may be of different volume or quantity,
measured in amperes, and yet be of the same E.M.F. measured in volts; or
they may be of different E.M.F., or pressure, or intensity, and yet be
of the same volume. If any work is to be done by the water forced
through a pipe, such as turning a turbine, it is evident that pressure
of itself is not sufficient, seeing that a stream an inch in diameter
may be at the same pressure as another a foot in diameter. So with the
electric current, if work is to be done, such as driving a motor or
lighting a lamp, it is not sufficient to have a certain E.M.F.; there
must be quantity or volume in proportion to the amount of work, so that
if it takes a given quantity to work one lamp, it will take twice that
quantity to work two lamps of the same kind. It must not be inferred
from this, that if one lamp requires a certain E.M.F., that two lamps
will require it to be doubled, as such is not the case, except under
certain conditions which I will explain later on.

The action of electricity is practically instantaneous in any length of
wire, so that if the current is used to ring two bells a mile apart,
but connected by wires, they will commence to ring simultaneously. I
have so far not said anything about resistance to the passage of the
current through the wires. I shall therefore refer again to our
comparison of the current to water forced through a pipe, and you will
agree that a certain sized pipe will only convey a certain amount of
water in a given time. If a larger quantity is to be conveyed in the
same time, a greater pressure must be applied, or a larger pipe must be
used.

It is evident that increasing the size of the pipe will get over the
difficulty more readily than increasing the pressure of the water. The
pipes themselves offer a certain resistance to the passage of the water
through them, in the shape of friction; so that if an effect is to be
produced at a distance, rather more pressure is required than if it is
done close at hand, so as to make up for the loss sustained by friction.

Much the same may be said of the electric current; a certain sized wire
will only carry a certain current, and if more current is required, a
thicker wire must be used to convey it, or it must be of a greater
E.M.F. It is usually more convenient to increase the thickness of the
wire than to increase the E.M.F. of the current. The wire offers a
certain resistance to the passage of the current through it, which may
be compared to friction, and this resistance varies according to the
metal of which it is composed. Copper is the metal in ordinary use for
wires for electric lighting purposes, and the purer it is the better
will it convey the current. Iron is used for telegraph wires on account
of cheapness, the current used being so small that this metal conveys it
readily enough; if copper were used, the wires will only require to be
about one-third the diameter of the iron ones. The following are the
respective values for electrical conductivity of various metals when
pure, taking silver as a standard:--Silver 100, copper 99.9, gold 80,
zinc 29, brass 22, iron 16.8, tin 13.1, lead 8.3, mercury 1.6.

If a wire is made to convey a current which is too large for its
electrical capacity, it will get heated, which decreases its
conductivity, with the result that the heat increases until finally the
wire fuses. I shall have more to say about this when speaking of
electric lighting.




PRODUCTION OF ELECTRIC CURRENTS BY MECHANICAL MEANS.


_Magneto-electric Machines._

I have shown how the electric current is produced by the action of
chemical or primary batteries, and how this current will flow through
suitable conductors. I shall now explain how mechanical power may be
converted into electricity. It has been found that if a wire, preferably
of copper, of which the ends are joined together, is moved past a magnet
a current is induced in the wire, flowing in one direction while the
wire is approaching the magnet, and in the opposite direction while it
is receding from it. This is then not a continuous current like we
obtained from the chemical battery, but an alternating one, and you will
see later on how it can be made to produce similar effects. The oftener
the wire passes the magnet the more electricity is generated, so that if
we make a coil of the wire and move a large number of parts of wire past
at one time, the effects on each part are accumulated; and if instead of
having one magnet to pass before, we have several, the effects will be
doubled or trebled, &c., in proportion to the number. If, again, the
coil is moved at an increased speed past the magnets, the effects will
be still further increased.

[Illustration: FIG. 2.]

[Illustration: FIG. 3.]

The knowledge of these facts led to the construction of the various
magneto-electric machines, of which a familiar type is seen in those
small ones used for medical purposes. They contain a large horse-shoe
magnet, close to the end of which two bobbins of copper wire are made to
revolve at a high speed, and all who have used these machines know that
the more quickly they turn the handle the greater shock the person
receives who is being operated upon. The current generated is really
very feeble, the shock being produced by interrupting it at every half
revolution by means of a small spring or other suitable mechanism. If
the current is not so interrupted, it cannot be felt at all, which may
be proved by lifting up the spring on the spindle of the ordinary kind.
The current is an alternating one, and changes its direction throughout
the circuit, however extended it may be, at every half revolution. If it
is required to have a continuous current, use must be made of what is
termed a commutator, and I shall endeavour to explain the manner in
which it acts as simply as possible. Without going into any further
details as to the construction of the bobbins, and their action at any
particular moment, I shall content myself with saying that if the wire
on the two bobbins is continuous, and the ends are connected, the
current will flow one way during half a revolution, and the other way
during the other half. Now, in Fig. 2, on the spindle A on which the
bobbins are fixed, is fitted a split collar formed of two halves B and
C, to which are joined respectively the ends of the wires + and -. This
collar is insulated from the spindle by a suitable insulating material,
that is to say, a material which does not conduct electricity, such as
wood, ivory, &c., and is represented in Fig. 2 by the dark parts D. So
far the circuit is not complete, so that however quickly you turn the
machine no current is produced. If, however, some means is employed for
joining B and C by a conductor, the alternating current is produced as
before. In Fig. 3, I show a section through B A C. On a base E made of
wood, are fixed two metal springs F and G, which are made to press
against B and C respectively; wires are connected at H and K, which,
joined together, complete the circuit. A continuous current is said to
be + or positive where it leaves a battery, and - or negative where it
returns; it will be convenient to use these signs and terms in the
following explanation. At one portion of the revolution the spindle will
be in the position shown in Fig. 3, and the + current is flowing into B,
through F, to the terminal H, thence through the circuit to the terminal
K, through G to C, and so back through the - wire to the bobbins of the
machine. In Fig. 4 the spindle has made a half revolution, bringing B in
contact with G, and C with F. But by this half turn the current is
reversed in the bobbins, and the + current flows into C, through F, to
terminal H as before, and through the circuit to K, through G and B,
back to the bobbins. Thus you see that in the circuit the current will
be always in the same direction, or continuous, although in the bobbins
it is alternating, and may be used for any purpose for which a
continuous current is required, such as electro-plating, &c.

[Illustration: FIG. 4.]

There are various forms of the magneto-electric machines, as well as of
commutators, but the foregoing shows the general principle of them all.


_Dynamo-electric Machines._

It will now be necessary to explain the nature of a dynamo-electric
machine, called, for shortness, a dynamo, and to show in what it
differs from a magneto-electric machine.

I have explained how an electric current is produced by a wire passing
in front of a magnet; now, this magnet may either be of the ordinary
kind, or it may be what is termed an electro-magnet. One of the effects
which electricity can be made to produce is the magnetising of steel
bars to form the ordinary and well-known permanent magnets which are
used in ships' compasses, &c. To produce this effect, part of the wire
in a circuit is made into a spiral as in Fig. 5.

[Illustration: FIG. 5.]

The steel rod to be magnetised is placed within the spiral, and a
continuous current of electricity is then sent through the wire, which
causes the rod to become magnetised with a North pole at one end, and a
South pole at the other. The more current is passed through the circuit,
and the more turns are in the spiral, the more quickly and strongly is
the rod magnetised; and it will retain its magnetism for an indefinite
time if made of suitable steel. There is a point at which the metal is
said to be saturated with magnetism, and the strength it has then
acquired will be that which it will retain afterwards, although while
under the influence of the current that strength may be considerably
exceeded. If instead of a steel rod one of iron is placed in the
spiral, and the current is passed through as before, it will be
magnetised in the same manner; but as soon as the current is stopped,
the rod loses almost all its magnetism, and if the current is then
passed in the opposite direction the rod will be magnetised in the
opposite way. The softer and more homogeneous is the iron, the more
instantaneously will it acquire and lose its magnetism, and the greater
strength of magnetism it is able to acquire. An iron bar, round which
are wound a large number of turns of insulated or covered wire,
constitutes an electro-magnet. The difference then between a
magneto-electric and a dynamo-electric machine is, that in the former
permanent magnets are used, and in the latter electro-magnets take their
place. I do not intend to go into particulars as to the construction of
the various dynamos in present use, as there are many books to be had in
which these machines are fully described. I need merely say that in the
so-called continuous-current dynamos, the whole or part of the current
produced is made to pass through the coils of the electro-magnets, thus
inducing in them the required magnetism. I showed how, in the
magneto-electric machine, the currents are collected by means of a
commutator, and it is evident that in Figs. 2, 3, and 4 there might be
separate wires coming from each bobbin to B and C; and if there were
more than two bobbins, there might still be two wires from each to B
and C. On the other hand the collecting collar might be split into more
sections; in fact there might be as many sections as bobbins. To show
how the current is collected in continuous-current dynamos, I must give
a short explanation of the revolving part or armature of a standard type
of machine.

In Fig. 6 is shown a horse-shoe magnet, with its North and South poles,
N and S. Between these poles is made to revolve the armature, composed
of a number of coils of wire made to form a ring like a life-buoy. The
ends of the wires are made to lie along a collar on the spindle, made of
some insulating material, each wire being parallel to its neighbour, and
kept separate from it, as shown in Fig. 7.

[Illustration: FIG. 6.]

[Illustration: FIG. 7.]

These wires are so arranged that if one end of a sectional coil is on
top of the spindle at a given moment, the other will be on the under
side. If then, as shown in Fig. 7, a rubber of copper, made in the form
of a brush of copper wire for convenience, is placed in contact with the
upper part of the commutator collar, and another similar one with the
lower, it is evident the circuit will be completed in the same manner as
before explained.

[Illustration: FIG. 8. Edison Dynamo.]

A wire which is + when above the spindle, will be - when below it,
and as the spindle revolves the current changes in the various wires
from - to + as they reach the top, so that it will always therefore
be + in the upper brush and - in the lower one, and will accordingly be
continuous through the circuit. It will be seen in the illustrations
of various continuous-current dynamos, that though their shape and
arrangement differ, the mode of collecting the current is much about the
same as I have described above. Figs. 8 and 9 show some of the
continuous-current dynamos at present in use.

[Illustration: FIG. 9. Brush Dynamo.]

I will now explain the nature of an alternating-current dynamo.

The principal difference between the continuous-and alternating-current
dynamo, is in the number of magnets used. Most of the former have only
four magnets, while the latter have frequently as many as thirty-two. In
reality, as I have shown, these are all alternating-current dynamos,
only that in the so-called continuous-current ones, the current is
commutated, whereas in the others it is not, but is used as it is
produced. In the principal alternating-current dynamos, a number of
small magnets, usually sixteen, are attached to a framework directly
opposite a similar number of others of the same size, the space between
the ends being only about an inch or two. These are all electro-magnets,
and are wound in such manner that when excited by a current, every
alternate one shall have the same magnetism, as in Fig. 10, and every
opposite one a contrary magnetism.

This produces an intense magnetic field between the ends of the magnets,
and in this space revolves the armature. This armature, in the Siemens
dynamo, is composed of a disc having as many bobbins on the periphery as
there are magnets on each side of the dynamo. As each bobbin approaches
each magnet a current is induced in one direction, which is reversed
when the bobbin recedes; thus an alternating current is produced, which
is collected by connecting the ends to insulated rings or collars on the
spindle, and having small copper brushes or rubbers in contact with
them. In the Ferranti dynamo, the armature is quite different, and much
more simple, as comparison of Figs. 11 and 12 will show.

[Illustration: FIG. 10.]

[Illustration: FIG. 11. Siemens Armature.]

[Illustration: FIG. 12. Ferranti Armature.]

It consists of a copper tape bent in and out so as to form a sort of
star with eight arms, the number of layers of insulated copper tape
being from ten to thirty, according to requirements. The centre is made
in a similar shape with bolts or rivets holding each convolution in
place. The two ends of the tape are attached respectively to two
collector-rings on the spindle, against which press two solid metal
rubbers which carry off the current for use in the circuit. It can be
shown that as each arm approaches a magnet a current will be induced in
one direction, which will be reversed as each arm recedes; and therefore
an alternating current will be produced. As there are sixteen magnets
for the armature to pass at each revolution, there must be sixteen
alternations of the current during the same time, so that if the speed
of the armature is 500 revolutions per minute, there will be 500 x 16 =
8000 alternations in one minute. These alternations being so extremely
rapid, when this current is used for electric lighting, the steadiness
of the light will be in no way affected, but will remain as constant as
with a continuous current.

[Illustration: FIG. 13. Siemens Alternating Dynamo.]

The alternating current produced by these dynamos cannot be used for
exciting an electro-magnet, as the magnetism would be reversed at every
alternation; a separate small dynamo of the continuous type is therefore
used as an exciter to magnetise all the electro-magnets in the field,
and it is usually coupled on to the same spindle, and therefore goes at
the same speed as the alternating-current dynamo. The exciter is usually
of a size to be able to do alone about one-tenth to one-twentieth of
the work that the larger machines does in the way of lighting; so that
if from any cause the latter is disabled while the ship lighted by it is
at sea, the exciter may be used alone to do a portion of the lighting,
in the first-class saloon for instance. This can only be done if the
exciter is so constructed as to give the proper E.M.F. that the lamps
require.

[Illustration: FIG. 14. Ferranti Alternating Dynamo.]

Figs. 13 and 14 are illustrations of two of the alternating current
dynamos in use on board ship and elsewhere.




ELECTRIC LAMPS.


I have explained how power can be converted into electric currents,
either continuous or alternating, and I must now show how these currents
can be applied to the production of light.

[Illustration: FIG. 15.]

The current may be used to produce an _arc light_ in the following
manner:--Two carbon rods, A and B, are held by suitable means in the
position shown in Fig. 15, and the two wires from a dynamo are joined
respectively to A and B, the upper one always being the positive lead
when a continuous current is used. When the current is sent through the
circuit, it passes through the carbons A and B, which are conductors.
Immediately this occurs, suitable mechanism in the lamp, being acted on
by the current, or by hand in the case of search-lights, or by
clock-work, moves the two carbons a small distance apart, with the
consequence that a dazzling arc of light is formed between them. If the
carbons get too far apart, the mechanism brings them nearer together
again, and on the delicacy with which it acts, depends the steadiness of
the light. It would be useless to explain how this mechanism acts, as it
is in a different form in each maker's lamp. Some lamps have been
constructed for use with an alternating current, but with the majority a
continuous current is used. While an arc light is burning the carbons
waste away, the upper one more rapidly than the lower, and the mechanism
has to approach them constantly to make up for this waste.

When the carbons are consumed as far as convenient, an automatic
arrangement cuts off the current, and the light goes out; or it diverts
the current to another set of carbons, which at once light up. The
carbons are made in suitable lengths to last a certain number of hours,
four, six, eight, &c. In Fig. 16 is shown an arc lamp complete.

[Illustration: FIG. 16. Arc Lamp Complete.]

An arc lamp is of necessity a complicated affair, which it is not
advisable to have on board ship, except where an electrician is engaged
permanently.

Another way of producing light is to use the current in what is called
an _electric candle_, of which a familiar type is the Jablochkoff
candle.

Fig. 17 shows the form of this candle, A and B being two carbon rods
parallel to one another, and joined, but at the same time insulated from
one another by kaolin, a sort of chalky substance, which is a
non-conductor.

[Illustration: FIG. 17.]

The wires C and D from the dynamo are joined respectively to A and B
through metallic supports, as in an arc lamp, and when the current is
turned on it flows through C A and across by a small strip of carbon E
to B and D back to the dynamo. The strip E is only large enough to carry
the current across for a moment, and is immediately consumed, but an arc
of light is then formed between the carbons as in the arc lamp. As the
carbons consume, the kaolin in between burns away, just in the same
manner as, in an ordinary candle, the wick is consumed and the wax melts
and burns away, except that in the latter case the wax feeds the light,
whereas the kaolin is only used to keep the carbons the required
distance apart and the arc of light from running down them. It is
evident that the carbons must be consumed equally, for which reason use
must be made of the alternating current. Any unsteadiness that occurs in
the light produced is consequent on unsteadiness of the current, or
impurities in the carbons, &c., there being no mechanism of any kind
required. These candles do not give such a great light as arc lights,
but it is of the same nature in every way. Fig. 18 shows one of these
candles in its holder, from which can be seen how electrical contact is
made with the two carbons.

[Illustration: FIG. 18.]

If the current is interrupted in any way, and the light goes out, it
will not be produced again automatically, but requires a small piece of
carbon between the two carbons as a path for the current to pass across
as in the beginning.

A third form of electric light is produced by using the current in an
_incandescent lamp_.

To explain the action of an incandescent lamp, I must refer back to what
I said about wires getting heated by a current being passed through them
which was too large for their capacity. If two large wires are joined by
a small one, and a strong current is passed through the circuit, the
small wire rapidly gets red hot, and finally fuses. If this small wire
is contained in a globe from which the air is exhausted, when the
current is passed through it, it gets red, then white hot, and when
very brilliant gets fused. If, instead of wire, we have in the small
globe a thin filament of carbon, when the current is passed through, we
get a brilliant light which remains constant because the carbon does not
fuse, and it cannot burn away for want of air. Fig. 19 shows a Swan
lamp, and Fig. 20 an Edison lamp, both made on this principle.

[Illustration: FIG. 19.]

[Illustration: FIG. 20.]

If in these lamps the vacuum were perfect, the carbon filament would
never get consumed; it is, however, impossible to get a perfect vacuum,
but the better it is, the longer will the filament last. Incandescent
lamps are the only ones that are suitable for house or ship lighting.
[Advantages of incandescent lamps for house and ship lighting.] They
give a yellowish light like a good gas-flame, they do not consume the
air of a room, they cause no smell, and only give out a very slight
heat. They are perfectly safe, because if the globe gets broken and
allows air to get in, the filament is instantly consumed, and the light
goes out. They can be put in all sorts of places where it would be
impossible to have any other lamps, such as near the ceiling, close to
curtains, in a room full of explosives or combustibles, and even under
water. They are not affected by wind; they can therefore be used under
punkahs, or near open windows, sky-lights, or ports, or in the open air.
These lamps can be used with either continuous or alternating currents,
but will probably last longer with the latter, because, when a
continuous current is used, particles of the carbon of the filament
appear to be conveyed from one end of the filament to the other,
reducing the thickness at the one end, until finally it breaks. This
evidently cannot occur with an alternating current, as the impulse in
one direction is counteracted by the following one in the opposite
direction. If the current used is of too high a tension for the lamps,
they will show an intensely brilliant light for a short time, but the
filament will soon be destroyed, and the lamp rendered useless.




LEADS.


We have now to consider the means used for conveying the current,
continuous or alternating, to the lamps we intend to use. The leads for
the electric current, which correspond in some measure with the pipes
which convey gas, are made of copper wire, as pure as can be obtained,
covered with some insulating material to prevent the escape of the
current through contact with other conductors. The size of the wire is
regulated according to the amount of current which is to be conveyed; it
will do no harm to have it of twice the required section, but if it is
of less than the required section, it will offer so much resistance to
the passage of the current, that it will probably get fused in a very
short time. If the lead attached to one terminal of the dynamo comes
back to the other terminal without there being any lamps in the circuit,
or other means of making use of the current, it is said to be short
circuited, and if the dynamo is kept going something must give out very
soon. The two leads must therefore never be connected with one another,
except by a lamp or other resistance, and the manner in which the lamps
are placed, and the size of the leads, depend upon the relative tension
and quantity of current and the kind of lamps to be used. If the current
is to be used in arc lamps it is usual to have a high E.M.F., which
allows of the leads being of small section; but if it is to be used in
incandescent lamps it is found more convenient to have a low E.M.F., and
as this implies a large quantity of current, the leads have to be of
large section.

Arc lamps usually require to be placed in series, that is to say, in
such a manner that the current, after leaving the dynamo, passes through
each lamp in succession. The E.M.F. required in this case is the sum of
the E.M.F. for each lamp, the quantity required being the same as for
one lamp. This accounts for the high E.M.F. used in arc lighting and
the small size of the wire for conducting the current. Incandescent
lamps can be either in series or parallel, and frequently the two
systems are combined. To explain the meaning of having lamps parallel,
we will suppose the two leads from a dynamo to be taken along a wall,
parallel to one another, and about six inches apart, ending at the end
of the wall, but not connected in any way. If we then place lamps at
intervals between the two leads, connecting one loop of each to the
upper lead, and the other to the lower lead, by means of small copper
wire, these lamps are said to be all parallel. In this arrangement the
current required is the sum of the quantity necessary for each lamp, but
the E.M.F. is the same as that required for one lamp of the same kind.
As we therefore require to send a large quantity of current through the
leads at a small pressure or E.M.F., these leads must be of large
section. In the above arrangement each lamp may be turned on or off
separately without affecting the others. Sometimes two or more lamps are
placed in groups between the parallel leads; these are then in series
with regard to one another, and can only be turned on or off two or more
at a time, in other words, one group at a time. If our dynamo is
producing a current of 100 volts E.M.F. when working at its proper
speed, and our lamps are 100-volt lamps, we shall be able to turn each
lamp on or off separately; but if we want to put in 50-volt lamps, we
must place two together, and we shall then have to turn them on or off
two at a time. I am supposing that in both cases the lamps require the
same quantity of current, though of different E.M.F.

To prevent the lamps being spoilt by the current being too strong
through a sudden increase in the speed of the dynamo, as also to prevent
the leads getting fused, and perhaps setting fire to the casing, it is
usual to have safety fuses in various parts of the circuit. These are of
different kinds, but a typical one consists of a small lead wire, large
enough to carry the normal current, but which fuses when the current is
too strong, and at once interrupts its passage. The lamps in the same
portion of the circuit are then extinguished and so saved from
destruction, and cannot then be lighted again until the fuse is renewed,
which, however, can be done with ease.




SHIP LIGHTING.


We will consider now the case of a steamship to be lighted by means of
incandescent lamps. It is sometimes a matter of some difficulty to fix
on a suitable position for the dynamo and engine, especially in ships
which have already been running for some time. In selecting a position,
it must be borne in mind that a dynamo will work best in a cool clean
place, cleanliness being most important. If a lot of coal dust is flying
about where the dynamo is working, it will be drawn into it, and tend to
impair its electrical, as well as mechanical efficiency. If the dynamo
is kept properly lubricated, it will work well enough in a hot place,
but we must remember that the heating of the wire which makes up a large
portion of the dynamo, reduces its conductivity, so that the cooler it
is kept the better. The dynamo should be so placed that the engineer can
get to every side of it easily. If a quick-speed engine is to be used
for driving it direct, it will make a very compact installation, but
there seems to be some difficulty as yet in getting suitable reliable
engines, besides which many marine engineers object to quick-speed
engines altogether. If a slow-speed engine is to be used, a belt is of
course required to get the necessary speed on the dynamo, and various
precautions are needful to prevent the belt slipping off the pulley when
the ship is rolling about in a sea-way. In all cases, the engine and
dynamo should be placed with their spindles fore-and-aft, or in a line
with the ship's keel, the rolling being felt more than the pitching.
There are various ways of keeping the belt from slipping off the pulley.
Some have flanges on the pulley, others have guides or rollers on each
side of the belt, each plan having its advantages and disadvantages; but
some plan must be used, otherwise the belt slips off, usually in the
middle of the first-saloon dinner, and out go all the lights, besides
which the belt may be considerably damaged before the engine can be
stopped. The engine must be one that will work very steadily, otherwise
the lights will pulsate at each revolution of the engine, which is most
unpleasant. If the engine is a single one, it must have a large
fly-wheel, or a driving-wheel large and heavy enough to answer the same
purpose. The engine requires a good sensitive governor, so as to keep
the speed regular when some of the lamps are turned on or off. When the
engine and dynamo are in the main engine-room, the throttle-valve, or a
stop-valve, should be in a convenient place for the engineer on watch to
get at so as to instantly shut off the steam if the belt slips off or
breaks. In ships where an electrician is carried there will not be the
same necessity for this precaution. It is necessary to have some means
of tightening up the belt, so as to keep it from slipping round the
pulley. Where the engine and dynamo are on the same level there may be a
screw arrangement in the base-plate of the latter by which the distance
between centres can be increased. Where the engine and dynamo are on
different levels, and the latter is a fixture, recourse must be had to a
roller, bearing against the upper part of the belt and capable of screw
adjustment. If link leather belting is used, it will be found necessary
to take out several rows of links each day until it has finished
stretching. A very handy thing to use for this purpose, and which can be
made on board by an engineer, is a double clamp with a screw in between,
just like the ones which are being sold for stretching trousers which
have got baggy at the knees. Whatever belt is used, it is very important
that there should be no joint or inequality which can cause a jump or
slip when going over the pulley, as this will cause the lights to
pulsate each time. In America friction gearing has been tried, but I do
not know with what success. From my experience of friction gearing, I am
inclined to think it might do very well. There is certainly no doubt
that direct-acting quick-speed engines are the ones to use, and it is
only a question of getting a suitable one.

The dynamo being firmly fixed in position, the main leads are connected
to it, and carried along to the switch-board, which should be in a
convenient position near at hand. On this switch-board are usually
placed the large safety fuses. The board should have a cover to it, to
prevent any one meddling with it, and to keep it clean. The main leads
are of a large size, and from these other smaller ones branch off, being
spliced and soldered to them. It is a very good practice to use leads of
two different colours, as we can then work by the following rule: Never
connect together two leads of different colours except by means of a
lamp or other resistance. The size of the various leads depends on the
current to be conveyed, and is a matter for the electricians. On the
main-deck of a large passenger steamer, the main leads may be carried
along side by side under the upper deck, and from these, smaller ones
branch off into the various sets of rooms, smaller ones still going into
each room. In each room there will be one lamp with its switch to turn
it on or off as desired, and a safety fuse. The lamps are held in small
brackets, and are contained when desired in frosted globes, which
diffuse the light and make it very pleasant. When these globes are held
rigidly in the brackets, the least knock breaks them. A very good
bracket I have seen in use is one which allows the globe to move about
on its support when touched, being at the same time sufficiently a
fixture to resist the motion of the ship; and in the particular ship in
which I saw these used in the first saloon, there was not a single
breakage during a four months' voyage. The switches for turning each
light on or off can be under the control of the passengers, or, on the
other hand, they can be fitted to work with keys kept by the stewards,
as thought most desirable.

The lamps used can be of various candle-powers, within certain limits,
and of whatever make is considered best. They can also be of various
makes, as long as they are constructed to stand the same E.M.F. The
lamps in the passenger berths give quite sufficient light if of
10-candle power; the ones for lighting the saloons, passages, and other
large spaces, may with advantage be of 20-candle power. In these days of
luxurious travelling, when the various lines are trying to attract
passengers to their particular ships, what follows may be thought worth
consideration. In steamers going through the tropics to India, China,
Australia, &c., it is usual to get up dances, concerts, and other
entertainments on the quarter-deck, at times when it would be impossible
to do anything below on account of the heat. The quarter-deck then has
to be lighted up. This is effected by means of globe oil-lamps hung
about here and there, two being hung in front of the piano, in
unpleasant proximity to the head of the obliging lady pianist. Now in a
ship lighted by electricity, there is no reason why a couple of leads
should not be brought up from below through a skylight or other opening,
on to the quarter-deck. Indeed the leads might be arranged to screw into
a place in the deck, or on the side of a skylight, just in the same
manner as a hose is connected for washing decks. These leads would have
holders for lamps fitted permanently at intervals, and when required for
use would be stopped up along the awning-spar or ridge-chains, and the
lamps screwed or hooked into the holders. With a few handy men, five or
ten minutes would suffice to arrange the whole thing after the leads had
once been fitted. The leads once fitted for this purpose would be
always ready for use, and could be kept coiled away in a box which might
also have a compartment to contain the dozen or so of lamps required.

If the dynamo is already running as many lamps as it is capable of, some
of the bedroom lights may be turned off while the quarter-deck is being
lighted. Another thing which I think has not yet been done is the
following. When working cargo at night, and indeed during the day to
some extent, lights are of necessity used in the holds. The _theory_ is,
that no naked lights shall be allowed, but the _practice_ is this: lamps
are taken below, get knocked about, the wicks fall down and want
pricking up, the lamps are opened for this purpose, and as they are
found to give more light without a dusty glass round them than with it,
they are left open. Candles are often taken below lighted, and even
matches struck to see the mark on a bale. I am aware that arc lamps are
used in the Royal Albert Docks, London, in connection with the dock
lighting, lamps being carried below when required, with flexible leads
attached, and that, in some few steamers, arc lamps have been used in
the same manner in connection with their own plant. These arc lamps are,
I think, not nearly as suitable as incandescent lamps for the purpose of
lighting up a ship's hold; the light is too glaring, and casts deep
shadows amongst the bales and cases, besides which, the lamps are large
and clumsy. I would suggest that leads should be carried behind the
stringer-battens in the ship's side, or along under the next upper-deck,
having simple sockets or holders for incandescent lamps at certain
intervals. Whoever might be in charge of the hold would screw or hook on
the lamps as required, and so light up every part of the hold thoroughly
while work was going on. There would be no risk of fire, and I am
convinced that the extra leads and lamps would pay for themselves in a
very short time, because work would get on more quickly, and pilfering
of the cargo would be in a great measure put a stop to. The leads for
the holds could be so arranged as to be quite unconnected with the
dynamo while at sea, so that there could not be the remotest possibility
of the current finding its way below when not wanted. In fine, there is
no reason whatever why a ship's hold should not be lighted up when
required, as well as a warehouse or store on shore.

Now, we will suppose that our installation is complete, ready for
working, everything having been pronounced in order by the electrician
who has looked after the work. Evening is approaching, and the lights
will soon be required; we must therefore see that our engine and dynamo
are ready for a start. If the engine and dynamo are separate, the belt
must be felt, to see that it is tight enough, otherwise it must be
tightened by whatever means are provided for the purpose. We must also
see that the engine and dynamo are properly oiled, and that the
worsteds are down the tubes of the oil-cups, and working properly, not
dry, as I have known them to be, with fatal results to the dynamo. If
the lubrication is performed by means of tubes leading to each bearing
from an elevated oil-box, we must see that the oil really gets to the
bearings, and regulate its flow as required. The commutators and
collector-rings and rubbers require only a wipe of oil, just sufficient
to prevent undue wearing of the surfaces; if too much is put on them,
they will spark a great deal, and sparking will wear them away more
quickly than friction. The brushes of copper wire which collect the
current of the exciter dynamo, and others of similar pattern, must be
placed so that the ends press on the commutator as shown in Fig. 21.
The ends should project just a little way beyond the point or
line of contact, and when the dynamo is running, there should be
very little sparking. I am supposing that our plant consists of an
alternating-current dynamo with a small exciter. The wires leading from
the exciter to the other dynamo remain always connected, as there is no
need for meddling with them.

[Illustration: FIG. 21.]

[Illustration: FIG. 22.]

We will now start the engine, and thereby set the dynamo going round,
slowly at first, and gradually up to the speed required. The main
switches are not yet turned on, so there is no current going through the
leads as yet; what then is being done? A current is being produced by
the exciter only, and is magnetising the electro-magnets of the larger
dynamo, and if we want to know if it is really doing its work as
intended, we just hold a small pocket-compass over the ends of two
opposite magnets of the dynamo, and observe how the needle points. It
should at once take up the position shown in Fig. 22, and if then held
over the next couple in like manner, the needle should simply turn
round, and point in exactly the opposite direction. If it points in any
other direction, there is something wrong with the connections. If,
however, the connections are right at starting, they will of course
remain right, and there should be no need for this test. It is well to
remember that when dynamos are working, they are, or contain for the
time being, very powerful magnets, therefore if we bend over them to
examine them, our watches will get magnetised, which does not improve
their qualities as time-keepers. Say that our dynamo is now going round
at the required speed, which may be 500 or 600 revolutions per minute;
the engine is not using much steam as yet, because very little work is
being done. We now switch on a set of lamps; this closes the circuit,
and the large dynamo begins to produce its alternating current, which
goes through the lamps and lights them up. This, however, gives the
engine more work to do, and more steam must be turned on, otherwise the
necessary speed will not be kept up. We switch on all the other lamps as
required, and must see that the speed of the dynamo is kept constant. A
difference of a few lamps, affecting the engine to a small extent only,
should be compensated automatically by the governor. If the brightest
lamps are not bright enough, the speed should be increased a little, but
care must be taken not to overdo it, because if the current is too
strong, some of the safety fuses will melt, and the corresponding lamps
will go out. It must not be inferred from what I have said, that it is
necessary to run the dynamo at first without switching on any lamps. On
the contrary, a better effect will be produced if all the lamps are
switched on before starting, as they will then gradually work up to
their full brilliancy; whereas, if one set of lamps is started first,
and run bright, and we then switch on another set, the current at first
will be too small for the two sets, and the first set will get quite
dull, remaining so until the dynamo is going at its proper speed again.
When lighted up for the first time, it will be found that some of the
lamps are much brighter than others; this is because the lamps at
present made are not of perfectly equal resistances. We must go round,
then, and note where the dull ones are, and we can either at once, or
during next day, shift them into the bathrooms and places where such a
perfect light is not required. All the lamps in one room, the first
saloon, or music room, for instance, should be equalised as much as
possible, and in such places the brightest should be used. Nothing looks
worse than to see a couple of dull lights in the same room as a lot of
bright ones. By seeing to these matters we can make the lighting much
more satisfactory than it otherwise would be. During the first few
evenings we shall probably have some of the lamps go out through the
filaments breaking. This I consider a weeding out of defective lamps,
because if it were that the current was too strong, the fuses would have
given way. Some of the fuses give way when the current is _not_ too
strong; this is owing to imperfections in the fuses, and they must be
replaced by spare ones. For the sake of economy, it is well not to run
the lamps too bright. Without giving the lamps the maximum current a
very good light can be obtained, and they will last all the longer. I
need hardly say that there is a medium in this as in everything else,
and it does not look well when a candle is placed alongside of an
electric lamp to enable a person to read or write in comfort.

All this time the dynamo is running, and we must feel the bearings
occasionally to see if they are keeping cool. There will be no trouble
if the lubrication is all right. If the oil does not get into the
bearings as it should do, they will heat, jam the spindle, or seize, and
bring up the engine or break the belt. The lights will then all go out,
and everybody will say hard things of the electric light, while the
fault really rests with us. Sometimes seizing occurs through the spindle
not being slack enough in the bearings, but this generally occurs while
testing the dynamo at the works.

It must be borne in mind that in dynamos the spindle must be a good fit,
and there may be room in the bearings for ordinary engine-oil while
there may not be for a thicker oil, such as castor oil. Therefore, if
the bearings show a tendency to heat, it may improve matters to thin the
oil used with petroleum. While giving the dynamo its proper supply of
oil, we must only apply it in the proper places. If we let the bobbins
get smothered in oil, the insulating material on the wire will get
rotted, and a short circuiting will probably take place. The dynamo
cannot be kept too clean, and there should be a canvas cover to put over
it while not in use, especially while coaling. We will suppose that all
is going on right; a steward comes along and says: "Mr. So-and-so, I
cannot get the lamp in number 6 berth to light although I have turned
the switch the right way." "All right, I will go and look at it," you
answer. Now, let us see what is the matter. We unhook or unscrew the
lamp, and look at the filament; it is not broken. We replace the lamp
again, and are careful that it makes good contact; but still no light.
Let us look at the safety fuse; why, there is none! it has been missed
out. We get one of the spare ones out of our electric store, and put it
in its place, and the lamp lights properly at once. We find another lamp
out, and look at it. We see at once that the filament is broken, so
there is no question about this one; it must be changed. Hallo! what is
up with this one? it goes in and out all the time like a flash light.
The current must be getting to it all right, otherwise it would not
light at all. I see what it is; it is a Swan lamp, and the spring is not
pressing quite fairly on it, so that one hook is making good contact,
while the other tightens and slacks with the vibration of the ship. This
is soon set right by turning the spring round a little, or hooking the
lamp the other way. Or it is an Edison lamp, which has got slightly
unscrewed, and no longer makes good contact at the back end of the
holder. In some lamp-fittings the ends of the leads are held in a spring
grip in the base of the bracket, and it may happen that they have
slipped out, and so broken the circuit, and extinguished the light. In
the Swan lamps, and others of a similar pattern, one of the little
platinum loops in the base of the lamps sometimes gets broken off; the
lamp is then of no further use. To recapitulate, if a lamp goes out, the
first thing is to see if the filament is broken, next if it makes good
contact. If it does not then light up, see if there is any current
getting to it; this may be found out by touching the two hooks in a Swan
holder, or the back and side of an Edison screw holder, with a moistened
finger. With a current of 50 volts a slight tickling sensation will be
felt if the current is passing through. If this cannot be felt, there
must be some part or other disconnected, perhaps the safety fuse has
given out, or the ends of the leads got adrift from the bracket. If in
any doubt about the lamp, try another in the same place.

In some steamers incandescent lamps are used in the side lamps; they can
easily be fitted for this purpose, especially when the ship is provided
with lighthouses built in, as in the Anchor Line steamers. Two or more
incandescent lamps can be arranged on a small stand, which will slide
into the lantern, taking the place of the regulation oil lamp, and
connected by flexible leads to the other leads. It would be easy to put
six 20-candle power lamps in a group in each lantern, as it does not
matter in what position they are placed; two might be used on ordinary
occasions, while on a foggy night, the whole six could be switched on.
If one lamp went out through the filament giving way, it would not
affect the others, so that there would still be a light in the lantern.
If, through some breakdown of the engine or dynamo, the electric current
were no longer to be had, then it would only be necessary to withdraw
the stand of lamps, and put in the ordinary regulation oil-lamp. The
mast-head lamp could also be fitted with the electric light, as indeed
has already been done. On no account, however, should an arc light be
used, as besides being too dazzling, it is much too uncertain; in fact
many other reasons could be given for rejecting it. It is even a
question whether it is an advantage to have incandescent lamps for a
mast-head light. There is certainly the great advantage of not having to
pull the lamp up and down to trim it, a rather risky performance in
heavy weather, and also of the light not being affected by any wind that
may get into the lamp; though as regards the first, English officers
would never be satisfied to see a lamp dangling on the stay all day
long, as appears to be the custom in some foreign steamers, besides
which it would have to be lowered to be cleaned outside.

The present mast-head lights are quite powerful enough already, too much
so when compared with the side lights. I am not aware of any collisions
having occurred through a mast-head light not being seen in time, but
how many from the side lights not being seen! It was no doubt
contemplated, as indeed the regulations show, that no lights should be
visible about a vessel, except the regulation lights; but many who have
seen a large passenger steamer go past will have noticed how her side
was--one, two, or three rows of dazzling bright lights, and will have
looked almost in vain for the green or red light dimly visible in the
midst of all the bright ones. If bright electric lights, therefore, are
shining through the ports, we must have our side lights at least as
bright, so as to give them a chance of being seen. If electric lamps are
used as side lights, the dynamo must be kept running all night. If it is
thought desirable to put out all unnecessary lights at 11 P.M., the
leads can be so arranged that these lights can be all on one or more
circuits, and the necessary ones on another.

Although the dynamo will have to go at nearly the same speed throughout
the night, it will not have the same amount of work to do, and the
engine will therefore use much less steam, the consumption being in
proportion to the number of lights used. An economical engineer will
therefore see that bedroom lamps are not kept lighted all the evening
without any necessity. On shore we should never think of keeping
gas-lights blazing away for no purpose, and why should we use
electricity with more lavishness, especially when it is so easy to turn
a light on or off. The switches might with advantage be painted with
Balmain's luminous paint, and there would then be no trouble in finding
them in the dark. It is well to know that on board ship, probably in all
cases of electric lighting, there is no danger to life to be apprehended
from touching any of the leads where bare, or indeed any part of the
dynamos, as the E.M.F. is usually not more than 50 volts. It is best,
however, not to try any experiments, and it is a good general rule, not
to touch a bare part of a dynamo or lead with both hands at the same
time. The fear of getting hurt has the good effect of keeping passengers
and others from meddling with their lamps.

I have said nothing about the use of electric lights in binnacles,
though it would be a great advantage to be able to supply them with a
good steady light quite unaffected by wind. There is an obstacle to
their use for this purpose, in that the electric current being used near
the compass, the latter is affected by it. In theory, an alternating
current should have no effect; but it would require very exhaustive
experiments to be made before enough confidence could be inspired
concerning its innocence, and I fancy it would usually be looked upon
with great suspicion by captains and officers of ships. The dynamo being
made up of powerful magnets, must of course be always at a good distance
from the compasses. In some installations on iron steamers, the return
leads have been dispensed with, the iron of the ship carrying the
current back, in the same way that the earth or sea does it in a
telegraph circuit.

It is to be observed that a dynamo with _brushes_ on the commutator is
not necessarily a _Brush_ dynamo as a good many people seem to think,
the latter being named after its inventor, Mr. Brush.

A dynamo is not a _battery_ as some people call it, and there is no need
for multiplying names.

A pocket speed-indicator should be supplied for testing the speed of the
dynamo, to see that it is kept up to proper speed, and that the belt (if
used) does not slip to an unreasonable extent.

I think I have now said enough to redeem my introductory promise, and if
I have, so to speak, let more electric light on to a subject previously
dark to a good many people, I shall be well satisfied with my labour,
and I hope that those who peruse this book will be induced to go more
deeply into the subject by means of the many good books which have been
written by cleverer men than I, and which enter more thoroughly into all
its details.

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_A Pocket-Book for Chemists, Chemical Manufacturers, Metallurgists,
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etc., etc._ By THOMAS BAYLEY, Assoc. R.C. Sc. Ireland, Analytical and
Consulting Chemist and Assayer. Fourth edition, with additions, 437 pp.,
royal 32mo, roan, gilt edges, 5_s._

     SYNOPSIS OF CONTENTS:

     Atomic Weights and Factors--Useful Data--Chemical Calculations--
     Rules for Indirect Analysis--Weights and Measures--Thermometers and
     Barometers--Chemical Physics--Boiling Points, etc.--Solubility of
     Substances--Methods of Obtaining Specific Gravity--Conversion of
     Hydrometers--Strength of Solutions by Specific Gravity--Analysis--
     Gas Analysis--Water Analysis--Qualitative Analysis and Reactions--
     Volumetric Analysis--Manipulation--Mineralogy--Assaying--Alcohol--
     Beer--Sugar--Miscellaneous Technological matter relating to Potash,
     Soda, Sulphuric Acid, Chlorine, Tar Products, Petroleum, Milk,
     Tallow, Photography, Prices, Wages, Appendix, etc., etc.


_The Mechanician_: A Treatise on the Construction and Manipulation of
Tools, for the use and instruction of Young Engineers and Scientific
Amateurs, comprising the Arts of Blacksmithing and Forging; the
Construction and Manufacture of Hand Tools, and the various Methods of
Using and Grinding them; the Construction of Machine Tools, and how to
work them; Machine Fitting and Erection; description of Hand and Machine
Processes; Turning and Screw Cutting; principles of Constructing and
details of Making and Erecting Steam Engines, and the various details of
setting out work, etc., etc. By CAMERON KNIGHT, Engineer. _Containing
1147 illustrations_, and 397 pages of letter-press, Fourth edition, 4to,
cloth, 18_s._




_Just Published, in Demy 8vo, cloth, containing 975 pages and 250
Illustrations, price 7s. 6d._


SPONS' HOUSEHOLD MANUAL:

     A Treasury of Domestic Receipts and Guide for Home Management.

     PRINCIPAL CONTENTS.

     =Hints for selecting a good House=, pointing out the essential
     requirements for a good house as to the Site, Soil, Trees, Aspect,
     Construction, and General Arrangement; with instructions for
     Reducing Echoes, Waterproofing Damp Walls, Curing Damp Cellars.

     =Sanitation.=--What should constitute a good Sanitary Arrangement;
     Examples (with illustrations) of Well--and Ill-drained Houses; How
     to Test Drains; Ventilating Pipes, etc.

     =Water Supply.=--Care of Cisterns; Sources of Supply; Pipes; Pumps;
     Purification and Filtration of Water.

     =Ventilation and Warming.=--Methods of Ventilating without causing
     cold draughts, by various means; Principles of Warming; Health
     Questions; Combustion; Open Grates; Open Stoves; Fuel Economisers;
     Varieties of Grates; Close-Fire Stoves; Hot-air Furnaces; Gas
     Heating; Oil Stoves; Steam Heating; Chemical Heaters; Management
     of Flues; and Cure of Smoky Chimneys.

     =Lighting.=--The best methods of Lighting; Candles, Oil Lamps, Gas,
     Incandescent Gas, Electric Light; How to test Gas Pipes; Management
     of Gas.

     =Furniture and Decoration.=--Hints on the Selection of Furniture;
     on the most approved methods of Modern Decoration; on the best
     methods of arranging Bells and Calls; How to Construct an Electric
     Bell.

     =Thieves and Fire.=--Precautions against Thieves and Fire; Methods
     of Detection; Domestic Fire Escapes; Fireproofing Clothes, etc.

     =The Larder.=--Keeping Food fresh for a limited time; Storing Food
     without change, such as Fruits, Vegetables, Eggs, Honey, etc.

     =Curing Foods for lengthened Preservation=, as Smoking, Salting,
     Canning, Potting, Pickling, Bottling Fruits, etc.; Jams, Jellies,
     Marmalade, etc.

     =The Dairy.=--The Building and Fitting of Dairies in the most
     approved modern style; Butter-making; Cheesemaking and Curing.

     =The Cellar.=--Building and Fitting; Cleaning Casks and Bottles;
     Corks and Corking; Aerated Drinks; Syrups for Drinks; Beers;
     Bitters; Cordials and Liqueurs; Wines; Miscellaneous Drinks.

     =The Pantry.=--Bread-making; Ovens and Pyrometers; Yeast; German
     Yeast; Biscuits; Cakes; Fancy Breads; Buns.

     =The Kitchen.=--On Fitting Kitchens; a description of the best
     Cooking Ranges, close and open; the Management and Care of Hot
     Plates, Baking Ovens, Dampers, Flues, and Chimneys; Cooking by Gas;
     Cooking by Oil; the Arts of Roasting, Grilling, Boiling, Stewing,
     Braising, Frying.

     =Receipts for Dishes.=--Soups, Fish, Meat, Game, Poultry,
     Vegetables, Salads, Puddings, Pastry, Confectionery, Ices, etc.,
     etc.; Foreign Dishes.

     =The Housewife's Room.=--Testing Air, Water, and Foods; Cleaning
     and Renovating; Destroying Vermin.

     =Housekeeping, Marketing.=

     =The Dining-Room.=--Dietetics; Laying and Waiting at Table;
     Carving; Dinners, Breakfasts, Luncheons, Teas, Suppers, etc.

     =The Drawing-Room.=--Etiquette; Dancing; Amateur Theatricals;
     Tricks and Illusions; Games (indoor).

     =The Bedroom= and Dressing-Room; Sleep; the Toilet; Dress; Buying
     Clothes; Outfits; Fancy Dress.

     =The Nursery.=--The Room; Clothing; Washing; Exercise; Sleep;
     Feeding; Teething; Illness; Home Training.

     =The Sick-Room.=--The Room; the Nurse; the Bed; Sick Room
     Accessories; Feeding Patients; Invalid Dishes and Drinks;
     Administering Physic; Domestic Remedies; Accidents and Emergencies;
     Bandaging; Burns; Carrying Injured Persons; Wounds; Drowning; Fits;
     Frost-bites; Poisons and Antidotes; Sunstroke; Common Complaints;
     Disinfection, etc.

     =The Bath-Room.=--Bathing in General; Management of Hot-Water
     System.

     =The Laundry.=--Small Domestic Washing Machines, and methods of
     getting up linen; Fitting up and Working a Steam Laundry.

     =The School-Room.=--The Room and its Fittings; Teaching, etc.

     =The Playground.=--Air and Exercise; Training; Outdoor Games and
     Sports.

     =The Workroom.=--Darning, Patching, and Mending Garments.

     =The Library.=-Care of Books.

     =The Garden.=--Calendar of Operations for Lawn, Flower Garden, and
     Kitchen Garden.

     =The Farmyard.=--Management of the Horse, Cow, Pig, Poultry, Bees,
     etc., etc.

     =Small Motors.=--A description of the various small Engines useful
     for domestic purposes, from 1 man to 1 horse power, worked by
     various methods, such as Electric Engines, Gas Engines, Petroleum
     Engines, Steam Engines, Condensing Engines, Water Power, Wind
     Power, and the various methods of working and managing them.

     =Household Law.=--The Law relating to Landlords and Tenants,
     Lodgers, Servants, Parochial Authorities, Juries, Insurance,
     Nuisance, etc.


_On Designing Belt Gearing._ By E. J. COWLING WELCH, Mem. Inst. Mech.
Engineers, Author of 'Designing Valve Gearing.' Fcap. 8vo, sewed, 6_d._


_A Handbook of Formulae, Tables, and Memoranda, for Architectural
Surveyors and others engaged in Building._ By J. T. HURST, C. E.
Fourteenth edition, royal 32mo, roan, 5_s._

     "It is no disparagement to the many excellent publications we refer
     to, to say that in our opinion this little pocket-book of Hurst's
     is the very best of them all, without any exception. It would be
     useless to attempt a recapitulation of the contents, for it appears
     to contain almost _everything_ that anyone connected with building
     could require, and, best of all, made up in a compact form for
     carrying in the pocket, measuring only 5 in. by 3 in., and about
     1/4 in. thick, in a limp cover. We congratulate the author on the
     success of his laborious and practically compiled little book,
     which has received unqualified and deserved praise from every
     professional person to whom we have shown it."--_The Dublin
     Builder._


_Tabulated Weights of Angle, Tee, Bulb, Round, Square, and Flat Iron and
Steel_, and other information for the use of Naval Architects and
Shipbuilders. By C. H. JORDAN, M.I.N.A. Fourth edition, 32mo, cloth,
2_s._ 6_d._


_A Complete Set of Contract Documents for a Country Lodge_, comprising
Drawings, Specifications, Dimensions (for quantities), Abstracts, Bill
of Quantities, Form of Tender and Contract, with Notes by J. LEANING,
printed in facsimile of the original documents, on single sheets fcap.,
in paper case, 10_s._


_A Practical Treatise on Heat, as applied to the Useful Arts_; for the
Use of Engineers, Architects, &c. By THOMAS BOX. _With 14 plates._ Third
edition, crown 8vo, cloth, 12_s._ 6_d._


_A Descriptive Treatise on Mathematical Drawing Instruments_: their
construction, uses, qualities, selection, preservation, and suggestions
for improvements, with hints upon Drawing and Colouring. By W. F.
STANLEY, M.R.I. Fifth edition, _with numerous illustrations_, crown 8vo,
cloth, 5_s._


_Quantity Surveying_, By J. LEANING. With 42 illustrations. Second
edition, revised, crown 8vo, cloth, 9_s._

     CONTENTS:

     A complete Explanation of the London Practice.
     General Instructions.
     Order of Taking Off.
     Modes of Measurement of the various Trades.
     Use and Waste.
     Ventilation and Warming.
     Credits, with various Examples of Treatment.
     Abbreviations.
     Squaring the Dimensions.
     Abstracting, with Examples in illustration of each Trade.
     Billing.
     Examples of Preambles to each Trade.
     Form for a Bill of Quantities.
        Do.     Bill of Credits.
        Do.     Bill for Alternative Estimate.
     Restorations and Repairs, and Form of Bill.
     Variations before Acceptance of Tender.
     Errors in a Builder's Estimate.
     Schedule of Prices.
     Form of Schedule of Prices.
     Analysis of Schedule of Prices.
     Adjustment of Accounts.
     Form of a Bill of Variations.
     Remarks on Specifications.
     Prices and Valuation of Work, with Examples and Remarks upon each
       Trade.
     The Law as it affects Quantity Surveyors, with Law Reports.
     Taking Off after the Old Method.
     Northern Practice.
     The General Statement of the Methods recommended by the Manchester
       Society of Architects for taking Quantities.
     Examples of Collections.
     Examples of "Taking Off" in each Trade.
     Remarks on the Past and Present Methods of Estimating.


_Spons' Architects' and Builders' Pocket-Book of Prices and Memoranda._
Edited by W. YOUNG, Architect. Crown 8vo, cloth, _Published annually_.
Fifteenth edition. _Now ready._


_Long-Span Railway Bridges_, comprising Investigations of the
Comparative Theoretical and Practical Advantages of the various adopted
or proposed Type Systems of Construction, with numerous Formulae and
Tables giving the weight of Iron or Steel required in Bridges from 300
feet to the limiting Spans; to which are added similar Investigations
and Tables relating to Short-span Railway Bridges. Second and revised
edition. By B. BAKER, Assoc. Inst. C.E. _Plates_, crown 8vo, cloth,
5_s._


_Elementary Theory and Calculation of Iron Bridges and Roofs._ By AUGUST
RITTER, Ph.D., Professor at the Polytechnic School at Aix-la-Chapelle.
Translated from the third German edition, by H. R. SANKEY, Capt. R.E.
With 500 _illustrations_, 8vo, cloth, 15_s._


_The Elementary Principles of Carpentry._ By THOMAS TREDGOLD. Revised
from the original edition, and partly re-written, by JOHN THOMAS HURST.
Contained in 517 pages of letter-press, and _illustrated with 48 plates
and 150 wood engravings_. Sixth edition, reprinted from the third, crown
8vo, cloth, 12_s._ 6_d._

     Section I. On the Equality and Distribution of Forces--Section II.
     Resistance of Timber--Section III. Construction of Floors--Section
     IV. Construction of Roofs--Section V. Construction of Domes and
     Cupolas--Section VI. Construction of Partitions--Section VII.
     Scaffolds, Staging, and Gantries--Section VIII. Construction of
     Centres for Bridges--Section IX. Coffer-dams, Shoring, and
     Strutting--Section X. Wooden Bridges and Viaducts--Section XI.
     Joints, Straps, and other Fastenings--Section XII. Timber.


_The Builder's Clerk_: a Guide to the Management of a Builder's
Business. By THOMAS BALES. Fcap. 8vo, cloth, 1_s._ 6_d._


_Our Factories, Workshops, and Warehouses_: their Sanitary and
Fire-Resisting Arrangements. By _B. H. Thwaite_, Assoc. Mem. Inst. C.E.
_With 183 wood engravings_, crown 8vo, cloth, 9_s._


_Gold_: Its Occurrence and Extraction, embracing the Geographical and
Geological Distribution and the Mineralogical Characters of Gold-bearing
rocks; the peculiar features and modes of working Shallow Placers,
Rivers, and Deep Leads; Hydraulicing; the Reduction and Separation of
Auriferous Quartz; the treatment of complex Auriferous ores containing
other metals; a Bibliography of the subject and a Glossary of Technical
and Foreign Terms. By _Alfred G. Lock_, F.R.G.S. _With numerous
illustrations and maps_, 1250 pp., super-royal 8vo, cloth, 2_l._ 12_s._
6_d._


_Iron Roofs_: Examples of Design, Description. _Illustrated with 64
Working Drawings of Executed Roofs._ By ARTHUR T. WALMISLEY, Assoc. Mem.
Inst. C.E. Second edition, revised, imp. 4to, half-morocco, 3_l._ 3_s._


_A History of Electric Telegraphy_, to the Year 1837. Chiefly compiled
from Original Sources, and hitherto Unpublished Documents, by J. J.
FAHIE, Mem. Soc. of Tel. Engineers, and of the International Society of
Electricians, Paris. Crown 8vo, cloth, 9_s._


_Spons' Information for Colonial Engineers._ Edited by J. T. HURST. Demy
8vo, sewed.

     No. 1, Ceylon. By ABRAHAM DEANE, C.E. 2_s._ 6_d._

     CONTENTS:

     Introductory Remarks--Natural Productions--Architecture and
     Engineering--Topography, Trade, and Natural History--Principal
     Stations--Weights and Measures, etc., etc.

     No. 2. Southern Africa, including the Cape Colony, Natal, and the
     Dutch Republics. By HENRY HALL, F.R.G.S., F.R.C.I. With Map. 3_s._
     6_d._

     CONTENTS:

     General Description of South Africa--Physical Geography with
     reference to Engineering Operations--Notes on Labour and Material
     in Cape Colony--Geological Notes on Rock Formation in South
     Africa--Engineering Instruments for Use in South Africa--Principal
     Public Works in Cape Colony: Railways, Mountain Roads and Passes,
     Harbour Works, Bridges, Gas Works, Irrigation and Water Supply,
     Lighthouses, Drainage and Sanitary Engineering, Public Buildings,
     Mines--Table of Woods in South Africa--Animals used for Draught
     Purposes--Statistical Notes--Table of Distances--Rates of Carriage,
     etc.

     No. 3. India. By F. C. DANVERS, Assoc. Inst. C.E. With Map. 4_s._
     6_d._

     CONTENTS:

     Physical Geography of India--Building Materials--Roads--Railways--
     Bridges--Irrigation--River Works--Harbours--Lighthouse Buildings--
     Native Labour--The Principal Trees of India--Money--Weights and
     Measures--Glossary of Indian Terms, etc.


_A Practical Treatise on Coal Mining._ By GEORGE G. ANDRE, F.G.S.,
Assoc. Inst. C.E., Member of the Society of Engineers. _With 82
lithographic plates._ 2 vols., royal 4to, cloth, 3_l._ 12_s._


_A Practical Treatise on Casting and Founding_, including descriptions
of the modern machinery employed in the art. By N. E. SPRETSON,
Engineer. Third edition, with 82 _plates_ drawn to scale, 412 pp., demy
8vo, cloth, 18_s._


_The Depreciation of Factories and their Valuation._ By EWING MATHESON,
M. Inst. C.E. 8vo, cloth, 6_s._


_A Handbook of Electrical Testing._ By H. R. KEMPE, M.S.T.E. Fourth
edition, revised and enlarged, crown 8vo, cloth, 16_s._


_Gas Works_: their Arrangement, Construction, Plant, and Machinery. By
F. COLYER, M. Inst. C.E. _With 31 folding plates_, 8vo, cloth, 24_s._


_The Clerk of Works_: a Vade-Mecum for all engaged in the
Superintendence of Building Operations. By G. G. HOSKINS, F.R.I.B.A.
Third edition, fcap. 8vo, cloth, 1_s._ 6_d._


_American Foundry Practice_: Treating of Loam, Dry Sand, and Green Sand
Moulding, and containing a Practical Treatise upon the Management of
Cupolas, and the Melting of Iron. By T. D. WEST, Practical Iron Moulder
and Foundry Foreman. Second edition, _with numerous illustrations_,
crown 8vo, cloth, 10_s._ 6_d._


_The Maintenance of Macadamised Roads._ By T. CODRINGTON, M.I.C.E,
F.G.S., General Superintendent of County Roads for South Wales. 8vo,
cloth, 6_s._


_Hydraulic Steam and Hand Power Lifting and Pressing Machinery._ By
FREDERICK COLYER, M. Inst. C.E., M. Inst. M.E. _With 73 plates_, 8vo,
cloth, 18_s._


_Pumps and Pumping Machinery._ By F. COLYER, M.I.C.E., M.I.M.E. _With 23
folding plates_, 8vo, cloth, 12_s._ 6_d._


_Pumps and Pumping Machinery._ By F. COLYER. Second Part. _With 11 large
plates_, 8vo, cloth, 12_s._ 6_d._


_A Treatise on the Origin, Progress, Prevention, and Cure of Dry Rot in
Timber_; with Remarks on the Means of Preserving Wood from Destruction
by Sea-Worms, Beetles, Ants, etc. By THOMAS ALLEN BRITTON, late Surveyor
to the Metropolitan Board of Works, etc., etc. _With 10 plates_, crown
8vo, cloth, 7_s._ 6_d._


_The Municipal and Sanitary Engineer's Handbook._ By H. PERCY BOULNOIS,
Mem. Inst. C.E., Borough Engineer, Portsmouth. _With numerous
illustrations_, demy 8vo, cloth, 12_s._ 6_d._

     CONTENTS:

     The Appointment and Duties of the Town Surveyor--Traffic--
     Macadamised Roadways--Steam Rolling--Road Metal and Breaking--
     Pitched Pavements--Asphalte--Wood Pavements--Footpaths--Kerbs and
     Gutters--Street Naming and Numbering--Street Lighting--Sewerage--
     Ventilation of Sewers--Disposal of Sewage--House Drainage--
     Disinfection--Gas and Water Companies, etc., Breaking up Streets--
     Improvement of Private Streets--Borrowing Powers--Artizans' and
     Labourers' Dwellings--Public Conveniences--Scavenging, including
     Street Cleansing--Watering and the Removing of Snow--Planting
     Street Trees--Deposit of Plans--Dangerous Buildings--Hoardings--
     Obstructions--Improving Street Lines--Cellar Openings--Public
     Pleasure Grounds--Cemeteries--Mortuaries--Cattle and Ordinary
     Markets--Public Slaughter-houses, etc.--Giving numerous Forms
     of Notices, Specifications, and General Information upon these
     and other subjects of great importance to Municipal Engineers and
     others engaged in Sanitary Work.


_Metrical Tables._ By G. L. MOLESWORTH, M.I.C.E. 32mo, cloth, 1_s._
6_d._

     CONTENTS:

     General--Linear Measures--Square Measures--Cubic Measures--Measures
     of Capacity--Weights--Combinations--Thermometers.


_Elements of Construction for Electro-Magnets._ By Count TH. DU MONCEL,
Mem. de I'lnstitut de France. Translated from the French by C. J.
WHARTON. Crown 8vo, cloth, 4_s._ 6_d._


_Practical Electrical Units Popularly Explained_, with _numerous
illustrations_ and Remarks. By JAMES SWINBURNE, late of J. W. Swan and
Co., Paris, late of Brush-Swan Electric Light Company, U.S.A. 18mo,
cloth, 1_s._ 6_d._


_A Treatise on the Use of Belting for the Transmission of Power._ By J.
H. COOPER. Second edition, _illustrated_, 8vo, cloth, 15_s._


_A Pocket-Book of Useful Formulae and Memoranda for Civil and Mechanical
Engineers._ By GUILFORD L. MOLESWORTH, Mem. Inst. C.E., Consulting
Engineer to the Government of India for State Railways. _With numerous
illustrations_, 744 pp. Twenty-first edition, revised and enlarged,
32mo, roan, 6_s._

     SYNOPSIS OF CONTENTS:

     Surveying, Levelling, etc.--Strength and Weight of Materials--
     Earthwork, Brickwork, Masonry, Arches, etc.--Struts, Columns,
     Beams, and Trusses--Flooring, Roofing, and Roof Trusses--Girders,
     Bridges, etc.--Railways and Roads--Hydraulic Formulae--Canals,
     Sewers, Waterworks, Docks--Irrigation and Breakwaters--Gas,
     Ventilation, and Warming--Heat, Light, Colour, and Sound--Gravity:
     Centres, Forces, and Powers--Millwork, Teeth of Wheels, Shafting,
     etc.--Workshop Recipes--Sundry Machinery--Animal Power--Steam and
     the Steam Engine--Water-power, Water-wheels, Turbines, etc.--Wind
     and Windmills--Steam Navigation, Ship Building, Tonnage, etc.--
     Gunnery, Projectiles, etc.--Weights, Measures, and Money--
     Trigonometry, Conic Sections, and Curves--Telegraphy--Mensuration--
     Tables of Areas and Circumference, and Arcs of Circles--Logarithms,
     Square and Cube Roots, Powers--Reciprocals, etc.--Useful Numbers--
     Differential and Integral Calculus--Algebraic Signs--Telegraphic
     Construction and Formulae.


_Hints on Architectural Draughtsmanship._ By G. W. TUXFORD HALLATT.
Fcap. 8vo, cloth, 1_s._ 6_d._


_Spons' Tables and Memoranda for Engineers_; selected and arranged by J.
T. HURST, C.E., Author of 'Architectural Surveyors' Handbook,' 'Hurst's
Tredgold's Carpentry,' etc. Ninth edition, 64mo, roan, gilt edges,
1_s._; or in cloth case, 1_s._ 6_d._

     This work is printed in a pearl type, and is so small, measuring
     only 2-1/2 in. by 1-1/4 in. by 1/4 in. thick, that it may be easily
     carried in the waistcoat pocket.

     "It is certainly an extremely rare thing for a reviewer to be
     called upon to notice a volume measuring but 2-1/2 in. by 1-1/4
     in., yet these dimensions faithfully represent the size of the
     handy little book before us. The volume--which contains 118 printed
     pages, besides a few blank pages for memoranda--is, in fact, a true
     pocket-book, adapted for being carried in the waistcoat pocket, and
     containing a far greater amount and variety of information than
     most people would imagine could be compressed into so small a
     space.... The little volume has been compiled with considerable
     care and judgment, and we can cordially recommend it to our readers
     as a useful little pocket companion."--_Engineering._


_A Practical Treatise on Natural and Artificial Concrete, its Varieties
and Constructive Adaptations._ By HENRY REID, Author of the 'Science and
Art of the Manufacture of Portland Cement.' New Edition, _with 59
woodcuts and 5 plates_, 8vo, cloth, 15_s._


_Notes on Concrete and Works in Concrete_; especially written to assist
those engaged upon Public Works. By JOHN NEWMAN, Assoc. Mem. Inst. C.E.,
crown 8vo, cloth, 4_s._ 6_d._


_Electricity as a Motive Power._ By Count TH. DU MONCEL, Membre de
l'Institut de France, and FRANK GERALDY, Ingenieur des Ponts et
Chaussees. Translated and Edited, with Additions, by C. J. WHARTON,
Assoc. Soc. Tel. Eng. and Elec. _With 113 engravings and diagrams_,
crown 8vo, cloth, 7_s._ 6_d._


_Treatise on Valve-Gears_, with special consideration of the
Link-Motions of Locomotive Engines. By Dr. GUSTAV ZEUNER, Professor of
Applied Mechanics at the Confederated Polytechnikum of Zurich.
Translated from the Fourth German Edition, by Professor J. F. KLEIN,
Lehigh University, Bethlehem, Pa. _Illustrated_, 8vo, cloth, 1_2s._
6_d._


_The French-Polisher's Manual._ By a French-Polisher; containing Timber
Staining, Washing, Matching, Improving, Painting, Imitations, Directions
for Staining, Sizing, Embodying, Smoothing, Spirit Varnishing,
French-Polishing, Directions for Re-polishing. Third edition, royal
32mo, sewed, 6_d._


_Hops, their Cultivation, Commerce, and Uses in various Countries._ By
P. L. SIMMONDS. Crown 8vo, cloth, 4_s._ 6_d._


_The Principles of Graphic Statics._ By GEORGE SYDENHAM CLARKE, Capt.
Royal Engineers. _With 112 illustrations._ 4to, cloth, 12_s._ 6_d._


_Dynamo-Electric Machinery_: A Manual for Students of Electro-technics.
By SILVANUS P. THOMPSON, B.A., D.Sc., Professor of Experimental Physics
in University College, Bristol, etc., etc. Second edition,
_illustrated_, 8vo, cloth, 12_s._ 6_d._


_Practical Geometry, Perspective, and Engineering Drawing_; a Course of
Descriptive Geometry adapted to the Requirements of the Engineering
Draughtsman, including the determination of cast shadows and Isometric
Projection, each chapter being followed by numerous examples; to which
are added rules for Shading, Shade-lining, etc., together with practical
instructions as to the Lining, Colouring, Printing, and general
treatment of Engineering Drawings, with a chapter on drawing
Instruments. By GEORGE S. CLARKE, Capt. R.E. Second edition, _with 21
plates_. 2 vols., cloth, 10_s._ 6_d._


_The Elements of Graphic Statics._ By Professor KARL VON OTT, translated
from the German by G. S. CLARKE, Capt. R.E., Instructor in Mechanical
Drawing, Royal Indian Engineering College. _With 93 illustrations_,
crown 8vo, cloth, 5_s._


_A Practical Treatise on the Manufacture and Distribution of Coal Gas._
By WILLIAM RICHARDS. Demy 4to, with _numerous wood engravings and 29
plates_, cloth, 28_s._

     SYNOPSIS OF CONTENTS:

     Introduction--History of Gas Lighting--Chemistry of Gas
     Manufacture, by Lewis Thompson, Esq., M.R.C.S.--Coal, with
     Analyses, by J. Paterson, Lewis Thompson, and G. R. Hislop,
     Esqrs.--Retorts, Iron and Clay--Retort Setting--Hydraulic Main--
     Condensers--Exhausters--Washers and Scrubbers--Purifiers--
     Purification--History of Gas Holder--Tanks, Brick and Stone,
     Composite, Concrete, Cast-iron, Compound Annular Wrought-iron--
     Specifications--Gas Holders--Station Meter--Governor--
     Distribution--Mains--Gas Mathematics, or Formulae for the
     Distribution of Gas, by Lewis Thompson, Esq.--Services--Consumers'
     Meters--Regulators--Burners--Fittings--Photometer--Carburization
     of Gas--Air Gas and Water Gas--Composition of Coal Gas, by Lewis
     Thompson, Esq.--Analyses of Gas--Influence of Atmospheric Pressure
     and Temperature on Gas--Residual Products--Appendix--Description
     of Retort Settings, Buildings, etc., etc.


_The New Formula for Mean Velocity of Discharge of Rivers and Canals._
By W. R. KUTTER. Translated from articles in the 'Cultur-Ingenieur,' by
LOWIS D'A. JACKSON, Assoc. Inst. C.E. 8vo, cloth, 12_s._ 6_d._


_The Practical Millwright and Engineer's Ready Reckoner_; or Tables for
finding the diameter and power of cog-wheels, diameter, weight, and
power of shafts, diameter and strength of bolts, etc. By THOMAS DIXON.
Fourth edition, 12mo, cloth, 3_s._


_Tin_: Describing the Chief Methods of Mining, Dressing and Smelting it
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_Breweries and Maltings_: their Arrangement, Construction, Machinery,
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_Electrolysis_: a Practical Treatise on Nickeling, Coppering, Gilding,
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     most recent arrangements of Horizontal, Vertical, Beam, Pumping,
     Winding, Portable, Semi-portable, Corliss, Allen, Compound, and
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_A Practical Treatise on the Science of Land and Engineering Surveying,
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     Mining and Town Surveying--Railroad Surveying--Mapping--Division
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_Health and Comfort in House Building, or Ventilation with Warm Air by
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_Treatise on Watchwork, Past and Present._ By the Rev. H. L. NELTHROPP,
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_Spons' Dictionary of Engineering, Civil, Mechanical, Military, and
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_Notes in Mechanical Engineering._ Compiled principally for the use of
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_Proceedings of the National Conference of Electricians, Philadelphia_,
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_Dynamo-Electricity_, its Generation, Application, Transmission,
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_Domestic Electricity for Amateurs._ Translated from the French of E.
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_Wrinkles in Electric Lighting._ By VINCENT STEPHEN. _With
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     Silk Manufactures, 9 pp. 11 figs.
     Skins, 5 pp.
     Small Wares, 4 pp.
     Soap and Glycerine, 39 pp. 45 figs.
     Spices, 16 pp.
     Sponge, 5 pp.
     Starch, 9 pp. 10 figs.
     Sugar, 155 pp.       134 figs.
     Sulphur.
     Tannin, 18 pp.
     Tea, 12 pp.
     Timber, 13 pp.
     Varnish, 15 pp.
     Vinegar, 5 pp.
     Wax, 5 pp.
     Wool, 2 pp.
     Woollen Manufactures, 58 pp. 39 figs.

  London: E. & F. N. SPON, 125, Strand.
  New York: 35, Murray Street.



  Crown 8vo, cloth, with illustrations, 5_s._

  WORKSHOP RECEIPTS,
  FIRST SERIES.

  BY ERNEST SPON.

     SYNOPSIS OF CONTENTS.

     Bookbinding.
     Bronzes and Bronzing.
     Candles.
     Cement.
     Cleaning.
     Colourwashing.
     Concretes.
     Dipping Acids.
     Drawing Office Details.
     Drying Oils.
     Dynamite.
     Electro-Metallurgy--(Cleaning, Dipping, Scratch-brushing,
       Batteries, Baths, and Deposits of every description).
     Enamels.
     Engraving on Wood, Copper, Gold, Silver, Steel, and Stone.
     Etching and Aqua Tint.
     Firework Making--(Rockets, Stars, Rains, Gerbes, Jets,
       Tourbillons, Candles, Fires, Lances, Lights, Wheels,
       Fire-balloons, and minor Fireworks).
     Fluxes.
     Foundry Mixtures.
     Freezing.
     Fulminates.
     Furniture Creams, Oils, Polishes, Lacquers, and Pastes.
     Gilding.
     Glass Cutting, Cleaning, Frosting, Drilling, Darkening, Bending,
       Staining, and Painting.
     Glass Making.
     Glues.
     Gold.
     Graining.
     Gums.
     Gun Cotton.
     Gunpowder.
     Horn Working.
     Indiarubber.
     Japans, Japanning, and kindred processes.
     Lacquers.
     Lathing.
     Lubricants.
     Marble Working.
     Matches.
     Mortars.
     Nitro-Glycerine.
     Oils.
     Paper.
     Paper Hanging.
     Painting in Oils, in Water Colours, as well as Fresco, House,
       Transparency, Sign, and Carriage Painting.
     Photography.
     Plastering.
     Polishes.
     Pottery--(Clays, Bodies, Glazes, Colours, Oils, Stains, Fluxes,
       Enamels, and Lustres).
     Scouring.
     Silvering.
     Soap.
     Solders.
     Tanning.
     Taxidermy.
     Tempering Metals.
     Treating Horn, Mother-o'-Pearl, and like substances.
     Varnishes, Manufacture and Use of.
     Veneering.
     Washing.
     Waterproofing.
     Welding.

  Besides Receipts relating to the lesser Technological matters and
  processes, such as the manufacture and use of Stencil Plates,
  Blacking, Crayons, Paste, Putty, Wax, Size, Alloys, Catgut, Tunbridge
  Ware, Picture Frame and Architectural Mouldings, Compos, Cameos, and
  others too numerous to mention.

  London: E. & F. N. SPON, 125, Strand.
  New York: 35, Murray Street.



  Crown 8vo, cloth, 485 pages, with illustrations, 5_s._

  WORKSHOP RECEIPTS,
  SECOND SERIES.

  BY ROBERT HALDANE.

     SYNOPSIS OF CONTENTS.

     Acidimetry and Alkalimetry.
     Albumen.
     Alcohol.
     Alkaloids.
     Baking-powders.
     Bitters.
     Bleaching.
     Boiler Incrustations.
     Cements and Lutes.
     Cleansing.
     Confectionery.
     Copying.
     Disinfectants.
     Dyeing, Staining, and Colouring.
     Essences.
     Extracts.
     Fireproofing.
     Gelatine, Glue, and Size.
     Glycerine.
     Gut.
     Hydrogen peroxide.
     Ink.
     Iodine.
     Iodoform.
     Isinglass.
     Ivory substitutes.
     Leather.
     Luminous bodies.
     Magnesia.
     Matches.
     Paper.
     Parchment.
     Perchloric acid.
     Potassium oxalate.
     Preserving.

  =Pigments, Paint, and Painting=: embracing the preparation of
  _Pigments_, including alumina lakes, blacks (animal, bone, Frankfort,
  ivory, lamp, sight, soot), blues (antimony, Antwerp, cobalt, caeruleum,
  Egyptian, manganate, Paris, Peligot, Prussian, smalt, ultramarine),
  browns (bistre, hinau, sepia, sienna, umber, Vandyke), greens (baryta,
  Brighton, Brunswick, chrome, cobalt, Douglas, emerald, manganese,
  mitis, mountain, Prussian, sap, Scheele's, Schweinfurth, titanium,
  verdigris, zinc), reds (Brazilwood lake, carminated lake, carmine,
  Cassius purple, cobalt pink, cochineal lake, colcothar, Indian red,
  madder lake, red chalk, red lead, vermilion), whites (alum, baryta,
  Chinese, lead sulphate, white lead--by American, Dutch, French,
  German, Kremnitz, and Pattinson processes, precautions in making, and
  composition of commercial samples--whiting, Wilkinson's white, zinc
  white), yellows (chrome, gamboge, Naples, orpiment, realgar, yellow
  lakes); _Paint_ (vehicles, testing oils, driers, grinding, storing,
  applying, priming, drying, filling, coats, brushes, surface,
  water-colours, removing smell, discoloration; miscellaneous paints--
  cement paint for carton-pierre, copper paint, gold paint, iron paint,
  lime paints, silicated paints, steatite paint, transparent paints,
  tungsten paints, window paint, zinc paints); _Painting_ (general
  instructions, proportions of ingredients, measuring paint work;
  carriage painting--priming paint, best putty, finishing colour,
  cause of cracking, mixing the paints, oils, driers, and colours,
  varnishing, importance of washing vehicles, re-varnishing, how to
  dry paint; woodwork painting).

  London: E. & F. N. SPON, 125, Strand.
  New York: 35, Murray Street.



  JUST PUBLISHED.

  Crown 8vo, cloth, 480 pages, with 183 illustrations, 5_s._

  WORKSHOP RECEIPTS,
  THIRD SERIES.

  BY C. G. WARNFORD LOCK.

  Uniform with the First and Second Series.

     SYNOPSIS OF CONTENTS.

     Alloys.
     Aluminium.
     Antimony.
     Barium.
     Beryllium.
     Bismuth.
     Cadmium.
     Caeesium.
     Calcium.
     Cerium.
     Chromium.
     Cobalt.
     Copper.
     Didymium.
     Electrics.
     Enamels and Glazes.
     Erbium.
     Gallium.
     Glass.
     Gold.
     Indium.
     Iridium.
     Iron and Steel.
     Lacquers and Lacquering.
     Lanthanum.
     Lead.
     Lithium.
     Lubricants.
     Magnesium.
     Manganese.
     Mercury.
     Mica.
     Molybdenum.
     Nickel.
     Niobium.
     Osmium.
     Palladium.
     Platinum.
     Potassium.
     Rhodium.
     Rubidium.
     Ruthenium.
     Selenium.
     Silver.
     Slag.
     Sodium.
     Strontium.
     Tantalum.
     Terbium.
     Thallium.
     Thorium.
     Tin.
     Titanium.
     Tungsten.
     Uranium.
     Vanadium.
     Yttrium.
     Zinc.
     Zirconium.

  London: E. & F. N. SPON, 125, Strand.
  New York: 35, Murray Street.



  WORKSHOP RECEIPTS,
  FOURTH SERIES,
  DEVOTED MAINLY TO HANDICRAFTS & MECHANICAL SUBJECTS.

  BY C. G. WARNFORD LOCK.

  250 Illustrations, with Complete Index, and a General Index to the
  Four Series, 5_s._

     Waterproofing--rubber goods, cuprammonium processes, miscellaneous
     preparations.

     Packing and Storing articles of delicate odour or colour, of a
     deliquescent character, liable to ignition, apt to suffer from
     insects or damp, or easily broken.

     Embalming and Preserving anatomical specimens.

     Leather Polishes.

     Cooling Air and Water, producing low temperatures, making ice,
     cooling syrups and solutions, and separating salts from liquors by
     refrigeration.

     Pumps and Siphons, embracing every useful contrivance for raising
     and supplying water on a moderate scale, and moving corrosive,
     tenacious, and other liquids.

     Desiccating--air-and water-ovens, and other appliances for drying
     natural and artificial products.

     Distilling--water, tinctures, extracts, pharmaceutical
     preparations, essences, perfumes, and alcoholic liquids.

     Emulsifying as required by pharmacists and photographers.

     Evaporating--saline and other solutions, and liquids demanding
     special precautions.

     Filtering--water, and solutions of various kinds.

     Percolating and Macerating.

     Electrotyping.

     Stereotyping by both plaster and paper processes.

     Bookbinding in all its details.

     Straw Plaiting and the fabrication of baskets, matting, etc.

     Musical Instruments--the preservation, tuning, and repair of
     pianos, harmoniums, musical boxes, etc.

     Clock and Watch Mending--adapted for intelligent amateurs.

     Photography--recent development in rapid processes, handy
     apparatus, numerous recipes for sensitizing and developing
     solutions, and applications to modern illustrative purposes.

  London: E. & F. N. SPON, 125, Strand.
  New York: 35, Murray Street.



  JUST PUBLISHED.

  In demy 8vo, cloth, 600 pages, and 1420 Illustrations, 6_s._

  SPONS'
  MECHANICS' OWN BOOK;

  A MANUAL FOR HANDICRAFTSMEN AND AMATEURS.

     CONTENTS.

     Mechanical Drawing--Casting and Founding in Iron, Brass, Bronze,
     and other Alloys--Forging and Finishing Iron--Sheetmetal
     Working--Soldering, Brazing, and Burning--Carpentry and Joinery,
     embracing descriptions of some 400 Woods, over 200 Illustrations of
     Tools and their uses, Explanations (with Diagrams) of 116 joints
     and hinges, and Details of Construction of Workshop appliances,
     rough furniture, Garden and Yard Erections, and House Building--
     Cabinet-Making and Veneering--Carving and Fretcutting--Upholstery--
     Painting, Graining, and Marbling--Staining Furniture, Woods,
     Floors, and Fittings--Gilding, dead and bright, on various
     grounds--Polishing Marble, Metals, and Wood--Varnishing--Mechanical
     movements, illustrating contrivances for transmitting motion--
     Turning in Wood and Metals--Masonry, embracing Stonework,
     Brickwork, Terracotta, and Concrete--Roofing with Thatch, Tiles,
     Slates, Felt, Zinc, &c.--Glazing with and without putty, and lead
     glazing--Plastering and Whitewashing--Paper-hanging--Gas-fitting--
     Bell-hanging, ordinary and electric Systems--Lighting--Warming--
     Ventilating--Roads, Pavements, and Bridges--Hedges, Ditches, and
     Drains--Water Supply and Sanitation--Hints on House Construction
     suited to new countries.

  London: E. & F. N. SPON, 125, Strand.
  New York: 35, Murray Street.





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