mantle, etc.
It is noticed that the brilliant light given by a new burner
does not last, the light after a fortnight probably commencing to
decrease ; if kept in use, the mantle top becomes coated with soot
and 'a smoky flame issues. The burners go wrong in a much
shorter time if used in a room in which a fire is constantly
burning. The cause of this is simply dust, which is drawn in at
the air-holes and carried up the Bunsen tube. It cannot pass
away owing to the gauze, to which it adheres, thus preventing
the gas getting away quickly enough to draw in the proper
amount of air. To remedy this, take off the mantle and, with
a small brush (an old nail- or tooth-brush), remove the dirt,
blowing through the gauze afterwards. Then replace the mantle,
clean and replace the chimney, unscrew the Bunsen tube, and
brush the nipple clean. Blow the dust from the tube and then
refix the top. If the mantle is covered with soot, leave the gas
half on until the soot is removed. To keep the burners at their
best, this process should be done at least monthly. If the burners
are in a dusty place they will require more frequent cleaning.
Failure of the bye-pass is a common fault, even in new
burners. The bye-pass light may go out after the gas is turned
on. In a new burner this is often caused by one of the two set-
screws on the side of the burner being inserted too far ; in this
case, after unscrewing a complete turn, the burner will most likely
work. It is sometimes necessary to take out both screws and to
remove the grease adhering inside the end of the hole.
127
CHAPTER VIII.
GAS-FITTING IN WORKSHOPS AND THEATRES.
IN fitting workshops with gas, it is important that strong
materials be employed, and it is desirable to use iron pipes
throughout. Where a row of benches is fixed upon each side of
a workshop, it is usual to run a pipe along just below the ceiling,
with tees between each window ; from these a small pipe is
carried down to either a single or double swing iron bracket.
Some firms who make gas-fittings supply iron brackets, but they
can be made up quickly from the brass fittings and short pieces
of iron pipe purchasable from any dealer. Brass swivels wear
considerably better than those that are made of iron, and do not
corrode and stick in the working parts.
When the lights are to be fitted, say, down the middle of a
workshop where lathes or other machine tools are used, the
only brass parts are the taps and burner elbows, the ordinary
iron tee being very suitable for the centre of the pendant.
Where more than one floor is to be lighted, fix on the supply
pipe a governor for regulating the quantity of gas delivered ;
otherwise the pressure due to the height of the upper floors
will cause a lowering of the light in the ground floor or base-
ment. It is also an advantage to have each floor separately
supplied from the main, so that each floor may be shut off
entirely without interfering with the others ; and if a separate
meter be supplied for each floor, the quantity of gas consumed in
proportion to the work done after dark may be checked, and any
escape noted. Where a pipe falls, a pipe syphon or syphon-box
should be fixed, as the temperature is subject to extreme changes
and the quantity of condensation is much greater than in private
houses.
When the pipes are run through the floor and up the legs of
the lathes or other machinery, it is usual to bend the pipe to the
128 PRACTICAL GAS-FITTING.
exact curves taken by the machine, and to fix the pipe in its
place by means of bands of iron bent to the curve of the pipe,
and fixed to the machine by two small set screws. These bands
may also be found useful in fitting up houses where the nature
of the wall or floor will not permit the use of the ordinary pipe-
hook.
It is often found necessary to fit up in a workshop over each
machine a bracket arranged so as to move in any direction to suit
the convenience of the workman. One way of making these
fittings is to make the elbows of the brackets of two double swing
swivels one upright and one on its side. Another way is to
have two lines of pipes from the support, and to connect both at
each end to double swivels ; whilst between the upper and lower
pipe, and laid at an angle, is a thin bar, which is fixed on to the
upper pipe, and can be clamped to the lower one when the exact
position required has been obtained. This form of bracket is
useful in drawing offices, where the burner and shade commonly
in use cause the other pattern of bracket to gradually fall down-
wards on to the table ; whereas the second arrangement always
keeps parallel, and, if tightly clamped, cannot change its position
without breaking the thin metal bar, which should be made
sufficiently strong to withstand the strain due to the weight
of the heaviest burner, chimney, and shade likely to be placed
upon it.
In making brackets and pendants, it is convenient to know a
quick and efficient way to bend iron pipes. The exact shape
required having been drawn full size upon paper, the latter is
tacked or pasted on to a rough board. Strong cut nails are then
driven in to follow the desired curve, the nails being half the
outside diameter of the pipe from the drawn line, so that the
centre of the pipe, when bent, may lie directly over the drawn
line. The iron pipe is heated in a forge fire or in a draw-furnace ;
the latter heats the pipe equally over the length required. The
end is inserted between the lines of nails, and, with the aid of a
pair of pliers, is quickly made to follow the curves indicated by
the nails. Nails are not necessary on the outer side of the
curves, except at the starting point, where a firm grip of the pipe
must be insured. Where many pipes are to be bent to the same
shape, the board is replaced by a square plate, with holes all
over it, cast- or wrought-iron curves replacing the nails. The
saving in time and the accuracy of the bending soon repay the
GAS-FITTING IN WORKSHOPS. 129
additional outlay. In bending iron pipe, proceed gradually, and
make only small curves at a time, or the pipe will collapse.
For workshop brackets, the ordinary circular back or wooden
pattress is not employed generally, metal backs being found
stronger and more suitable. These metal backs are supplied with
the fittings, and are drilled and countersunk ready for erection,
space being left for the pipe to screw into the top of the swivel
joint. A metal back makes a strong job, and answers every
purpose where very neat finish is not necessary.
In all workshops ventilation is a prime requisite, and must be
provided for, more especially where the rooms are low and a
considerable number of workmen and gas lights are employed.
Gas is an excellent draught inductor; -an ordinary batswing or
union jet burner (see pp. 99 to 107) consuming 1 cub. ft. of gas pel-
hour, when placed in a 6-in. ventilating tube 12 ft. long, will
cause 2,460 cub. ft. of air per hour to pass up the tube ; and this
induced draught can be easily adapted for the removal of the
heated and vitiated air from the upper portion of the room.
Each person present will give off per hour about 17'7 cub. ft. of air,
of which from '6 to '8 of a cubic foot will be carbonic acid (CO 2 ) ;
the amount of CO 2 evolved from the combustion of coal gas
practically is equal to one-half the quantity of gas burnt ; and an
ordinary gas burner may be considered as being equivalent to at
least three adults in its effect upon the atmosphere. The air
space required in a workshop is 250 cub. ft. for each person
during the day and 400 ft. at night. Again, 500 cub. ft. of fresh
air per person should be delivered into a room during each hour,
and therefore the same quantity of vitiated air must be drawn
away by some means ; no method is more suitable or so effective
as the one above proposed, in which a lighted gas burner is
enclosed by a ventilating shaft. A well-constructed Sun burner
(see pp. 115 and 116) has an excellent effect upon the ventilation
of a room, workshop, or hall, when a properly arranged vertical
shaft, usually of sheet iron, is carried up through the roof, and
will at the same time assist greatly in the general illumination of
the apartment.
Many of the above remarks are equally if not more applicable
to the fitting up of theatres and places of public entertainment,
whose ventilation is an important matter. In these places, the
object to be attained is complete ventilation without loss of
lighting effect,
130
PRACTICAL GAS-FITTING.
In theatres, it is usual to bring the supply up on the wall on
the prompt or right-hand side of the stage when looking from the
auditorium, and there to branch off with a tee which has on each
side other tees fixed as close together as possible, and all
pointing upwards, From the outlets of these run the various
supplies to the different parts of the house. This arrangement
provides against fire, and is indispensable when it is necessary to
lower lights in certain portions only of the stage and auditorium.
Each pipe has a cock upon it, and also a bye-pass with a small
tap, so that, on turning down the lights, sufficient gas flows
through the bye-pass to keep only the smallest flicker in each
Fig. 101. Gas Cocks and Bye-passes for Theatre.
burner, and then, when the cock is turned on again, the lights are
quickly at their full power without the trouble of re-lighting.
The usual way of fixing these bye-passes is to screw an elbow
nose-piece into a hole drilled and tapped in the pipe below the
cock, and to screw another in the pipe above the cock, taking
care that the distance between the two ends, when turned
towards each other, is the exact distance to suit a small cock with
a union on one end. Fig. 101 explains the arrangement. Each
supply pipe is labelled with the name of the portion of the house
which is being served by it, so that the gas may be turned off or
on as may be required.
Fig. 102 illustrates another form of bye-pass arrangement. It
is fixed about 5 ft. from the floor of the stage, as handy as
possible. The reservoir is filled direct from the main by the
GAS-FITTING IN THEATRES.
131
pipe L, whose size depends principally upon the quantity of gas
required for the stage. The footlights, gas battens, and side-
lights are all kept separate : E controls the footlights ; F, side-
lights ; G, batten No. 1 ; H, batten No. 2 ; I, batten No. 3.
Should there be any lights in the front of the house controlled
from the stage, they should follow batten 3 or 4, as the case may
be, as at K. For a stage with a 15ft. by 20ft. opening, the
reservoir D should be 2 in. gas barrel, reduced to H in.,
with reducing socket on to the main. E, F, G, H, i, K would
be | in. barrel. The letters N N denote the bye-passes of
5- in. barrel tapped into the in. pipes. The taps, of course, must
n't the different sizes. It will be seen at a glance how easy it is to
Fig-. 102. Gas Cocks and Bye-passes for Theatre.
regulate the gas with this arrangement. The bye taps N
must be kept full on ; the main taps may be turned as low as, is
wished right off, if need be, the bye taps preventing the light
going out.
It is usual in theatres to guard all bracket lights in the
passages and corridors, behind the proscenium, leading to the
dressing rooms, property and painting rooms, as well as the lights
in these places and the carpenters' room, by means of a wire
frame made of the same shape and size as an ordinary glass globe.
So many inflammable articles are moved about in a theatre that
every possible precaution has to be employed.
A theatre stage must be lighted so as to ensure a broad open
light, in order that shadows may not be cast on the floor or
scenery by the actors or by any articles on the stage. Thus, a
132
PRACTICAL GAS-FITTING.
stage is lighted from the front, at the top, and at the sides, the
respective names of these lights being : footlights, gas battens,
and sidelights. All these must be protected to prevent accident
from fire.
Stage footlights are formed of 1 in. or 1} in. gas barrel. Strike
a chalk line from one end of the gas barrel to the other, and on
this line holes should be drilled and tapped to receive the ordinary
5 ft. per hour gas burners, which should be from 4 in. to 6 in. apart.
It is often found useful to have more than one row of foot-
lights upon the front of the stage, as in Fig. 103, and then argand
ijv. 103. Stage Footlights-.
burners are usually employed, each row having different-coloured
glasses, so that the light thrown may be of the desired tint (see
Fig. 104). The usual colours employed are green and red, these
forming useful evening effects when the exigencies of the play
require them.
Footlights should be laid about 4 in. or o in. lower than the
stage floor (see Fig. 103), so that the bottom part of the actual
light may be on a level with the floor of the stage to prevent the
floor being in shadow, as it would be if the lights were
too low. The lights are guarded from the view of the audience
by means of a board on edge or a strip of scolloped sheet zinc.
The side nearest the stage is guarded usually by means of brass
GAS-FITTING IN THEATRES.
133
uprights and two or more brass tubes running through them, and
to this is sometimes fastened brass-wire gauze to prevent small
articles and ladies' dresses from catching fire. The trough in
which the gas barrel lies should slope down from the stage The
Fig. 104. Two-row Footlights for Stage.
reflectors are fixed to the front of the stage behind the light (see
A, Fig. 103).
In fixing footlights to a portable stage, the trough should be
hinged to the front of the stage and supported by acute angle
brackets (B, Fig. 105), which allow the trough to hang down to the
Fig. 105.-
-Footlights for Portable
Stage.
Fig-. 106. Stage Foot-
light Reflector.
required level. The reflectors, which are fixed to the upright
front of the trough (see Fig. 103), should be of zinc, and may be
separate or in one length, and scolloped to break the line as desired.
For a portable stage it is usual to have separate reflectors, as
illustrated by Fig. 106, in which c c are two pins soldered in the
zinc for fixing in holes made at regular intervals behind each
134 PRACTICAL GAS-FITTING.
light. The end of the gas barrel is connected by indiarubber
tubing to the main supply pipe.
When rehearsals take place in the daytime and there is
insufficient light to properly watch the action, it is usual to fix up
a T-light standard upon a cock in the centre of tlie footlights.
This standard may be made of 1-in. or l|-in. pipe, and should be
about 4 ft. 6 in. or 5 ft. high. Upon this is screwed a T, and a
piece of pipe about 18 in. to 2 ft. long is screwed into each end of
the T and drilled and tapped, burners being put in about 5 in. or
6 in. apart. This will usually give sufficient light for the
purpose.
The flies, as the portion of the stage where the sky borders
usually hang is called, is lighted by gas battens, the arrangement
consisting of a length of pipe the full width of the stage, with
holes drilled as before described, and burners inserted. These
pipes, which are hung across the stage between each border, are
usually connected to the side and rising supply pipe by means of
rubber tube, and are hung on pulleys so that they can be easily
raised or lowered as required. The gas battens must always be
hung with chains, not only to guard against fire, but also because
the gas so soon rots cord that the batten might fall at any time,
with dangerous results. These lights, again, are guarded with
gauze wire, a sheet of wrought iron being fixed on the side
nearest the border or audience, and the portion facing back
being guarded with iron-wire gauze.
Of sidelights there are either three or four behind each wing.
A perpendicular gas barrel rising from the stage is tapped for the
burners. Sidelights must always be protected with wire globes
(see Fig. 107). Sidelights may be dispensed with, particularly
on a small stage, as they are dangerous in a limited space. Side-
lights are for illuminating the wings, so that the shadow of one
wing shall not fall on the other ; but this effect may be gained by
the proper arrangement of footlights and gas battens.
For lighting the auditorium it is customary to use a large
gasalier, often of very great weight, which requires extremely
careful fixing, as should it fall it might possibly kill many people.
Another system of lighting is by means of a Sun burner (see
pp. 115 and 116) in the centre instead of the gasalier ; and no
matter which arrangement is adopted, a large wrought iron flue
should be constructed, with a cowl on top to prevent down-
draught and the entrance of rain. This not only serves to remove
GAS-FITTING IN THEATRES.
135
the products of combustion from the gas-burners themselves, but,
by the heat engendered, will cause a strong upward current of the
vitiated and warm air from the body of the theatre. In some
cases in which electric light has been fitted in theatres it has
been found necessary to retain the gas centre-light so as to ensure
efficient ventilation.
In the larger theatres it is often found necessary to supple-
ment the centre gasalier by brackets, having two or more arms,
fixed around the fronts of the different circles and galleries ;
these brackets are served generally by a pipe carried from the
Fi^. 107. S;age Sidelights.
general supply centre on the prompt side of the stage, around the
inner side of the balustrade and along the immediate foot of it,
.Where the galleries are deep, brackets are fixed frequently on the
back wall of the auditorium, so that the back portion of the
house is not in absolute darkness, and the way out of the theatre
may be seen more easily. Much, of course, depends on the
amount of money which it is intended to spend upon the
lighting; but every effort should be made to ensure the work
being carried out in a thorough manner, as a great deal of
expense may be saved if the work be properly done in the first
instance.
In almost all large size theatres a gasman is kept on the
136 PRACTICAL GAS-FITTING.
premises, who is answerable for the soundness of the pipes and
fittings ; he is required to test periodically the pipes and fittings
for leakages. This testing must not be done with a light, but at
a time when gas is not being burnt any where in the theatre ; then
by carefully noting if any gas is passing through the meter (by
noting the movement, if any, of the small leaden disc above the
ordinary index, or the small dial if it be a dry meter) it may be
ascertained at once if any gas is being lost through leakages in
the pipes. Another way of detecting leakage is to use a pressure
gauge, and note the pressure (1) when the gauge is first fixed on
the outlet side of the meter (the latter should be closed off), and
(2) after the lapse of say half an hour, when if there be any
leakage the pressure will have fallen to nothing. There are small
meters with large hands for the sole purpose of testing for
leakage, and these, by indicating to a very fine degree, readily
show the rate of leakage. One prominent firm manufactures a
small holder which can be connected to the outlet side of the
cock to the meter, and filled with gas before the gas is shut off ;
then any leakage is made up out of the holder, which lowers
quickly, as it is only made to contain one-tenth of a cubic foot of
gas a scale upon the side showing the actual quantity which has
been required to make up for the gas which may have leaked
away.
In treating upon theatre lighting by any method, only
generalities can be touched upon, as so many different arrange-
ments are now found in theatres and music-halls, each depending
to a large extent on peculiarities of the building and on special
requirement 3.
137
CHAPTER IX.
GAS-FITTING FOR FESTIVAL ILLUMINATIONS.
ON occasions of public rejoicing, it is customary .to illuminate
the streets and the fronts of houses. Gas is the illuminant
commonly employed, and the work of preparing and fixing the
fittings is entrusted, as a rule, to the ordinary gas-fitter. An
effective system of lighting up buildings is to employ rows of pipes,
with arches over doors and windows, the pipes being of wrought
iron of about f in. to 1 in. bore, with holes drilled at intervals of
6 or 9 in., into which holes short pieces of brass pipe are screwed.
These pieces of pipe are bent with the free end upwards to hold
a burner and to support a gallery carrying a moon or globe,
generally of opal, but sometimes of ground glass. This system of
lighting up buildings is very effective when a large front has to
be covered ; but, should rain fall, the hot globes will quickly
crack.
In making gas illuminations with an elaborate motto or
device shown out in flame, the first requirement is a large-sized
pipe, so that an ample supply of gas may reach the burners ; an
insufficient supply of gas will spoil the device. The pipes leading
to the different parts must be sufficiently large and numerous to
ensure plenty of gas at all parts of the design, at (as nearly as
possible) equal pressure.
The design to be attempted may be a star, a crown, initials, or
a portrait, or perhaps a combination of all, with a motto on a
ribbon entwined about the stars, etc. As regards the making of
a star, the first thing is to make a full-sized drawing in ink, on
paper, of the device. This drawing can be enlarged from a small
sketch by means either of a pantograph or of small squares ruled
upon the sketch and also upon the paper in proper proportion,
each square being numbered. The various lines crossing each square
can be easily drawn to cross the similar square on the larger paper.
140 PRACTICAL GAS-FITTING.
blow out parts of the gas-flame. Holes of the same diameter
as are found in a No. 1 or No. l gas-burner will suit the
purpose.
When all is finished, the device should be tried with gas-
under, if practicable, the same pressure as it is likely to receive
when fixed in position and the general effect noticed. Any
holes that are too small can be reamed out, or re drilled, and any
that are too large may be closed by a tap from a hammer.
Perhaps the simplest form of illumination device is one made
by merely bending the copper pipe in the hands. This flexibility
\\\\\j / /'\ ..
''/ W \, V
./... k"V A '.'::-.
Fig 1 . 110. "V.E.I." Monogram for Festival Illumination.
is one of the advantages of copper over iron or brass ; iron,
moreover, has the disadvantage that it rusts, and the holes get
quickly clogged up when exposed to the weather. By arranging
that the bends are never too sharp, a series of letters can be made
without the necessity of brazing, except, perhaps, here and there,
to give an even supply. By remembering that curves can be left
undrilled if necessary, much can be done in this way, especially if
the uniting form of letters is adopted. Fig. 109 is an example of
this class of work. The designs shown by Figs. 110 and 111 are speci-
ally suitable for street illumination, while others are the Prince of
Wales' feathers, crosses, and stars of all patterns and of various
GAS-FITTING FOR FESTIVAL ILLUMINATIONS. HI
numbers of points, suitable dates composed of numerals, V.R.
nnd V.R.I, in all kinds of letters, from the plain block to the
most ornately flourished, with ornaments and portraits. These
last require more special care in order to catch the likeness,
and necessitate very expert bending and drilling.
Transparencies also provide a favourite form of illumination,
as they do not burn so much gas, and are nevetheless very
effective. They should be painted in oils on thin and even-
- ..... \ :..." ...... X.
:- X'"... \ : .-" -. .1
\ ........ ..... ................. J
Fi^. 111. Crown for Festival Illumination.
textured canvas, using only such colours as are transparent, and
avoiding most, if not all, of the earth colours. The canvas is
stretched upon a frame, and a sheet-iron band is fixed all round
this, to prevent the gas jets, which are placed behind, being seen
from the side, and so spoiling the effect of the transparency.
It is customary for gas-fitters who are likely to be fixing gas
illumination devices to give early notice to the gas companies of
the requirement of special services from the main.
142
CHAPTER X.
GAS FIRES AND STOVES FOR WARMING AND COOKING.
AN examination of the principles of gas stoves, and a consider-
ation of the advantages and disadvantages of these heating-