IMPROVED GAS METER
Year: 1830

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
CLEGG, of No. 16, Sidmouth Street, Gray's Inn Lane, in the County of
Middlesex, Engineer, send greeting..
WHEREAS I did, by Petition, humbly represent to His most Excellent
Majesty King William the Fourth, that I had invented an "IMPROVED GAS
METER," and His said Majesty, being willing to encourage all useful inventions,
was graciously pleased to issue His Royal Letters Patent under the Great Seal
of Great Britain, bearing date at Westminster, the Twentieth day of October,
One thousand eight hundred and thirty, and in the first year of His reign, by
which Letters Patent His said Majesty did, for Himself, His heirs and
successors, give and grant unto me, Samuel Clegg, my exors, adñiors, and
assigns, His especial licence that I, the said Samuel Clegg, my exors, adñors,
and assigns, and such others as I or they should agree with (and no others),
might lawfully make, use, exercise, and vend my said Invention within that
part of His Majesty's United Kingdom of Great Britain and Ireland called
England, His Dominion of Wales, and Town of Berwick-upon-Tweed, in such
manner as to me, the said Samuel Clegg, or my exors, admors, or assigns,
should seem meet, and should have and enjoy the whole profit, benefit,
commodity and advantage arising from the said Invention during the term of
fourteen years from the date of the said Letters Patent; in which said
Letters Patent there is contained. a proviso that I, the said Samuel Clegg,

page_text: should, within six calendar months from the date of the said Letters Patent,
cause a further description of the nature of my said Invention, and of the
manner in which the same is to be performed, by an instrument in writing
under my hand and seal, to be inrolled in His Majesty's High Court of
Chancery, as in and by the same (reference being thereunto had) will more
fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Samuel Clegg, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are described and ascertained
in manner herein-after set forth, and as represented in the Drawing hereunto
annexed:-
In order to shew more fully the novelty and utility of my said Invention,
I first premise that gas meters are machines which show (by indexes pointing
to numbers on dials in the manner of the hands of a clock) what number of
cubic feet of gas has passed through them, so that the proprictors of gas
establishments may take the account from time to time of the quantity of gas
they have manufactured or supplied to consumers; that the original gas
meter was invented by mo and forined part of a gas apparatus, for which His
late Majesty King George the Third granted me His Royal Letters Patent,
dated the Ninth December One thousand eight hundred and fifteen, and
which gas meter is described in my Specification dated the Eighth day of Juno
One thousand eight hundred and sixteen; that since that time gas meters
have been improved in their construction by me and by other persons, and
have been brought into very extensive use; that the gas meters now in uso
consist of a hollow wheel or drum, which is mounted on pivots so as to
be capable of revolving freely on its axis, and the interior capacity of the
hollow wheel is divided by partitions into chambers which are capable of
containing gas; that the said revolving wheel is enclosed within a box or case
containing water in its lower part, and the wheel is immersed higher than its
centre in the water, so that all those chambers which are at the lower half of
the wheel will be filled with water. The gas which is to be measured is
introduced by a supply pipe into the central part of the revolving wheel, and is
thence admitted by a suitable communication into one of the chambers in tho
lowest part of the wheel which is full of water, and which gas, by expelling the
water from the said chamber, causes the wheel to turn round progressively as
the gas fills the chamber; but when the chamber is so filled the aforesaid
communication between that chamber and the supply pipe is intercepted, and
a similar communication is opened from that pipo to the next succeeding
chamber in the lowest part of the wheel, which chamber is full of water, in

page_text: of
order that the said next chamber may be filled with gas in its turn. The
wheel is kept continually turning round by the aforesaid influx of gas from
the supply pipe into its several chambers one after another, that gas expelling
the water from those chambers, and as the wheel turns round its several
chambers which have been thus filled with gas must descend again into the
water in which the lower half of the revolving wheel is immersed, and that
water entering into the chambers displaces and empties the gas therefrom
through suitable communications into the upper part of the box or case in
which the revolving wheel is enclosed, and from whence the gas passes away
by a pipe to its place of destination for sale or for consumption. The quantity
gas I which so passes away in any given time is determined by the number
of chambers in the revolving wheel which have been filled with gas from the
supply pipe and emptied again into the box or case of the meter in the same
time, because the arrangements of the said chambers in the wheel, and of the
water out of which they ascend and into which they descend again, and also
the arrangements of the various communications from the supply pipe into the
said chambers, and from those chambers into the box or case of the meter,
are such as will ensure that each succeeding chamber shall be completely
filled with gas from the supply pipe before it begins to empty out that gas
again into the box or case, and also that the same chamber shall afterwards
be completely emptied of gas into the said box or case before it begins to fill
itself again from the supply pipe, therefore the number of chambers which
have been so filled and emptied in a given time becomes a measure of the
quantity of gas which has passed in that time. The number of turns which
the revolving wheel of the meter has made is counted, and the corresponding
quantities of gas which have passed through the meter are recorded by wheel-
work and revolving indexes, similar to those of a clock. And now I declare
that I do not claim as any part of my present Invention what I have above
set forth; but I declare that my improved gas meter does not work in water,
and hence it is not subject to the inconveniences and uncertainty of action
that may be occasioned by the waste of water from evaporation or other
causes in cases where gas meters do work in water; and my improved gas
meter operates without: that resistance to the passage of the gas through it
which has heretofore prevented the use of gas meters in situations where the
pressure of the gas in the main pipes has been very slight. The mode of
action in my improved gas meter is as follows:-The gas which is to be
measured is conducted by an entrance pipe from the place of supply into an
air-tight chamber, which I call the interior of the meter, and from thence the.
same gas is conveyed away by another pipe to the place of its destination or

page_text: consumption, so that all the gas which is to be measured must pass through
the said chamber. I apply heat by a flame of gas light at the outside of the
lower part of the meter or chamber, so as to warm the gas which is contained
in the interior, as soon as that gas which has entered from the supply pipe and
before it passes away by the exit pipe, and I place within the interior of the
meter a small instrument, similar to that commonly known by the name of, a
pulse glass or boiling glass, and which consists of two hollow glass globes
connected together by B glass tube bent into the form of the letter S.
These globes communicate freely by the bent tube, and their interior
capacity is partly filled with alcohol or other liquid which boils at a
low temperature, and the remaining part of that capacity is. left a void
space, from which the atmospheric air is exhausted and. kept excluded,
and consequently. that space will become filled with a rare vapour arising
from the alcohol, but. that vapour will be more or less rare,. according to the
temperature of the alcohol. This pulse glass is poised upon a horizontal axis
affixed to the bent tube in the line between the centres of the two globes, and at
half way between those centres, so that the two globes may balance each other
at opposite sides of the axis, and be capable of revolving freely upon the axis;
and by means of a catch (which detains a pin at the end of a lever fixed on
the said axis) one or other of the said globes is caused to stop immediately
opposite to the aperture of the spout at which the cold gas is conducted from
the supply pipe into the interior of the meter, and which is situated at the top
or upper part of that interior. As the pulse glass revolves upon its axis the two
globes are caused to stop by turns in that position. The heat arising from the
small flame. of gas, which is placed externally underneath the heter, is trans-
mitted to the gas contained in the interior of the meter by means of a solid
piece of copper (or other metal of quick conducting power) which passes from
the outside of the meter to the interior thereof, and thereby the temperature
of the gas within the meter is so much raised above the temperature of the
gas which is coming into the meter from the pipe of supply, that the elasticity
of the vapour arising from the alcohol contained in the globes of the pulse
glass (and filling the exhausted spaces within those globes), will be sensibly
increased beyond the elasticity that the same vapour will have when it is
cooled down again to the temperature of the stream of fresh gas which is
ontering from the pipe of supply into the meter through the spout at the
upper part thereof, and as the entering stream. of colder gas blows down upon
the upper globo of the pulse glass (which globe is detained by the catch
opposite to the entrance spout as aforesaid), the vapour which that upper
globe contains is cooled and partly condensed, so as to diminish its elasticity,

page_text: whilst the vapour contained in the lower globe, being surrounded by the warm
gas, retains its elasticity and forces up a small portion of the liquid alcohol
from the lower globe through the bent tube into the upper globe, the heat of
the surrounding gas causing more vapour to be formed in the lower globe as
fast as the alcohol passes out from it, and the cooling and condensing of the
vapour in the upper globe making room therein.for the alcohol, which is thus
transferred from the lower globe to the upper one, until by such transfer the
centre of gravity of the whole pulse glass becomes raised above the axis on
which it is poised; or, in other words, the pulse glass becomes top heavy, and
then turns over upon its axis, or oversets as soon as its balance is become
sufficiently deranged. In so turning over, the upper globe descends and
brings that which was the lower globe up opposite to the stream of colder gas
which is issuing from the spout of the supply pipe, and in that position the
pulse glass is detained by the aforesaid catch, which always allows the pulse
glass to turn round upon its axis in moving forwards, but the catch always
prevents it from moving backwards upon its axis. The cold stream of entering
gas blowing down upon that upper globle again cools and partly condenses the
vapour contained therein, whilst the vapour in the lower globe derives heat
and increased elasticity from the warm gas by which it is surrounded; a fresh
portion of the alcohol in the lower globo will consequently be forced up again
through the bent tube, and transferred into the upper globe until the pulse
glass is again rendered top heavy and caused to overset as before. . This
alternate action of the two globes, occasioned in manner aforesaid, and the
turning of the pulse glass upon its axis half a revolution every time, is con-
tinually kept up so long as the gas within the interior of the meter is kept
sufficiently heated, above the temperature of the gas which is entering in a
stream into that interior from the pipe of supply. The pulse glass will make
one of its alternations every time that a certain quantity of gas has entered
through the spout of the supply pipe into the interior of the meter, and has
blown down in a cold current upon that globe which is uppermost, therefore
the number of alternations that the pulse glass has made in any given time
becomes a measure of the quantity of gas which has flowed into the meter in
the same time. The revolving motion of the pulse glass is transmitted by a
suitable train of clock wheelwork to suitable indexes, which show on divided
dials the number of cubic feet of gas which has passed through the meter.
The said clockwork and dials must be constructed suitably to the quantity of
gas which, when the meter is first set to work, is found to pass through it at
each alternation of the pulse glass, and that adjustment being correctly made,
the meter will become a measure of gas in cubic feet. The pulse glass will

page_text: turn quicker or slower according as more or less gas is passed through the
meter, because the entering current of cool gas is blown with more or less
rapidity upon the upper globe, so as to condense its contained vapour
more or less rapidly; and, in order to counteract the effect of variation of
temperature in that stream of entering gas, the entrance pipe is made of
thin metal, in a flat form, so as to expose a considerable surface in proportion
to the passage through it, and a considerable length of that thin flat pipe is
coiled round within the interior of the meter, so as to be surrounded with the
warm gas contained in the interior of the meter, in order that the gas flowing
through the said coils of flat pipe may derive some heat from the said warm
gas before it arrives at the spout through which it is to blow in a current
upon the uppermost globe of the pulse glass, according to the greater or lesser
facility of this transfer of heat from the warm gas within the meter to the cool
stream of outering gas. The successive alternations of the pulse glass will
tako place at every interval when a greater or lesser quantity of cool gas has
been blown down upon its uppermost globe, because a certain relation is kept
up between the temperature of the warm gas contained in the meter and the
entering stream of coal gas, the latter being warmed and the former being
cooled by the transfer of heat through the thin metal of the coils of the entrance
pipe; and, for the same reason, inequalities of temperature from summer or
winter seasons, or from a greater or lesser flame of gas being burned beneath the
meter, will not make any sensible alteration in that incoming quantity of gas
which will produce each successive alternation of the pulse glass, and therefore
the indexes and clock wheelwork being originally constructed to correspond
exactly with that quantity of gas which is found to pass through the ineter
when it is first set to work, it will continue to measure gas correctly so long as
its parts continue in repair. The heat generated by the small flame of gas
which is kept burning externally beneath the case or chamber of the meter
is conducted directly up into the center of the meter by the copper conductor
before mentioned, and the heat of the flame is insulated from contact with the
metal of which the case or chamber of the meter is formed, and also from
contact with the entrance pipe through which the gas is conducted into the
meter. The outside of the case or chamber of the meter should be surrounded
by a suitable outer casing, or by a cloathing of slow conductory substance, to
prevent any material wasto of the heat by communication to the surrounding
air. In order that the gas may be prevented from passing through the
meter when no heat is applied externally by the flame of gas beneath it, or
only so little heat as will not be sufficient to keep the pulse glass in motion
and operation as aforesaid, a stop valve is fitted into the orifice of the exit

page_text: pipe, and that valve is suspended by a thermometric apparatus which operates
by the expansion of a combination of metallic bars, that expansion being
accumulated and multiplied by a series of levers, from one of which the valve
is suspended, so as to keep open the exit passage so long as the gas within the
meter continues to be at the proper temperature for the operation of the pulse
glass; but whenever the said gas becomes cooled below that temperature the
contraction and shortening of the combined bars will be transmitted by the
levers with a great multiplication of motion to the said stop valve, so as to let
And I, the
it down and stop the exit passage of the gas out of the meter.
said Samuel Clegg, do hereby declare that my present Invention consists
in that combination of parts herein before set forth, which, by the operating
in the manner herein-before set forth, doth constitute an improved gas
meter, and which combination of parts and mode of operation, as applied for
the purposes of a gas meter, I believe to be a new invention, although some of
the parts of the said combination may have been heretofore used for other
purposes. The arrangement and construction of the various parts of my
improved gas meter may be greatly varied and modified without deviating
from the essential properties of my Invention, as I have herein-before defined
the same; but to the end that competent mechanicians may be enabled by
this my Specification to construct my improved gas meters, I have hereunto
annexed a Drawing of one of my improved meters, which I have had in
use and found to answer the purpose of measuring gas with sufficient
precision for practical use in business.
REFERENCES TO THE DRAWINGS HEREUNTO ANNEXED.
Figure 1 is a vertical section of the meter viewed in front; Figure 2 is a
vertical transverse section; Figure 3 is an elevation of the meter with the
front plate removed; Figure 4 is a horizontal plan, and Figure 5 is an
elevation of the thermometric apparatus which opens and shuts the exit valve.
All the Figures are drawn to about half the size of an improved meter, which
will measure a sufficient quantity of gas to supply five lights of the kind called
Argand burners, each consuming about five cubic feet of gas per hour, and the
same letters of reference are used to denote the same parts in all the Figures.
A, A, are the two glass balls of the pulse glass. B, the brass socket by which
the crooked glass tube which joins the two balls A, A, is fixed to the hori-
zontal axis Y, Y, on which the whole pulse glass is poised, and about which
axis the balls A, A, move in a circular orbit. The brass socket B is made in
two halves, which are tied together about the glass tube by bands of soft wire.
C, C, is the metal frame in which the axis Y, Y, is supported, and within

page_text: which frame the pulse glass is contained, so as to be at liberty to revolve
about its axis. J, J, is the piece of copper or other metal beneath which the
flame of gas is burned at the lower part of the case of the meter in order to
give warmth to the gas contained within the interior capacity of the meter:
Qis the pipe which conveys the gas from the interior of the meter to supply
that flame. The heat occasioned by the flame is conducted upwards by the
piece of copper J, J, to the metal of the frame C, C, which is thereby kept
warmed, and it communicates heat to the gas contained within the meter, for
the metal, being surrounded by that gas, gives warmth thereto. N, N, is the
cylindrical box or case of the meter, containing the frame C, C, and the
revolving pulse glass within it. The front end of the case is closed by a
circular plate, screwed on by several small screws, the joint being made tight
by interposing pasteboard or other suitable packing with putty. The said
circular cover plate is made of double thickness to retain the heat. 0, 0, is
an outer casing surrounding the cylindrical box or casing N, N, of the meter
at every part, and making a double thickness of metal to the case of the
meter, and air being retained in the space between the two thicknesses it
prevents loss of heat from the gas within the meter to the external air.
T, Figures 1, 2, and 3, is the base on which the cylindrical box or case of the
meter is fixed. It stands on four balls for feet, and the burner Q is beneath.
it. A hole is made through the base T to admit the piece of copper J, J,
which conducts the beat of the flame upwards to the frame of metal C, C, in
order to warm the gas contained in the interior of the meter. In the
Plan, Figure 4, U is the entrance pipe for bringing the cold gas which
is to be measured by the meter from the place of supply to the meter;
that gas is introduced into the interior capacity N, N, of the meter at
the upper part thereof, through a spout k, so as to blow down in a cold
current upon the uppermost globe A of the pulse glass, in order to cool
the contents of that globe; and the measurement of the quantity of gas
takes place by blowing down and cooling the said globe, as before described;
but after being so measured the gas enters into the interior capacity
N, N, of the meter, and there it becomes warm by the heat transmitted
through the metal of the conductor J and of the frame C, C, from the
burning gaslight at Q. The cold unmeasured gas is conveyed from the pipe U
to the spout by a flattened tube I, I, made of very thin metal, which tube is
coiled round in a circular curve withinside of the interior circular case N, N,
so as to make a long channel of communication for the cold unmeasured gas
to pass through by a circuitous route during its passage from the end of the
pipe U to the entrance spout at k into the interior of the meter. The cold
k

page_text: unmeasured gas passing through the interior passage of the flattened pipe I, I,
absorbs some heat from the, warm measured gas contained within the interior
of the meter, which gas surrounds the outside of the flattened pipe, and an
absorbtion of heat will take place through the thin metal of which the flattened
tube I, I, is made, whenever there is any considerable difference of tem
perature between the temperature, of the warm measured gas contained in the
interior chamber N of the meter and the temperature of the cold unmeasured
gas coming to the meter from the pipe U. The flattened pipe I, I, is disposed
round the interior circle of the meter in three curved portions side by side,
videlicit, one of those curved portions is joined at its lower end to the end of
the entrance pipe U, and thence it extends nearly all round the circle, of the
interior of the meter at the back of the box (that is, at the side furthest from
its moveable cover); that first curved portion is then joined by a bend at
right angles, which passes horizontally across from the back to the front of the
box or interior of the meter: (that is, to the side thereof where the cover takes
off), then the bend joins to the second curved portion, which is exactly
similar to the first, and in like manner it extends round the circle of the
interior of the meter, but at the front of the box, instead of at the back
thereof; the end of the second curved portion tlien joins by a shorter bend at
right angles to the third covered portion, which proceeds around the same
curve as the first and second portions, but in the middle of the box; between
those two portions, until the upper end of the third portion (which is shorter
than the.other two) reaches over the uppermost globe of the pulse glass, and
there the spoutk is joined' to it to discharge the gas on that globe in a direc-
tion pointing towards the centre thereof. Y is the axis on which the pulse
glass revolves. It is supported in pivot holes in the sides of the metal
frame C, C, and at one end of the axis a pinion L is fixed to give motion
to a. train of counting or clock wheelwork, similar in construction to the
wheelwork in the meters now in common use, and which wheelwork must
be so proportioned as to indicate by suitable indexes on suitable divided
dials the quantity of gas which was passed through the meter in cubic
feet; for according to the number of revolutions that the pulse glass has
made in any given time, so will be the quantity of gas which has passed,
through the meter in that time; because in order to produce each alternation
of the pulse glass, a certain quantity of incoming gas must have been blown.
down upon its uppermost globe and have been passed through the meter, and
the wheelwork must be proportioned according to the actual trial, so as..to
indicate on the dials the true quantity in cubic fect; that is to say, if it is
found on trial of an improved meter when set to work for the first time that

page_text: its dials indicate a greater quantity of gas than is proved by another standard
meter, or by a gasholder or gasometer to have actually passed through the
improved meter, the pinion L must be changed for a smaller one, or else the
toothed clock wheel which is turned by that pinion must be changed for a
larger wheel, until a correct count is obtained, correspondent with the said
standard 'meter, or gasholder, or gasometer. The said meter may be inade
on the present improved plan, and accurately adjusted by a gasholder or
gasometer, otherwise it may be made on what is now the common plan,
derived from my former Invention of chambers in a revolving wheel balf
immersed in water, those chambers being filled and emptied alternately with
gas. V is the exit pipe from the meter to convey the measured gas to its
place of destination, or to the burners which are to be supplied with measured
gas. At the entrance of the pipo V is a stop valve M, which is made of ivory,
in form of a conical plug to drop into an orifice in a steel ring, so as to stop
the passage when the plug is let down, or to open it when the plug is lifted up,
by a thread or wire from the thermometric apparatus shewn in Figure 5.
W, in Figure 3, is a double-ended lever fixod on the axis Y; a pin Z is fixed
in each end of the lever; one of the pins Z rests against the end of tho
catch II, and by proventing the pulse glass from moving backwards, retains it
in the position shewn in Figure 1, with one of its globes in the direction of
the cold current of gas which is issuing from the spout K into the interior of
the meter. The same pin Z also rests beneath the lever G, the end of which
is bent out of the circle inwards, so that the lever G must be lifted up by the
pin Z before that pin can move forwards. The resistance occasioned to the
notion of the pin Z by so lifting the lover G, tends to prevent the pulse glass
moving forwards beyond its proper resting position by the motion it acquires
when it reverses, and it also detains the pulse glass from oversetting until
sufficient weight of the liquid alcohol is transferred from the lower globe to
the upper one.
Figure 5 is the thermometrical apparatus for opening and shutting the
exit valve or plug M. A flat plate of iron or steel ƒ is fixed to the frame C
at the outside thereof by 2 screws. D1 is a bar of zinc, which is a moro
expansible metal than that of which the plate f is composed; the lower end of
D1 bears upon a stud fixed to the plate f, and at its upper end it bears up the
short end of a lever h, which is moveable on a centro pin screwed into 'tho
plate, and the long end of the lever h bears down on the top end of another
bar of zinc D 2, the lower end of which rests on the short end of a second
lever k, which moves on a centre pin scrowed into the plate f, and the long
end of bears a third bar of zinc D 3, whoreof the upper end bears up the

page_text: short arm of a lever z, which is moveable about one of its ends on a centre'
pin screwed into the plate f, and the other end of the lever z suspends the
stop valve M by a wire loop. When the gas within the meter is maintained by
the heat of the flame burning at Q at a proper temperature for producing the
revolving motion of the pulse glass, the zinc bars D1, D2, D3, will bear
up the lever so much as to open the exit valve, and allow the warm
measured gas to go away from the meter to the burner, but by the contraction
of those bars in a greater degree than the plate f to which they are fitted,'
they will let down the lever and the valve M and stop the exit pipe
whenever the gas in the interior of the meter becomes cooled below the
proper temperature for producing the revolving motion of the pulse glass.
The operation of the improved meter is as follows:-Supposing a flame to be
lighted underneath the metallic conductor or piece of copper J at the lower
part of the meter, that flame consuming at the rate of about one fifth of a
cubic foot of gas in one hour, which is a sufficient quantity to give heat for a
five-light meter, or one which measures twenty-five cubic feet per hour,
therefore about one one hundred and twentieth part of the gas that is to be
measured will be consumed in the measurement. The flame must have been
lighted a sufficient time to beat the gas in the interior of the meter, and also
supposing that there is an abundant supply of cold gas coming from the supply
pipe U to be measured in passing through the meter. The cover which is
made double, or of two thicknesses, leaving a vacant space between them in
order to retain the heat which is communicated to the gas in the interior of
the meter, must be screwed to the flanch in the front of the meter with paste-
board or any other suitable substance interposed in the joint in order to make
it retain gas. The burners, which are to be supplied by the measured gas
which has passed through the meter, being lighted, the gas for the supply of
such burning must enter into the interior of the meter from the entrance
pipe U through the long flat pipe I, I, which makes three coils or fulds, each
fold nearly surrounding the interior of the circular vessel. In flowing through
that flat pipe, the incoming gas acquires a temperature which approaches
towards the temperature of the warm gas contained in the inner vessel N, N,
but nevertheless the gas always enters from the end of the flat pipe in a
current through the spout k into the interior of the meter at a lower
temperature than the gas within the meter, and that cold current blowing
directly down on the uppermost globe of the pulse glass cools and partly
condenses the vapour of alcohol within that globe, whilst, in consequence of the
other globe being kept warmer by being surrounded by the gas contained in
the meter, and an additional evolution of vapour will take place from the

page_text: alcohol contained in the lower globe, and that vapour will force up some liquid
alcohol from the lower globe through the bent tube into the upper globe as
fast as the condensation of the vapour contained in that globe will make
room for the said alcohol, and more vapour will continue to be generated from
the alcohol contained in the lower globe so long as that vapour can by its
clasticity drive up a portion of the liquid alcohol which it contains. This
transfer of alcohol.continues until the liquid so forced up into the upper globe
causes the upper globe to become decidedly heavier than the lower one, and
then the pulso glass oversets the upper globe descending and the lower one
ascending. By the sudden motion that the pulse glass acquires about its axis
when it so oversets it will take the heaviest globe considerably beyond its
lowest position, and then the pulse glass having made a half turn about its axis
is retained by the catch H which catches one of the pins Z, and prevents tho
glass moving backwards again, and at the next time when the upper globe is
again rendered the heaviest by liquid alcohol being forced up from the
lower globo by the generation of vapour therein as fast as the vapour in
the upper globe is condensed by the cold current of gas blowing upon it, so.
as to make room in the upper globe for alcohol to be so forced up, the
pulse glass will overset again and make another half turn about its axis
as before, and every such half turn will be registered by the counting
or clock wheelwork, and the indexes pointing to the numbers on the dial
thereof, will every time indicate an additional quantity of gas, such as has been
ascertained by trial to have passed through the meter at every time of the
pulse glass oversetting. The lever W being fastened to the same axis
y as the
pulse glass revolves with it, and at every half revolution which it makes one
or other of the pins Z, Z, at the ends of that lever come alternately in contact
with the catch H and lever G, both of which move freely on the same fixed
centre pin, but quite independently of each other. The catch II is prevented
from falling too low by tho stop a, and from being jerked up too high by the
stop at b. and when the pin Z on the lever W has passed beyond the end of
catch, that catch falls and prevents the pulse glass returning to the pin Z,
stopping against the end of the catch. The same pin Z also comes in contact
with the downward projecting part of the lever G, which lever is made of such
a weight that it will resist the motion of the pulse glass so much as to requiro
nearly all the alcohol to be discharged from the lower globe into the upper
globe before that resistance can be overcome, and then the glass will overset
suddenly. The other pin Z on the other end of the lever W answers the samo
purpose in its turn, for the pin Z at the end of the lever W lifts the catch II
and lever at one time of the pulse glass oversetting, and making half a

page_text: revolution, and the other pin Z does the same at the next succeeding time of
oversetting. The thermometric apparatus, Figure 5, which raises or lowers
the exit valve M, operates whenever the zinc rods D1, D2, D3, expand or
contract; and in order that the valve M may be lifted through more space
than the, zinc rods do actually elongate beyond the elongation of the iron
plate, to which they are fitted for this purpose, the centre pins of the
respective levers h and k, which transmit the expansion of one zinc, rod to the
next, videlicit, of D 1 to D2 and of D2 to D 3, are not placed in the middle of
the lengths of those levers, but the centre pins are nearer to the first zinc rod
in about the proportion of four to one, and the centre pin of the last lever is
placed at one end, in order to multiply the motion given to it by the zinc rod
D 3 in about the proportion of six to one. The conductor of heat or piece of
copper J is fitted tight to the inner cylindrical case of the meter by screwing
that copper into a socket which is formed at the lower part of the metal frame
C, C, in which the axis of the pulse glass is mounted, a millboard washer
being applied on each side of the metal case of the meter, and screwed up
tight by the shoulder of the screw on the piece of copper J, or any other sub-
stance which is a slow conductor of heat, and at the same time sufficiently
clastic to make a tight joint, may be used. If at each revolution of the pulse
glass the indexes of the dials do not register the true quantity of gas passing
through the improved meter, as determined by trial with a true standard meter
or a gasholder or gasometer as aforesaid, the rapidity of action in the pulse
glass in the improved meter can be regulated by altering the positions of the
three coils of flat pipes I, I, around the inner circumference of the meter, in
order that they may be placed so as to be more or less exposed to the heat
radiating from the inner metal frame C, C, which contains the revolving pulse
glass and supports its horizontal axis so that the current of gas which blows
down upon the uppermost globe, of the pulse glass may be rendered more
nearly of the same temperature as that of the warm gas within the interior of
the meter. By this means a slower or a quicker rate of action may be given
to the pulse glass, as may be required; but what that rate will be can only be
ascertained by trial, though, when once determined, it will not vary so long as
the flat pipe I, I, retain the same position within the interior case. The coils
of flat pipe I, I, which convey the gas immediately over the pulse glass, must
not come in contact with the frame C, C, in which the pulse glass revolves;
neither must the coils of pipes I, I, touch each other laterally except at the
bends at the end of each coil, by which they join one to the other. The base
T, T, on which the meter stands is made of metal with sides, in the form of a
tray. The upper surface of the base r, r, is of wood, with the metal plate at

page_text: the bottom of it. The wood does not come in contact with the lower part of
the base except in the middle, where it joins to the top of the inverted funnel,
through which the heat conductor J passes. The feet r, r, which support the
case of the meter from the base, are also made of wood inserted in sockets
soldered to the upper plate of the base, so as to avoid conducting any heat up
from the base to the case of the meter.
In witness whereof, I, the said Samuel Clegg, have hereunto set my
hand and seal, this Nineteenth day of April, One thousand eight
hundred and thirty-one.
SAMUEL (L.B.) CLEGG.
Signed, sealed, and delivered, by the
within-named Samuel Clegg, in the
presence of
H. ERNEST,
Clerk to Mr IT I Naild Sol