AN IMPROVED GAS METER
Year: 1824

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SIR
WILLIAM CONGREVE, of Cecil Street, Strand, in the County of Middlesex,
Baronet, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Fourteenth day of December, in the fifth year of His
reign, did, for Himself, His heirs and successors, give and grant unto me,
the said Sir William Congreve, His especial licence that I, the said Sir
William Congreve, my exors, admors, and assigns, should at any time agree
with, and no others, from time to time and at all times during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, my
Invention of "AN IMPROVED GAS METER;" in which said Letters Patent there
is contained a proviso obliging me, the said Sir William Congreve, by an
instrument in writing under my hand and seal, particularly to describe and
ascertain the nature of my said Invention, and in what manner the same is
to be performed, and to cause the same to be inrolled in His Majesty's High
Court of Chancery within six calendar months next and immediately after
the date of the said in part recited Letters Patent (as in and by the same)
referenco being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Sir William Congreve, do hereby declare that the nature of my said Inven-

page_text: tion, and the manner in which the same is to be performed, are particularly
described and ascertained in and by the following description thereof (that is
to say)
Instead of attempting to measure the gas itself that passes through the
aperture of the cock supplying any building (which from the subtil nature
of the gas, and from the small quantities as well as the trifling pressure
with which those quantities pass, has hitherto been found too nice an operation
to be at all exact), I measure merely the time that the cock through
which the gas passes is open, which, instead of being an operation of
any nicety, is in fact a very simple and common process, and yet it comes
exactly to the same thing; for as the pressure is always the same, and as
the aperture of the cock is also always a known quantity, it is evident that,
in the simple consideration of this problem, we have only to measure the time
that the aperture is open, in order to ascertain exactly the quantity of gas
delivered through this aperture in any given time. Pursuing the problem
therefore, in the first instance, in its simple form, the apparatus is as follows:-
Connected with the lever that opens the cock is a small watch movement with
a balance scapement worked by a spring, and which, when allowed to go,
would by a small dial indicate any number of hours of its motion, such as 100
or 500, or 1,000, as may be deemed most expedient. Now the process of
determining the quantity of gas admitted, is simply this, that when the cock is
shut, this watch or indicator, or register is stopped, while the mere act of
turning the handle of the cock, whenever the proprietor of the house wishes to
turn on the gas, allows the register to move; and the time of the passage of
the gas being thus indicated, the quantity that passes is known. It is true,
that if the cock is only half open the indicator will not be a true measure of
the quantity allowed to enter; but it is the fault of the person who takes the
supply, as it is by his own act that the cock is opened and the register set in
motion, if he does not take all that is allowed to him by obtaining the full
delivery of the aperture for which he pays. This is his affair, and is accord-
ingly placed in his power, while the just & equitable security sought for by the
meter is to prevent the possibility of the consumer taking gas at any time
without the knowledge of the person who supplies it, and against this tho
simple apparatus I have described effectually provides a check.
But it may
be said, that the meter thus far described is only applicable where the cock is
intended to supply one lamp in the building in which it is used. We have now,
therefore, to consider it in its more complicated applications, or where there are
many lamps to be supplied. There are, in fact, many ways of extending it to
any manner of lamps. The most simple of these modes, where there is a

page_text: plurality of lamps, would evidently be to have a register for each lamp, by
having the entrance pipe divided into as many small branches as there may be
lamps to feed with a register on each branch; in this case the application is
exactly the same as in that already described, and the owner will open one,
two, or three of these cocks, as he may wish to use one or more of his lamps.
The reckoning also in this case with the company that supplies the gas will
be as simple as in that above described at the end of any stated period;
.according to the time which the register is calculated to go, either one month,
. or two, or three, the inspector of the company will visit the register or
registers (the dial and movements of which will be so inclosed and secured that
no other person can have access to them), and he will then ascertain how many
.hours each lamp has been allowed to burn during the interval in question.
On this fair principle, that if the consumer, by not opening each cock to its full
extent, has not taken the full quantity to which he was entitled it is his own
fault; while, on the other hand, the full time which each cock has been open
during the said interval of time is indicated, so that the supplier can in no way
be defrauded. I have stated that these registers may be wound up so as to go
for 100 or 500 or even 1,000 hours, according to the construction of the
register; in this respect, therefore, the supplier would have a certain indication
of the time which the cock has been opened during the month or three months
or more for which the instrument was calculated, so as to regulate the visits
of his inspector. Thus a register to go for a hundred hours, would allow of
seven hours per night burning for one fortnight, five hundred hours would there-
.fore allow of seven hours per night for ten weeks, or, on an average, might be
taken as sufficient for one quarter of a year, and one thousand hours would give
the same allowance for half a year; there could therefore be no objection on the
score of the necessary frequency of the visits of the inspector; although in some
instances where than the allowed time of burning might be suspected, the
register might be always visited at the end of its period of going. Thus a
register of one thousand hours would be a complete security for six weeks,
though the lamps were to burn day & night, & so on. It might, however, be
objected, that to have a register for each lamp would be a great inconvenience;
and so it would if the number of lamps were considerable; but where, as in
theatres, altho' the number of lamps is very considerable, there are never less
than ten or twenty burning at the same time, the same aperture and register
would apply to ten or twenty lamps which, in common cases, would be applied
to one, allowing only for the difference in the size of the aperture. There is,
however, another mode of a more refined application of the same simple
principle by which one register may be made to indicate the consumption of

page_text: any number of lamps; and it is thus arranged: A graduated scale is applied
to shew the opening of the cock to a certain degree, one either to one or to
ten or to a hundred lights, while the act of turning the cover to open the cock
shall, by a connection of that lever with the balance spring, so regulate tho
rate of the going of the regulator that the number of hours indicated at the
end of any period shall shew the average delivery of the cock for that period,
supposing it to have been entirely instead of partially opened. Thus, if the
consumption of only one lamp out of four, or ten out of forty, is to be
indicated, the aperture formed by opening the cock in either of these cases,
due only to a consumption of one fourth, would only be one quarter what it
would be if the whole aperture were opened; for, by this arrangement of the
machine, the rate of going would, by slacking the balance spring, as in the
ordinary regulation of all watches, only be one quarter of the full rate. In
other words, the indicator of the register in four hours, with only one fourth the
aperture, would be read upon the dial as if it were one hour with the whole
aperture; but this would equally indicate the true quantity of gas that had
passed during the period elapsing from one inspection to the other. It remains
only to notice one or two precautions in the construction of the machine. The
stop of the watch or register must not be operated upon by the act of closing
the cock until the gas aperture is completely shut off.
Now it is very
important here to state that this circumstance renders the register a completo
protection against the carelessness of servants, who, by their negligence in the
ordinary mode of shutting off the gas, produce not only bad smells, but dangers
of explosions. The interest of the master who may thus, by the going of the
timepiece or register, be made to pay for many hours of full supply, when, in
fact, a mere escape of gas is taking place by the cock being only imperfectly
shut, will be a sufficient guarantee against such inattentions. On the other
hand, the stop must by construction be taken off the timekeeper even before
the opening of the cock commences, and by this precaution no fraudulent
introduction of gas whatever can take place, for by this means the proprietor
of the lamp cannot turn on the gas without setting the register in motion.
This is in fact the counterpart of his not being able to stop the register until
he has completely closed the aperture. It is scarcely necessary to state that
each lamp must be supplied with its own small cock as usual; this is merely
a register upon the service pipe. It is obvious that a register cock of this
description would be equally applicable to measure the delivery of water from
the mains of the water companies, and would be attended with great con-
venience to all parties. It would not only save the expence of tanks and
cisteins in houses or in the supply of steam engines, but would allow the public

page_text: a constant and unlimited supply from full mains, without putting the com-
panies to the trouble and expence of turning on and off, which operation is
invariably attended with very considerable waste, even with the greatest
vigilance on the part of the turncocks. To any one conversant in these
matters it is evident that the construction of such a register would not only be
very inexpensive but very simple and very durable, and would involve very
little trouble or attention in its application.
In witness whereof, I, the said Sir William Congreve, have hereunto
set my hand and seal, this Fourteenth day of June, in the year
of our Lord One thousand eight hundred and twenty-five.
WILLIAM (L.B.) CONGREVE.
AND BE IT REMEMBERED, that on the Fourteenth day of June, in
the year of our Lord 1825, the aforesaid Sir William Congreve came before
our said Lord the King in His Chancery, and acknowledged the Specification
5 aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Inrolled the Fourteenth day of June, in the year of our Lord One
thousand eight hundred and twenty-five.