CERTAIN MEANS OF OBTAINING INFLAM- MABLE GAS FROM PIT COAL IN SUCH A STATE THAT IT MAY BE BURNED WITHOUT PRODUCING ANY OFFENSIVE SMELL
Year: 1806

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HEARD, of London, Chemist, do send greeting.
WHEREAS His most Excellent Majesty King George the Third, by His
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twelfth day of June,
in the forty-sixth year of His reign, did give and grant unto me, the said
Edward Heard, my executors, administrators, and assigns, His special license,
full power, sole priviledge and authority, that I, the said Edward Heard, my
executors, administrators, and assigns, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention or discovery of "CERTAIN MEANS OF OBTAINING INFLAM-
MABLE GAS FROM PIT COAL IN SUCH A STATE THAT IT MAY BE BURNED WITHOUT
PRODUCING ANY OFFENSIVE SMELL;" in which Letters Patent there is contained
a proviso, obliging me, the said Edward Heard, under my hand and seal, to
cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, 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
(relation being thereunto had) will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso in the said
Letters Patent contained, I, the said Edward Heard, do hereby declare that

page_text: my said Invention is fully described and ascertained as follows, that is to
say:-
I stratify limo with the coals in the retort, stove, or other close vessel in
which they are placed for operation, or suffer the gas when produced to pass
over lime previously laid in an iron or other tube, or any other shaped vessel
adapted for the purpose, and exposo it to the heat. After the gas has been con-
ducted into a refrigeratory, and all condensible matter is deposited, it is then
suffered to enter the conveying tubes, and burned in the usual manner. My
reason for employing lime for this purpose is, that from a series of analytical
experiments I have.detected the presence of sulphur in a great variety of the
coals which are consumed in this country, and as I consider the suffocating
offensivo smell so perceptible during the combustion of the gas obtained in
the ordinary way to arise from the products of that combustion, principally
the sulphureous acid gas which is. then generated. I present lime in substance
to the sulphur as it is disengaged by heat from the coals, and through their
mutual affinity arrest it in its progress, and form a sulphuret of lime or
hydrosulphuret, depending on the circumstances of the operation. I
reason to conclude that any of the fixed alkalies or alkaline earths, such as
barytes, strontian, and other similar earths, or carbonate of lime, when exposed
to a degree of temperature sufficient to drive off the carbonic acid gas, might
be substituted for lime, but from economical motives, as well as constant
success, I prefer the agency of lime. It must, therefore, be clearly understood
that lime in substance or a dry state, the fixed alkalics or carths possessing
alkaline properties, or such metals, or their oxides, as possess a sufficiently
strong affinity with sulphur and sulphurated hydrogen as to answer the end
desired, such as iron, manganese; zinc, copper, lead, &c. when mixed with
the coals laid on their surface, or put into separate vessels, through which the
gas is made to pass, are calculated in a greater or less degree to divest the
gas of the cause of the offensive smell; but I distinctly state that I have
always found lime (if caustic the better) stratified with coals and exposed to
heat the most economical and successful process.
In witness whereof, I, the said Edward Heard, havo hereunto set my
hand and seal, this Twenty-fifth day of November, in the year of our
Lord One thousand eight hundred and six.
havo

page_text: AND BE IT REMEMBERED, that on the Twenty-fifth day of November,
in the forty-seventh year of the reign of His Majesty King George the Third,
the said Edward Heard came before our said Lord the King in His Chan-
cery, and acknowledged the instrument aforesaid, and all and every thing
therein contained and specified, in form above written. And also the
instrument aforesaid was stamped according to the tenor of the Statute
made in the forty-fourth year of His said Majesty's reign.
Inrolled the Twelfth day of December, One thousand eight hundred and
six.