CERTAIN PROCESSES, MEANS, OR METHODS OF HARDENING AND IMPROVING TALLOW AND OTHER ANIMAL FATS AND OILS, SO AS TO MANUFACTURE THEREWITH CANDLES OF A SUPERIOR QUALITY TO THOSE AT PRESENT MADE FROM TALLOW
Year: 1819

page_text: HEARD'S SPECIFICATION..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HEARD, of Brighton, in the County of Sussex, Chemist, send greeting.
WHEREAS His present Majesty King George the Third, in and by
His Letters Patent under the Great Seal of Great Britain and Ireland,
bearing date at Westminster, the Twelfth day of February now last past,
for Himself, His heirs and successors, did give and grant unto me, the
said Edward Heard, my. exors, admors, and assigns, His especial licence,
full power, sole privilege and authority, that I, the said Edward Heard,
my exors, adiñors, and assigns, and every of them, by myself and them-
selves, and by my and their deputy or deputies, servants, or agents, or such
others as I, the said Edward Heard, my exors, admors, or assigns, should at
any time agree with, and no others, from time to time and at all times there-
after, 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 "CERTAIN PROCESSES, MEANS, OR
METHODS OF HARDENING AND IMPROVING TALLOW AND OTHER ANIMAL FATS AND
OILS, SO AS TO MANUFACTURE THEREWITH CANDLES OF A SUPERIOR QUALITY TO
THOSE AT PRESENT MADE FROM TALLOW;" in which said Letters Patent there
is contained a proviso obliging me, the said Edward Heard, by an in-
strument 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 two calendar months next and immediately
1

page_text: after the date of the said recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully appear.
NOW KNOW YE, that in compliance. with the said proviso, I, the said
Edward Heard, do hereby describe and ascertain the nature of my said
Invention, and in what manner the same is to be performed, by the following
description thereof (that is to say):-
My processes or means are as follows:-The first operation is to render the
tallow or other animal fat or oil capable of sustaining a higher temperature
without melting. This may be effected by the addition of either nitric acid,
nitrous acid, or nitro-muriatic acid, which must be added to the tallow, fat, or
oil when in a melted state, in a certain proportion which I have found
necessary for that purpose, and on the quantity or qualities of these acids the
success of the process is founded, so far as regards the action of the acid or
acids to be employed. But as the tallow, fatty matters, or oils met with in
the market are not always precisely of the same quality, the proportion of acid
must be varied on that account, therefore the absolute or precise quantity of
acid cannot be determined as applicable under all possible circumstances that
may actually occur. The intelligent manufacturer will, however, find no
difficulty on that account on being informed that the quantity of nitric acid
required will vary from half a drachm by measure to three quarters of an
ounce by measure of nitric acid of a specific gravity of 1.500 to one pound
averdupois of the tallow, fatty matter, or oils. A quantity of nitric acid
within the limits above mentioned will be sufficient in all cases. Half à
- drachm by measure is the quantity I find to succeed best with tallow prepared
from kidney suet only. Common tallow, commonly called town tallow, may
require a drachm, and the more oily, fatty substances, or those of a weak con-
sistency, and the oils, will require more, according to the degree of their
weakness of consistency up to the quantity of three quarters of an ounce by
measure to a pound averdupois. If nitro-muriatic acid or nitrous acid be
used the quantities required will be more; and in summer, when fatty
substances are more oily or of a weaker consistency, a small [proportion
beyond what is above stated will become necessary for tallow and town
tallow above mentioned. The tallow or other fatty matter or oil must be
melted, and the acid added, and a gentle heat must be maintained for some
time if tallow or fatty matter be used, until it has acquired an orange yellow
tinge. When this has been accomplished, the tallow or fat thus altered by
the action of the acid must be subjected to a powerful press. By this means
an oily fluid becomes seperated. This operation may, however, be performed
before or after the above fatty or oily substances have been submitted to the

page_text: effect of the nitric, nitrous, or nitro-muriatic acid, but it is better done after, as
the oil in combination with the fat is operated upon by the acid. The tallow
or fat prepared in the above manner will have a yellow colour, of which it may
be deprived by mere exposure to light and air. If a weaker acid than what
has been stated above be employed, a larger quantity of it will be required,
and if a stronger acid be employed a less quantity of it will be required in
proportion. In a similar manner any mixture whatever containing nitric acid
in a free or uncombined state may be employed, because it is the action of the
nitric acid on which the effect depends. Although the effect may be produced
by nitric, nitrous, or nitro-muriatic acid, I find nitric acid, of specific gravity
1-500, and in the quantities I have stated, to succeed best. Nitrous acid and
nitro-muriatic acid will succeed, as they both contain nitric acid, but as the
quantity of nitric acid varies they are not so fit for the purpose.
Although I use pressure I do not claim any exclusive right to the operation
of pressing, which has been applied before to fatty matters for the purpose of
freeing them from oil, but to the application of nitric, nitrous, or nitro-
muriatic acid in the manner and in the quantities above stated, with which I
combine pressure either before or after my said application of the acid, and
which together produce a substance of a superior quality for the making of
candles.
In witness whereof, I, the said Edward Heard, have hereunto set my
hand and seal, the Eighth day of April. One thousand eight hundred