AN IMPROVEMENT OR IMPROVEMENTS IN THE PROCESS OR PROCESSES OP PURIFYING A CERTAIN SPIRIT OR ESSENTIAL OIL, WHICH IS KNOWN BY THE NAME OF SPIRIT OF TAR, OR OIL OF TAR, AND WHICH IS OBTAINED FROM DIFFERENT LIGNEOUS, CARBONACEOUS, OR BITUMINOUS SUBSTANCES, BY MEANS OF WHICH IMPROVEMENT OR IMPROVEMENTS THE SAID OIL OR SPIRIT WILL BE SEPARATED FROM CERTAIN IMPURITIES WHICH HAVE HITHERTO PREVENTED THE APPLICATION OF SUCH OIL OR SPIRIT TO DIVERS USEFUL PURPOSES
Year: 1818

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir THOMAS
COCHRANE, Knight, commonly called Lord Cochrane, send greeting.
WHEREAS His present most Excellent Majesty King George the Third
did, by His Royal Letters Patent under the Great Seal of the United
Kingdom of Great Britain and Ireland, bearing date at Westminster, the
Third day of February, in the fifty-eighth year of His reign, give and grant
unto me, the said Sir Thomas Cochrane, commonly called Lord Cochrane,
my executors, administrators, and assigns, His especial licence, full power,
sole privilege and authority, that I, the said Sir Thomas Cochrane, commonly
called Lord Cochrane, my executors, administrators, and assigns, during the
term of years therein expressed, should and lawfully might make, use, exercise,
and vend "AN IMPROVEMENT OR IMPROVEMENTS IN THE PROCESS OR PROCESSES
OP PURIFYING A CERTAIN SPIRIT OR ESSENTIAL OIL, WHICH IS KNOWN BY THE
NAME OF SPIRIT OF TAR, OR OIL OF TAR, AND WHICH IS OBTAINED FROM DIFFERENT
LIGNEOUS, CARBONACEOUS, OR BITUMINOUS SUBSTANCES, BY MEANS OF WHICH
IMPROVEMENT OR IMPROVEMENTS THE SAID OIL OR SPIRIT WILL BE SEPARATED
FROM CERTAIN IMPURITIES WHICH HAVE HITHERTO PREVENTED THE APPLICATION
OF SUCH OIL OR SPIRIT TO DIVERS USEFUL PURPOSES," within England, Wales,
and the Town of Berwick-upon-Tweed, in such manner as to me, the said
Sir Thomas Cochrane, commonly called Lord Cochrane, my executors, admi-
nistrators, and assigns, should in our discretion seem meet; in which said
Letters Patent is contained a proviso that if I, the said Sir Thomas
Cochrane, commonly called Lord Cochrane, my executors, administrators,
and assigns, should not particularly describe and ascertain the nature of my
said improvements, and in what manner the same are to be performed, by

page_text: an instrument in writing under my hand and seal, and 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 Letters Patent, that then
the said Letters Patent, and all liberties and advantages whatsoever thereby
granted, should utterly cease, determine, and become void, as in and by the
said recited Letters Patent, relation being thereunto had, may more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Sir Thomas Cochrane, commonly called Lord Cochrane, do hereby declare
that the nature of my said improvements, and the manner in which the same
are performed, are particularly described and ascertained in manner following,
that is to say-
My improvement or improvements in the process or processes of purifying
a certain spirit or essential oil, which is known by the name of spirit of tar
or oil of tar, and which is obtained from different ligneous substances or
vegetable tars, and from different carbonaceous or bituminous substances or
mineral tars, consist in neutralizing, removing or subduing the acid contained
in the essential oil or spirit of the vegetable tar, and in neutralizing, removing,
or subduing the ammonia contained in the essential oil or spirit of the mineral
tar, and in separating and precipitating from the said oils or spirits respectively
those feculent, glutinous, or other gross particles which have heretofore pre-
vented the said oils or spirits from being conveniently applicable to the purpose
of producing light and affording illumination; and the manner and means of
performing the same are as follow:-
I mix the acid water or liquid derived from the vegetable tar with
the spirit or essential oil of the mineral tar for the purpose of neutralising
the ammonia contained therein, and I mix the ammoniacal water or liquid
derived from the mineral tar with the spirit or essential oil of the vegetable
tar, in order to neutralize the acid therein contained. The above acid and
ammoniacal waters or liquids are produced and obtained in the common
processes of making and boiling down vegetable and mineral tars respectively,
and in distilling their respective oils. The said acids and ammoniacal waters
or liquids so to be mixed with the said respective oils or spirits I dilute with
common water, and use them of such strength and in such quantity as to
neutralize the opposite quality of the oil or spirit on which the operation is a
performed, the arrival at which state of neutralization may be discovered by
means of the tests used to ascertain the prence of acid or ammonia. And I
agitate the mixture composed of the diluted liquid which I denominate the
neutralizing liquid, and the essential oil or spirit, at about the temperature of

page_text: 180 degrees of Fahrenheit, by means of a churn or similar device, in order
that every particle contained in the spirit or cssential oil may, as far as possible,
come in contact with the neutralizing liquid, so that the acid or ammoniacal
property or principle which retains the feculent, glutinous, or other gross
particles in union with the spirit or essential oil may be destroyed or subdued.
The neutralizing liquid, mixed and agitated as aforesaid with the spirit or
essential oil, ought to be at least equal in quantity to the spirit or oil with
which it is mixed; but I prefer that it should be greater, and that the
operation should be repeated until it ceases to. produce any further separation
of gross or impure particles from the said oil or spirit. By the above means
the essential oils or spirits of the vegetable and mineral tar, even the purest
now known in commerce, will be so far further purified, and so completely or
sufficiently divested of their acid and alkaline properties respectively, as to
be conveniently applicable to the purposes of producing light and affording
illumination each by itself separately and together, and by admixture with
other oils or inflammable substances. The acid and alkaline waters of
distillation or rectification of the said respective essential oils or spirits in the
common process may be also used in like manner and for the same purposes
as the above-mentioned neutralizing liquids, and other acid and ammoniacal or
alkaline solutions may be used, such as the pyroligneous acid, the sulphuric
acid, the muriatic acid, or common vinegar, for the mineral tar oil, and
ammonia, potash, kelp, barilla, or soda, for the vegetable tar oil. If the
essential oil or spirit of the vegetable tar is mixed with the essential oil or
spirit of the mineral tar in quantities proportioned to the acid and ammonia
which they respectively contain, the said acid and ammonia will neutralize each
other, and by adding to such mixture an equal or somewhat greater quantity
of common water, and agitating the whole in the manner and at or about the
temperature before described, the feculent, glutinous, or other gross particles
will be separated and precipitated, and the combined essential oils or spirits
of the two tars will be sufficiently pure for the purposes of producing light and
affording illumination with and without admixture with other oils or inflam-
mable substances.
Another more simple but loss complete and approved method of sub-
duing the acid and ammonia, and of purifying the spirits or essential oils of
the said vegetable and mineral tars, for purposes of illumination, is, by agitating
the same respectively with common water only, which will in a great degree
attenuate and dilute the acid and ammonia respectively contained in the said
essential oils or spirits, and will purify the said oils or spirits in such a degree
from the feculent, glutinous, or other gross particles remaining therein after

page_text: the common processes of purification as to rendler them conveniently appli-
cable to the purposes aforesaid. In this case the quantity of water required
to be mixed and agitated with the essential oil or spirit will be greater than
in the preceding cases, and the operation of agitating the mixture must be
continued or repeated until the acid or ammonia is sufficiently attenuated and
dilufed, and the feculent, glutinous, or other gross particles are separated.
In this and in the preceding cases I prefer that the water should first be boiled
and afterwards agitated with the oil at or about the temperature before
described. The essential oil or spirit of vegetable and mineral tar will be
more completely divested of their acid and ammonia respectively by agitation
with 'the neutralizing liquid than by plain water only, and better adapted for
'admixture with common oils for purpose of illumination. The essential oil or
spirit of vegetable and mineral tar, to be purified by any of the methods above
described, 'is that which has previously experienced the 'common process or
processes of purification; and the best rectified spirit or essential oil of either
vegetable or mineral far that can be procured may, by any of the above methods;
be so far further purified as to become conveniently applicable to the purposes
of producing light and affording illumination, separately, and by admixture
with other oils or inflammable substances, for which purposes I-claim all my
said methods of purifying the said essential oils or spirits, and all the modifica
tions of those inethiods whereby such purification may be effected by acids,
ammonia, alkali, or diluents being. .the agents and means aforesaid. But
whereas it is preferable to obtain the spirit or essential oil at once in a suffi-
ciently pure state for the purposes aforesaid, without repeated distillation or
rectification in vessels in contact with fire, be it known that my most approved
method of treating the gross extract of ligneous, carbonaceous, or bituminous
substances called spirit of tar or oil of tar, and separating the true spirit from
the impurities, colisists in evaporating the spirituous 'or oleaginous particles by
contact with steam, and is performed in the following manner-Let A be a
boiler heated by fire in any of the most convenient and effectual modes
whereby steam can be generated from water; let B be a pipe, which may
(and which I prefer should) terminate under a flat plate Z, on the surface of
the gross extract which is placed in the evaporating vessel C, to which 'I annex
"another for more vessels D, -D (of any convenient form), in which the tèni-
'perature of the vapour arising from C being lowered, the gross. and feculant
particles which require most heat to retain them in a state of vapour, and
which rise in distillation to a certain degree, even by the heat of steam, are
'deposited. And for the better ensuring such depósition I prefer to cause the
pipe or pipes, b,' to emit the vapour on the surface of water: imprégnated

page_text: with acid or aminonia (or alkali) according as the extract consists of mineral
or vegetable tar, or even plain water, in D, D, near which I retain it as before
by flat or concave plates Z, Z, surrounding the tubes b, b, and I regulate the
height of the said acid, ammoniacal, or neutralizing liquid or water, and
condensed vapour, by means of cocks, apertures, or. pipes F, F, proceeding
from the vessels C, D, D, for it is disadvantageous to plunge the extremity or
extremities of the pipe or pipes B, b, b, into the essential oil or spirit in C,
and into the neutralizing liquid or water contained in D, D, because of
the increased temperature thereby occasioned in the boiler A, and in the
evaporating vessel Cand vessels D, D, unless the atmospheric pressure shall
be taken off the orifices. of 'B, b, b, in a degree 'equivalent at least to the
resistance of the fluids in C, D; D; but in that case the said pipes may be
plunged into the essential oil or spirit and into the neutralizing liquid or water.
When the gross extract of ligneous, carbonaceous, or bituminous substances
aforesaid, known by the name of spirit of tar or oil of tar, is warmed for the
purpose of evaporating the spirituous from the gross particles thereof, and
when the gross particles, having their temperature diminished or lowered as
aforesaid, quit the spirituous and more volatile vapour, the said vapour, being
afterwards condensed in a worm or any convenient device G, G, flows from
the condenser in a pure liquid stream, together with condensed steam or
water (arising from the boiler A), upon the surface of which water it floats in
the vessel. E, in. which it is ultimately received, and is in a state of sufficient
purity. to be conveniently applicable to the purposes of producing light and
affording illumination. ..But nevertheless it is beneficial to agitate the spirit
or. essential oil so purified by steam with the mixture before denominated the
neutralizing liquid (or water impregnated. with acid or ammonia, according as
the spirit or oil is derived from vegetable. or mineral tar), or with plain water
only, that is to say, when the neutralizing liquid has been used in the process
by steam, the essential oil or spirit may afterwards be beneficially agitated with
plain water, but when plain water only has been used in the process by steam
the essential or spirit should be afterwards agitated with the neutralizing liquid,
except when the gross extracts of vegetable and mineral tars are mixed for
the purpose of being' purified by steam, in which case the acid and ammonia
will neutralize each other, and therefore plain water only ought to be used
both in the purification by steam and in the subsequent process of agitation.
In all cases it is advantageous that the agitation should be performed in the
manner already described, and I prefer that the water should first be boiled
and afterwards cooled down to the temperature before mentioned.
And whereas the feculent, glutinous, or other gross particles which are retained

page_text: in union with the spirit or essential oil known by the name of spirit of tar or
oil of tar, even after the common process or processes of purification, have here-
tofore prevented the said essential oil or spirit from being conveniently appli-
cable to the purpose of producing light and affording illumination (except in
tar works, or places where the offensive fumes produced by the imperfect com-
bustion of such oil or spirit are no material inconvenience, and where only a
dull, smoky, and torch-like flame is required), I claim my improvement or
improvements herein set forth in the process or processes of purifying the said
spirit or essential oil, and the modifications thereof, whereby the said spirit or
essential oil (which, when so purified, I denominate portable spirit of gas,) is
by itself, or by any mixture with other spirits, oils, or inflammable substances,
rendered conveniently or generally applicable to all purposes of producing light
and affording illumination, as a succedaneum for common oils or gas.
In witness whereof, I, the said Sir Thomas Cochrane, commonly called
Lord Cochrane, have hereunto set my hand and seal, this Eighteenth
day of June, in the year of our Lord One thousand eight hundred and