AN IMPROVE- MENT IN THE PREPARATION, FOR VARIOUS USEFUL PURPOSES, OF PITCH AND OF TAB, SEPARATELY OR IN UNION, BY AN ADMIXTURE OF OTHER INGREDIENTS WITH EITHER OR BOTH OF THEM
Year: 1823

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
HANCOCK, of Goswell Mews, in the Parish of Saint Luke, Old Street, in the
County of Middlesex, Patent Cork Manufacturer, send greeting.
WHEREAS His present Majesty King George the Fourth, by His Letters
Patent under the Great Seal of Great Britain, bearing date at Westminster
the Twenty-second day of March now last past, did give and grant unto me,
the said Thomas Hancock, His especial licence, full power, sole privilege and
authority, that I, the said Thomas Hancock, my executors, administrators, and
assigns, and such others as I, the said Thomas Hancock, my executors, admi-
nistrators, or assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term of years thercin expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, and also in all His said
Majesty's Colonies and Plantations abroad, my Invention of "AN IMPROVE-
MENT IN THE PREPARATION, FOR VARIOUS USEFUL PURPOSES, OF PITCH AND OF TAB,
SEPARATELY OR IN UNION, BY AN ADMIXTURE OF OTHER INGREDIENTS WITH
EITHER OR BOTH OF THEM;" in which said Letters Patent there is contained a
proviso obliging me, the said Thomas Hancock, 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

page_text: to cause the same to be inrolled in His said Majesty's High Court of
Chancery within six calendar months next and immediately after the date
of the said recited Letters Patent, as in and by the said recited Letters
Patent, reference being thereunto had, will more fully appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Hancock, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are particularly
described and ascertained by the following description thereof; that is to say :-
My Invention consists in the mixing caoutchouc and its solvent with pitch
or tar, or with pitch and tar combined together in various proportions, and
thereby rendering these substances, namely pitch and tar, whether separately
or in combination with each other, less soluble in water, tougher, more elastic,
and more durable than pitch or tar, or pitch and tar mixed together, and used
in their natural state, are found to be. Previously to describing my method of
preparing the solution of caoutchouc, &c., it is necessary for me to state that
caoutchouc is the substance which is more generally known by the names
elastic gum and indian rubber. Many, if not all of the essential oils will
dissolve the indian rubber; but for the sake of cheapness I prefer and therefore
employ the essential oil of turpentine or the essential oil of tar, either of
which is a good solvent of the indian rubber. I make the solution by first
cutting the indian rubber into very thin slips in order to increase the quantity
of surface of the said rubber, and thereby to expedite its solution when it is im-
mersed in the essential oil, and I immerse it in the said essential oil either in a
warm or cold state, and occasionally stir it until the solution of the indian rubber
is effected. I find by experience that the solution is effected in a shorter time
by exposing the essential oil and india rubber to a moderate degree of heat,
that is, not exceeding 180 degrees of Fahrenheit's thermometer. To make a
solution of indian rubber of about the consistence of tar, when at a temperature
of 60 degrees, I put about one pound of the indian rubber into one gallon of
the essential oil of turpentine. I mention this only by way of example, and
not as the definite proportions which uniformly adhere to, for I vary these
according to the nature and value of the object to which the composition is to
be applied. If the composition is to be made of pitch and a solution of
indian rubber, I mix them together by submitting them to such a degree of
heat as is just sufficient to melt and keep the pitch in a fluid state, and by
stirring it until the union is complete. Tar, so long as it is sufficiently fluid
(and it generally is so except in very cold weather) mixes very well with the
solution of indian rubber without being heated. In making a composition of
both pitch and tar, and the solution of indian rubber, I first melt the pitch and

page_text: mix it with tar in the required proportion, and then add the solution of indian
rubber. In preparing a compound to be applied to wooden buildings or
wooden fences, &c., by paying or smearing the same therewith, I have found
the following proportions to answer very well, namely, to one gallon of the
essential oil I put one pound and a half of indian rubber, mixing with it eight
or nine pounds of tar. If the compound is to be employed in making ropes,
or for covering canvas, &c., I use a solution of one pound and a half of indian
rubber in one gallon of essential oil, mixing with it about one pound of pitch
and six or seven pounds of tar. If the compound is to be used in paying the
bottoms of ships, or to be employed in preparing sheathing for ships, or paper,
or other substances for covering the bottoms of ships, or the roofs of houses or
other buildings, I dissolve three pounds of indian rubber in one gallon of essen-
tial oil, and mix it with six pounds of pitch. And lastly, with regard to the
proportions or relative quantities of the materials to be employed, namely, of
the essential oil of the caoutchouc or indian rubber, of the pitch, of the tar, or
of pitch and tar mixed as have hercin-before been described, it is evident
that such proportions or quantities may be infinitely varied at the discretion of
the operator; and I have only to remark, that in making any of the compounds
herein-before mentioned, that the elasticity, toughness, and durability of such
compound will be increased by increasing the quantity of indian rubber. I
would bere also observe, that I prefer making use of the best Stockholm tar
and Stockholm pitch. Any of the herein-before mentioned compounds, when
sufficiently thin and fluid, may be laid on cold with a brush; those which are
thicker require to be moderately warmed, so as to produce the required fluidity;
they may then be spread upon wood, paper, canvas, &c. with a brush or
trowel, or by any other of the well known methods for spreading or laying on
compositions of a similar nature. In using the trowel, or any other instru-
ment of a similar kind, to spread the composition, I occasionally dip it in
water to prevent the adhesion of the composition to the trowel or instrument.
The composition, when employed in making ropes, is applied in the same
manner as is commonly practised in making tarred ropes. In all the before-
mentioned processes I take care to avoid exposing the composition to a greater
degree of heat than about 180 degrees of Fahrenheit's thermometer. Lastly,
I do declare, that although I have herein-before described the method I employ
for making a solution of caoutchouc or indian rubber in essential oil of turpen-
tine, or in other essential oil, I lay no claim to the method of making such
solution as forming any part of my Invention, the same having been hereto-
fore known and used, but that my Invention consists in the admixture of
caoutchouc and its solvent with tar or with pitch, or with both tar and pitch,

page_text: so as to form a compound possessing the properties of being less soluble in
water, of being more tough, of being more elastic, and of being more durable
when exposed in the open air or under water than tar or pitch, or any mixture
of tar and pitch (without the aforesaid admixture) possess when similarly
exposed.
In witness whereof, I, the said Thomas Hancock, have hereunto set my
hand and seal, the Seventeenth day of September, in the year of our
Lord One thousand eight hundred and twenty-three.