IMPROVEMENTS IN THE TREAT- MENT AND PREPARATION OF THE SUBSTANCE KNOWN AS 'GUM TRAGACANTH.”
Year: 1883

page_text: LETTERS PATENT to Alexander Campbell Duncan of Manchester in the
County of Lancaster. for an Invention of "IMPROVEMENTS IN THE TREAT-
MENT AND PREPARATION OF THE SUBSTANCE KNOWN AS 'GUM TRAGACANTH.”
PROVISIONAL SPECIFICATION left by the said Alexander Campbell Duncan
at the Office of the Commissioners of Patents on the 17th April 1883.
ALEXANDER CAMPBELL DUNCAN of Manchester in the County of Lancaster
"IMPROVEMENTS IN THE TREATMENT AND PREPARATION OF THE SUBSTANCE KNOWN
AS "GUM TRAGACANTH'
"
This invention consists in subjecting gum tragacanth to elevated temperatures in
hot air or in Petroleum spirit or oil, or in other oil or medium in which the said
gum tragacanth is not soluble.
The effect to be produced is to change the condition of the natural gum
tragacanth, by calcining roasting or frying, into one of greater solubility tenacity,
and permanence when dissolved in water, so as to render it more valuable and
more suitable for use in calico printing and other manufactures than it is in the
natural or raw state.
To effect these objects I dry the gum tragacanth slightly, grind it finely, and
subject it to roasting or calcining in hot air, or to boiling or frying in petroleum or
other oil or medium in which the gum tragacanth is not soluble.
When oil is used for this purpose it must be subsequently removed by pressure
and lixiviation.
The principal feature of novelty in the invention is the treatment or preparation
of gum tragacanth by calcining roasting or frying so as to change and improve its
condition and behaviour as a gum when used in calico printing and other
manufactures.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Campbell Duncan in the Great Seal Patent Office on the
17th October 1883.
ALEXANDER CAMPBELL DUNCAN of Manchester in the County of Lancaster
"IMPROVEMENTS IN THE TREATMENT AND PREPARATION OF THE SUBSTANCE
KNOWN AS "GUM TRAGACANTH "
This invention consists in subjecting gum tragacanth to elevated temperatures
in hot air or in petroleum spirit or oil, or in other oil or medium in which the said
gum tragacanth is not soluble. The effect to be produced is to change the
condition of the natural gun tragacanth by calcining roasting, or frying, into one
of greater solubility tenacity and permanence when dissolved in water, so as to
render it more valuable and more suitable for use in calico printing and other
manufactures than it is in the natural or raw state.
To effect these objects I dry the gum tragacanth slightly, grind it finely, and
subject it to roasting or calcining in hot air or to boiling or frying in petroleum or
other oil or medium in which the gum tragacanth is not soluble.
For calcining or roasting the gum I either place it in tubes or cylinders revolving
in heated air or on shelves in an oven, the temperature should be regulated
according to the effect or degree of calcination required the duration of the process
will also vary with circumstances it being necessary to give sufficient time for the
heat to penetrate and act on the particles throughout equally.
Hence the fineness of pulverization of the gum is of great importance.
For frying in petroleum oil or spirit I put the gum to be fried in a closed iron
vessel, capable of resisting the needful pressure (of say thirty pounds per square
inch) I then add the oil or spirit till it covers the gum and apply heat (preferably
from high pressure steam) until the oil or spirit boils thoroughly and the frying is
complete then the oil or spirit is to be drawn off and the gum dried.
When oil is used for this purpose it must be subsequently removed from the gum
by pressure and lixiviation
Having now described the nature and object of my said Invention together with
the manner in which the same is to be or may be performed or carried into
practical Effect I wish it to be understood that I claim as my invention.
The treatment or preparation of gum tragacanth by calcining roasting or frying
substantially as hereinbefore described so as to change and improve its condition
and behavior as a gum when used in calico printing and other manufactures.
In witness whereof I the said Alexander Campbell Duncan have hereunto set
my hand and seal this sixteenth day of October in the year of our Lord one
thousand eight hundred and eighty three.
ATVRDINGLY