IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF TAR OIL, FOR DISSOLVING INDIA-RUBBER, GUTTA PERCHA, GUMS, AND. GUM RESINS, AND ALSO IN DEODORIZING ALL FABRICS, WOOD, OR ANY ARTICLE IMPREGNATED WITH TAR OIL, OR THE PRODUCTS FROM COAL TAR
Year: 1856

page_text: PROVISIONAL SPECIFICATION left by John Metcalf at the Office of the
Commissioners of Patents, with his Petition, on the 3rd September
1856.
I, JOHN METCALF, of Newton Heath, near Manchester, in the County of
Lancaster, Manufacturing Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF TAR
OIL, FOR DISSOLVING INDIA-RUBBER, GUTTA PERCHA, GUMS, AND. GUM RESINS, AND
ALSO IN DEODORIZING ALL FABRICS, WOOD, OR ANY ARTICLE IMPREGNATED WITH
TAR OIL, OR THE PRODUCTS FROM COAL TAR," to be as follows:-
I manufacture, chloride of tar oil from the dead oil, crude oil, creosote, or
heavy oil of tar obtained from coal tar by distillation, which dead oil, crude oil,
&c., have hitherto been chiefly used for steeping railway sleepers, to preserve
them from decay; and I so purify, rectify, and redistil the said tar oil as to
render it fit and equal to naptha for dissolving india-rubber, gutta percha, gums,
and gum resins, and render it of far greater value than it has hitherto been.
I take the before-named heavy oil, dead oil, crude oil, or creosote, by all of
which names it is generally known, and in this said oil I mix any acid, neutral

page_text: salt, and alkalies, in proportions to be hereafter named. The acid alkalies
and neutral salt which I prefer to use (on account of cheapness) are sulphuric
acid, common salt, and caustic soda and lime. To every gallon of the before-
named oil I add about two pounds weight of rectified commercial sulphuric
acid, and half a pound of chloride of soda or common salt; I agitate this
mixture so as to thorourgly incorporate or mix it, which will take from three
to six hours, according to the speed given to the agitator. After this mixing
I let the whole settle for about twenty-four hours, or longer, if found necessary;
the longer it is allowed to settle the more of the clear liquor will be obtained;
when it is so settled there will be found a copious thick black precipitate. I
perform the said mixing in a tank, cistern, or cask, and draw off the oil with
syphons or taps, placed one above another, in such a manner that the whole
of the oil can be taken off without disturbing the thick pulpy precipitate.
I then take this oil and put it into a tank, cistern, or cask, or any convenient
vessel, and mix amongst it a sufficient quantity of caustic soda and lime,
which will neutralize any acid that is combined with the oil. I then separate
the caustic soda and lime from the oil, and put the oil so separated into a
common tar still, and distil in the usual manner until two-thirds of the whole
has distilled over; it will then be found to have acquired the property of
dissolving india-rubber, gutta percha, gums, or gum resins, with certainty and
expedition. To render it still more limpid and pure, I put the last-named
distillate through the whole of the above-named operations once or twice
more, according to the degree of purity I desire to arrive at, the more pure
it is the quicker it will dissolve the materials. I deodorize all kinds of fabrics
that are impregnated with the before-named india-rubber, &c., dissolved in
oil or naptha, or any other oil, naptha, or turpentine, that may be used for
dissolving india-rubber, &c., by any alkali or alkaline earths, and render it
or them caustic in the usual way, and dissolve it or any of them in water,
and run the fabric through this same liquor. The alkali which I prefer is
the common commercial caustic soda, diluted with water until it stands two
degrees by Twaddells' hydrometer; I run the goods through this mixture,
and then through water, and dry them in the usual manner, when the smell
(which usually accompanies what is termed "Macintosh's cloth," &c.) will be
found to have been entirely removed. This method of deodorizing may be
applied to silks, cottons, woollens, mixed fabrics, mohairs, or other similar
cloth or material.
I deodorize wood or any other material which has been impregnated with
tar oil, or any of the products from coal tar, by alkalies, caustic or otherwise,

page_text: in the following manner:-I take the wood, &c., so impregnated with tar,
oil, creosote, &c., and steep it in a solution of caustic soda, caustic potash,
caustic ammonia, or any alkali rendered caustic in the usual way, or any
two of them, and keep the same wood or material in this liquor for from two
to four hours, when it will be found to be free from smell.