AN IMPROVEMENT IN TREATING BONES, AND THE MANUFACTURE OF THE PRODUCTS THEREOF
Year: 1861

page_text: LETTERS PATENT to John Cowdery Martin, of High Street, Barnes, in
the County of Surrey, Naval Architect, for the Invention of "AN
IMPROVEMENT IN TREATING BONES, AND THE MANUFACTURE OF THE PRODUCTS
THEREOF."
Sealed the 7th February 1862, and dated the 15th August 1861.
PROVISIONAL SPECIFICATION left by the said John Cowdery Martin
at the Office of the Commissioners of Patents, with his Petition, on
the 15th August 1861.
I, JOHN COWDERY MARTIN, of High Street, Barnes, in the County of
Surrey, Naval Architect, do hereby declare the nature of the said Invention
for "AN IMPROVEMENT IN TREATING BONES, AND THE MANUFACTURE OF THE
PRODUCTS THEREOF," to be as follows:-
The Invention consists in the treatment or decomposition of bones by means
of hydrochloric or muriatic acid, for the purpose of obtaining the gelatine
and phosphate of lime, or earthy phosphates of which they are composed,
without the loss or destruction of either substance, and the recovery of such
acid for re-use, or otherwise. The bones, as clean and free from extraneous
substances as possible are submitted to the action of diluted hydrochloric acid
in a suitable vat or vessel, in which they or the solution are agitated from time
to time. The solution is drawn off after remaining on the bones until its
action has become very slow, a fresh solution of diluted hydrochloric acid is

page_text: then poured on the bones to dissolve out the remaining earthy phosphates.
The first and partly saturated or neutralized solution drawn from the bones is
used in another vat to commence the decomposition of a fresh supply of bones,
where its action is again visible, and it becomes more rapidly saturated with
the phosphate of line. The animal portions of the bones after the earthy
phosphates are quite dissolved out are to be washed in water, and all traces
possible of the solution removed, they are then to be boiled in water until
dissolved, and the gelatine so obtained is allowed to cool, and after being
cut into convenient pieces is again washed to remove any remaining trace of
acid, is again melted, poured into moulds, and dried in the ordinary manner.
Or after the first washing, the animal portions of the bone, then resembling
cartilage, are to be placed in a solution of soda in water, again washed, and
afterwards submitted to the action of sulphurous acid gas, again washed and
boiled until dissolved; the gelatine is allowed to cool, and is again washed to
free it from acid, again melted and cooled, and afterwards cut up and dried.
The solution of hydrochloric acid saturated with phosphate of lime is
evaporated to dryness, and the residuum submitted to heat in a closed retort,
and if the heat is sufficient, the whole of the acid is given off, and may be
condensed in ordinary receivers. If, however, the heat is not sufficient, or
continued long enough to drive off all traces of the hydrochloric acid, the
residue may be drawn from the retort and burnt, exposed to the atmosphere
in an open kiln, when phosphate of lime or bone ash will be the result. Or
the phosphate may be drawn from the retort before the whole of the acid is
driven off, and treated with sulphuric acid, and agitated in a suitable closed
retort, when the remaining hydrochloric acid will be given off, and may be
condensed, and a superphosphate of lime composed of sulphuric acid and
and phosphate of lime will remain.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Cowdery Martin in the Great Seal Patent Office on
the 15th February 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Jonn
COWDERY MARTIN, of High Street, Barnes, in the County of Surrey, Naval
Architect, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of

page_text: Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Cowdery Martin, Her special licence that I, the said
John Cowdery Martin, my executors, administrators, and assigns, or such
others as I, the said John Cowdery Martin, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "AN IMPROVEMENT IN TREATING BONES, AND THE MANUFACTURE
OF THE PRODUCTS THEREOF," upon the condition (amongst others) that I, the
said John Cowdery Martin, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Cowdery Martin, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by
the following statement, that is to say:-
My Invention consists in the treatment or decomposition of bones by means
of hydrochloric or muriatic acid, for the purpose of obtaining the gelatine and
phosphate of lime, or earthy phosphates of which they are composed, without
the loss or destruction of either substance, and the recovery of such acid for
re-use, or otherwise.
In carrying out my Invention, I select and prefer to use well developed
and solid bones, boiled or cleaned as free from extraneous substances as
possible, and at the same time in as small pieces as are readily obtainable,
which are placed in covered vats constructed of or lined with any material not
acted upon by the acid, each to contain about one ton of bones, and on which
is poured from sixteen to seventeen hundredweight of hydrochloric or muriatic
acid, of the strength of about 36 degrees Twaddle, previously diluted with
water to bring it to the strength of about 9 or 10 degrees Twaddle; or I use
half that quantity of acid with the whole of the water, and add the remaining
acid from time to time as the solution becomes neutralized. The bones are to
be agitated by simply stirring every three or four hours; or the solution may
be agitated, if preferred, by enclosing a space in the centre of the vat within a
square wooden case or trunk, having an enlarged perforated base. A loose
fitting wooden piston or agitator with a valve, which closes in its ascent, is

page_text: worked up and down within the case or trunk to agitate the solution, and
which, by means of four deliveries at the head of the case, disperses the
solution to the four corners of the vat, and is drawn again through the per-
forated base, and so circulated.
The solution after remaining on the bones until its action has in a great
measure ceased, which will be in about three or four days, is drawn or
pumped from the first vat, and is poured in a second vat over a similar
quantity of bones to those in the first vat, on which it is used to commence
their decomposition when its action is again visible, and it becomes more
rapidly saturated with the phosphate of lime or earthy phosphates. The
solution may remain on the bones in the second vat three or four days, and if
not saturated, may be again poured on a similar quantity of bones in a third
vat, for the more it is saturated with the earthy phosphates the greater will be
the economy in the subsequent processes of the manufacture to be presently
described.
After the removal of the solution from the first vat, there is then to be
poured over the partly decomposed bones remaining a solution composed of
eight or nine hundredweight of hydrochloric acid, of 36 degrees Twaddle,
previously diluted with three and a half times its volume of water to dissolve
out the remaining portion of the earthy phosphates, which generally takes
from two to three days longer, after which time it may be removed, and by
the addition of eight hundredweight of hydrochloric acid of 36 degrees Twaddle,
diluted with about twice its volume of water brought up to the strength of the
first solution used in the first vat, when it may be poured over the partly
decomposed bones in the second vat, from which the saturated solution has
been removed, and where it is allowed to further dissolve out the phosphates,
when it is in its turn removed to a third vat to become saturated, and
so on.
In case of any portion of the phosphates remaining after the removal of the
second solution in the first vat or the third, in any succeeding one a further
quantity of acid solution is to be used until all the earthy phosphates are quite
dissolved; what then remains in the vat is almost wholly gelatine, or capable
of boiling into gelatine, but preserving the original structure or form of the
bone, and somewhat resembling cartilage.
The animal portions of the bones, after the phosphates are quite dissolved
out, are to be washed in water, and all traces possible of the solution removed.
This may be done by submitting them to the action of clean water for four or
five days in a vat similar to the last, the water to be kept in circulation by
means of the agitating apparatus above described, and changed about every

page_text: five or six hours, and any remaining acid may be neutralized with lime water
or milk of lime, which is afterwards to be thoroughly washed out.
The cartilage or animal portions of the bones may be manufactured into
gelatine, glue, &c. in the usual manner of treating skins, and will almost
entirely dissolve on boiling, leaving nothing but a small sediment, and yield a
glue of far lighter color than the generality of glue in use. Or, for producing
a comparatively colourless variety of gelatine, the cartilages from the first
previously described washing may be macerated for about four days in a
solution of soda, rendered caustic by the addition of lime, from which they are
then to be removed, and the soda thoroughly washed out; this will neutralize
any remaining acid, and render them more susceptible of bleaching by
sulphurous acid, as is well understood in the manufacture of gelatine; after
which they may be treated in the usual manner of obtaining gelatine from
skins. The product of this operation is of great gelatinizing force, and when
obtained from the bones of animals used for food, may be employed for culinary
purposes.
After washing, and before any boiling, the cartilage or animal portion of the
bones may be sold as an article of commerce, and the bleached descriptions
are particularly suitable for the production of size in the manufacture of
paper.
The solution of hydrochloric acid from the macerating vats, saturated as
nearly as possible with the phosphate of lime or earthy matters of the bone is
submitted to heat to drive off the water in shallow evaporating pans, which I
prefer to be of cast iron, and not deeper than a foot or eighteen inches, and of
any convenient size, the pans to be filled up as the water evaporates, and as
the salts of lime fall down, when they may be removed and dried in the
manner practised in the manufacture of common salt (chloride of sodium) when
they will be ready to undergo the second treatment, to be herein-after
described. Or the solution may be evaporated to dryness when the pan has
been sufficiently filled up, the residuum to be stirred when it arrives at about
the point of solidification to render it more easy of removal. The pan is to be
fitted with a roof or dome of slate or vitrified brickwork or other material
capable of resisting the action of the acid, to which is connected two pipes to
conduct the vapour, one into the atmosphere, the other to a condensing worm.
When the solution becomes very much concentrated, and is approaching
dryness, a portion of the acid will be given off with the steam, when the
vapour is to be prevented escaping into the atmosphere, and conducted
through the worm placed in cold water kept constantly changed in the usual
manner, the worm to be in connexion with a set of ordinary acid receivers,

page_text: partly filled with water to condense any gas that may pass the worm.
The dried salts of lime or residuum after leaving the evaporating pans is
placed in any suitable furnace or retort used or capable of being used for the
evaporation or vaporization and recovery of acid. I prefer the cast iron
cylindrical retorts similar to those in use in the manufacture of sulphate of
soda by the decomposition of common salt set with sufficient area of furnace
bars and heating surface to admit, when required, of being brought up to a
full red heat, and to which retorts are luted or connected any of the usual
condensing apparatus in use for the condensation of muriatic or hydrochloric
acid. I prefer the ordinary receivers of the arrangement similar to Wolfe's
bottles for this purpose.
Within the retort is an iron rake or agitator, curved
to fit the bottom, the handle of which projects through a hole in the mouth
plate or door of the retort, the use of which is to occasionally agitate or stir
the contents. The handle of the agitator is to fit the hole in the mouth plate
as closely as is consistent with its free action, and when not in use the space.
round the handle may be made tight-with-clay or loam.
As the acid will leave the retorts in a too highly heated state when they are
brought fully up to redness, and be likely to overheat the condensing appa-
ratus when the ordinary receivers are used, I place a worm surrounded by cold
water kept constantly changed between the dip arm leading from the retort
and the first of the set of receivers. The gas on passing through the..worm-is
condensed by the water in the receivers in the usual manner. The salts of
lime after remaining in the retorts at a red heat for five or six hours, being
occasionally agitated at intervals throughout that time, will be found to have
parted with nearly the whole of the hydrochloric acid, and may then be with-
drawn, and any trace of acid yet remaining may be burnt out, if required, by
a furnace open to the atmosphere, or to which the atmosphere has access, for
which purpose I prefer a reverberatory furnace. In this the heat is continued
until the whole of the acid has disappeared, which may be known by with-
drawing and examining a small quantity, when phosphate of lime or bone ash
will be the result. Or the acid may be recovered from the salts of lime in
two or more operations without raising the retort to a full red heat or main-
taining it so long, which method, as it burns the retorts less, I prefer. The
salts of lime are placed within the retort, the heat of which is raised to a just
visible red, which is maintained for four or five hours, the contents are then
withdrawn and washed in water, when the greater portion of the salt will be
found to be insoluble and will fall to the bottom, having parted with nearly
the whole of its hydrochloric acid. I prefer to wash the phosphate or salt of
lime on a modification of the principle employed in washing the soda from the

page_text: black ash in soda works. I place four vats, each of about six feet square by
four or five feet deep, side by side, or in a square, in each of which a quantity of
the phosphate or salts of lime is placed; the first vat is then filled with water,
and the contents intimately mixed by stirring, the insoluble portion is then
allowed to settle down, when the liquor is pumped into the next vat, and the
first again filled with water, which operation is repeated until the liquor from
the first reaches the fourth vat, when it acquires sufficient specific gravity to
admit of boiling down in the previously described pans without the evaporation
of an undue amount of water. The residuum is the salts of lime, similar to that
obtained from the first process of evaporation in the pans, and may be again
placed in the retorts. The salts of lime in each vat is, by this arrangement,
subjected to four washings, and the water from one vat becomes in its turn
charged with some of the soluble portions of the salts of line contained in all
four. The precipitated phosphate of lime in the washing vats is removed and
dried, and will yet contain a small portion of hydrochloric acid, and will be of
a somewhat dark color owing to the solution from the macerating vats, and
from which the salt of lime was evaporated, containing small particles of the
organic or animal portions of the bone, which have become converted into
animal charcoal by the heat of the retorts. If the phosphate is required white
it is to be submitted to the action of the reverberatory furnace, above de-
scribed, when the color will be driven off with the small remaining trace of
acid. If, however, the phosphate is to be used in the manufacture of super-
phosphate of lime for agricultural purposes, where color is not an object, by
the addition of sulphuric acid any small remaining quantity of hydrochloric
acid would be given off and ordinary superphosphate of lime remain. The
phosphate of lime may, however, on being drawn from the retort at once, and
without the previous washing above described, be submitted to the action of
sulphuric acid for conversion into superphosphate of lime, for which purpose
it is placed in any suitable closed tank or vessel, which I prefer to be cylin-
drical, and is to be capable of resisting the action of the acid, and to have a
shaft with arms working through the centre for the purpose of agitating the
contents, such vessel to be in connexion with a condensing apparatus, similar
to that above described, when the hydrochloric acid may be condensed as it
is given off by the sulphuric acid, should the quantity be thought of sufficient
5 value.
Having now described and ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I would have it clearly
understood that I do not confine myself to the precise details above set forth,
and I do not claim as my Invention separately the decomposition of bones by

page_text: the bydrochloric acid solution for use in the manufacture of gelatine, as the
process has long been well known, nor the stirring or agitating such solution;
but what I claim as my Invention and wish to secure by the said Letters
Patent is, the treating bones with bydrochloric acid applied to bones in suc-
cession until the hydrochloric acid is saturated with earthy phosphates, and
the obtaining phosphates or superphosphates from such saturated solution by
evaporation, as above described.
In witness whereof, I, the said John Cowdery Martin, have hereunto
set my hand and seal, this Fifteenth day of February, in the year of
our Lord One thousand eight hundred and sixty-two.
JOHN COWDERY MARTIN. (L.S.)