AN IMPROVED PROCESS FOR PROMOTING THE ACTION OF THE ACETIC ACID ON METALLIC BODIES
Year: 1826

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HAM, late of West Coker, but now of Holton Street, Bristol, in the County of
Gloucester, Vinegar Maker, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Thirteenth day of June, 1826, in the seventh year of His
reign, did, for Himself, His heirs and successors, give and grant unto me,
the said John Ham, His especial licence that I, the said John Ham, my
exors, admors, and assigns, or such others as I, the said John Ham, my exors,
adiiors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, my Invention of "AN IMPROVED
PROCESS FOR PROMOTING THE ACTION OF THE ACETIC ACID ON METALLIC BODIES;" in
which said Letters Patent is contained a proviso, obliging me, the said John
IIam, 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 to 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 in part recited Letters Patent, as in and
by the same, reference being thereunto. had, will more fully and at largo
appear.

page_text: John Ham, do hereby declare the nature of my said Invention, and the
manner in which the same is to be performed, by the Drawing hereunto
annexed, and following description thereof (that is to say):-
I use my present Invention either in combination with or distinct from my
former Patent "for an improved process for manufacturing vinegar," and with
the variations herein described. First, I use it separate and distinct from tho
said Patent for the purpose of making white lead in the following manner :-
I cause a part of an inclosure or chamber (such as is at present used for the
same purpose), to be made water-tight by forming the bottom thereof, and
also the sides to the depth of about twelve inches, of bricks laid in roman
cement or by any other mode; and at the same time I affix a pipe and cock
into the said chamber or cistern, and rather below the bottom thereof, as
represented at A, Fig. 1, for the purpose of charging it with vinegar or
acetic acid through a, and discharging it through b; I then cause a pipe or
pipes of lead or other metal or material not acted upon by the acetic acid
whilst immersed therein to traverse the bottom of the said chamber or
cistern with a sufficiont number of turns or circumvolutions to impart the
heat of steam rapidly to the supernatant and surrounding liquid, the said pipe
or pipes having the extreme end or ends, one of them connected with a steam
boiler, and the other on the outside of the said chamber or cistern to allow of
the escape of tho condensed water or waste steam, as represented in Fig. 2nd
I now fill the cistern in the said chamber, and also the chamber itself, to the
height of three or four feet from the bottom, with refuse bark from the tanner's,
called tan, horse litter, or any sort of vegetable substance susceptible of a
similar d'ecomposition, and on the said bed of tan or other substance I place
flat layers of sheet lead, such as is used for the purpose by the white lead
manufacturers. These beds or layers are arranged alternately touching three
sides of the chambers, as represented in the Drawing annexed, so as to cause
the vapour hereafter described to ascend in the direction denoted by the arrows
until it reaches the top; the said beds or layers of lead are supported by laths,
rods, or staves, or even by perpendicular rolls of sheet lead, in order that the
acid vapour hereafter described may have the utmost possible contact with
the lead beneath as well as above each layer; and the mode of placing these
rods or staves need not be particularized further than to say that care must be
taken to place a sufficient number of other rods or supports crossways and
beneath each layer for the due support of the whole mass of lead and other
materials which will be resting thereon, and at the same time to keep the
different layers and supporting rods sufficiently apart from the bed of tan or

page_text: other substance, and also from each other, that a free course be allowed
between each for the ascent of the acid vapour hereafter described from the
bottom to the top of the whole stack or bed; and the top thereof is covered
over closely with boards or other materials, and a bed two or three feet deep
of the decomposed tan or other substance having a slow conducting power of
heat is placed thereon. Through the front wall of the said chamber at an
equal distance from the two side walls and nearly at the height of the surface
of the lower bed of tan or other substance, I insert a trunk or pipe of wood
or other material W, Fig. 1, sufficiently large to admit a thermometer
occasionally, and also for the purpose of furnishing a small supply of atmo-
spheric air, which enters between the surface of the said bed of tan or other
substance and the lowest layer of lead; and the said trunk or pipe is closed
with a stopper, having a hole of half an inch diameter only therein. I now
pour into the pipe a vinegar or acetic acid, until the surface thereof arises
therein (and of course at the same time in the cistern or chamber to which it
is attached) to the depth of about nine inches, but the quantity is perfectly
immaterial, as it can be removed and a fresh supply given as often as is
necessary. I then convey steam through the pipe or pipes before mentioned
so as to preserve the heat of the vinegar or acetic acid as nearly as possible
at 170 degrees of Fahrenbeit's thermometer, the vapour of which passes
through the bed of tan or other substance, and thence winds its way between
every layer of the superincumbent lead, the number of layers whereof will of
course depend on the quantity of vinegar allowed to corrode them; and on
their being a sufficient number of them to absorb all the acid vapour which
rises by the time it reaches the top, which may be ascertained by connecting
a small pipe to communicate with the space above the uppermost layer and
the external air, as at C, and on unclosing the mouth thereof which is not left
open, the vapour which rises through it can at any time be tested by the
known methods for indicating the presence of acetic acid; a wall of the
decomposed tan, horse litter, straw, or any slow conductor of heat of about a
foot thick supported by boards or other materials is interposed between the
sides or ends of the said layers and the wall of the chamber, as represented
at B, Fig. 1; to prevent the escape of the heat through the latter, I fill up
the customary entrance into tho said chamber with straw or horse litter in
such manner that part of it may be occasionally removed, in order to observe
the progress of the corrosion of the lead. The tan or other substance directed
to be laid at the bottom of the said chamber is renewed after it becomes
unsusceptible of farther decomposition, and the liquid therein is drawn off
through the cock after it has lost its acidity, if any should remain.

page_text: I do not claim the separate parts of this my Specification as my Invention,
but I claim as my exclusive right the combination of the particular arrange-
ments herein described, so that without the use of the customary earthenware
pots, the vinegar or acetic acid, and also the whole of the chamber or stack,
shall be heated by steam.
Secondly I promote the action of the acetic acid on metallic bodies by
combining together this and my former Patent "for an improved process for
manufacturing vinegar" in the following manner :-In place of the birch or
other material mentioned in the Specification of the said Patent, as presenting
an extensive surface, I substitute shreds or pieces of the metal intended to
be acted upon by the acetic acid, the said shreds or pieces answering the same
purpose as the birch therein described, by presenting an extensive surface to
the atmospheric air, so that the acidification of the vinous fluid, and the
corrosion and solution of the metal shall proceed simultaneously. This plan
is only available where the extract or mucilage contained in the vinous fluid
which is to be acidified has no injurious effect on the acetate to be formed;
when it has that effect, distilled vinegar is substituted for the said vinous
fluid, and the operation in both cases continued, and the degree of heat
imparted as described in my former Specification, and the contact with the
atmosphere permitted no farther than may be sufficient to decompose its
oxygen, which may be ascertained in the manner pointed out in my said
recited former Patent and Specification.
In witness whereof, I, the said John Ham, havo hereunto set my hand
and seal, this Eighth day of December, in the year of our Lord One