A VARIETY OF COMPOSITIONS FOR MAKING A WATERPROOF CEMENT, MORTAR, AND STUCCO, THE SAME BEING ALSO APPLICABLE AS DURABLE COLOURING WASHES FOR BUILDINGS
Year: 1810

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDGAR
DOBBS, of the Borough of Southwark, Gentleman, do send greeting.
WHEREAS His most Excellent Majesty George the Third, by His
Letters Patent under the Great Seal of the United Kingdom of Great Britain
and Ireland, bearing date at Westminster, the Second day of August now
last past, did give and grant unto me, the said Edgar Dobbs, my executors,
administrators, and assigns, His special licence, full power, sole privilege and
authority, that I, the said Edgar Dobbs, my executors, administrators, and
assigns, during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, and Wales, and Town of
Berwick-upon-Tweed, my Invention of "A VARIETY OF COMPOSITIONS FOR MAKING
A WATERPROOF CEMENT, MORTAR, AND STUCCO, THE SAME BEING ALSO APPLICABLE
AS DURABLE COLOURING WASHES FOR BUILDINGS;" in which said Letters Patent
there is contained a proviso, obliging me, the said Edgar Dobbs, under my
hand and seal, to cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, 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, relation being thereunto had, may more fully and at large
appear.

page_text: NOW KNOW YE, that I, the said Edgar Dobbs, do hereby declare that
the principle of my Invention consists, first, in making by means of water,
a proper admixture of lime or its carbonats, with any one or more of the
following substances (viz.), clay, loam, mud, shale, road dirt or dust, soil, ochre,
cheap metallic oxides, ores, pyrites, blende, sand, stones, earths, ashes, and all
such earthy bodies (lime and its carbonats as before excepted), as can be
reduced to powder, and will not vitrify by the heat which they are subsequently
to undergo; secondly, in expelling the redundant water; thirdly, in burning
the mixture when in a concrete state; and, lastly, in reducing that mixture to
powder. This powder is the composition for making the cement, mortar,
stucco, and wash.
By carbonats of lime, I mean chalk, common lime, stones, marbles, oyster
and other marine shells, earths, and earthy bodies, that will slack or fall
into powder, either by contact of air or water, after being burnt by ashes, I
mean the unconsumed residue of coal or vegetable bodies after burning. The
process is this,-first, I reduce the lime or its carbonats to a fine state of
division, the lime by slacking, and the carbonats by grinding them, either with
or without water, by the common methods used for grinding whiting, white
lead, or flint, or by some other method equally effectual, until they are in
such a state of disintegration as, by subsequent agitation in water, will allow
the finer particles to remain in suspension a sufficient time to pour off with the
water from the grosser particles (which will have subsided and may again be
ground), and that the particles so poured off bo about as fine as those of
common whiting.
Secondly, I reduce the other substance or substances with which I want to
mix the lime or its carbonats to particles about the same fineness as those
before described; the hard ones, or those which require grinding, are reduced
either with or without water, and the finer parts when mixed with water
poured off as before; or if the selected substance or substances be sufficiently
soft of themselves, omit the grinding and simply diffuse them in water by
mixing and agitating them in it till the matter becomes of about a creamy
consistency, and then wash off as before.
Thirdly, I take certain portions of the washed lime or its carbonat,
according to the naturo of the required composition and of the other washed
substance or substances, and mix and incorporate them well together in a
vessel or other receptacle fit for the purpose; or the incorporation may be
made by adding to the bodies in their natural state a small quantity of water,
and then grinding and tempering them till they become homogeneous and

page_text: plastic. The diffused ingredients are then to rest, when the clear water is to be
drawn off and the remainder of it, evaporated (as is also to be the case if they
have been tempered) either by artificial heat or by exposure to the atmosphere,
till the mass becomes sufficiently stiff to be cut or moulded into pieces for
burning. The burning may be performed in a common limo kiln, stove, or
furnace, or even without any apparatus of that nature, observing that the
intensity and duration of heat be sufficient to consume the combustible part of
the ashes or fuel when contained in the mixture, and expel carbonic acid from
carbonat of lime without vitrifying any of the substances. The burnt pieces
are afterwards to be reduced to powder by grinding between horizontal stones,
or by any other means usually employed for grinding dry substances, and then
the composition is in a state fit for use. If the composition bo intended for
cement that will set in about ten or twenty minutes, and to be adopted to the
general purposes of building, the proportions should be (each of the ingredients
supposed to be in a dry state) about three parts by weight of chalk, or in lieu
of chalk one and half of lime, one part of such clay as is found in marshes on
the banks of the Thames, or such as turn red by burning, and one part ash,
such as is sold in London by the dealers in breeze. If it be required to set
sooner a greater proportion of lime or the carbonat must be taken, and if not
so soon a greater proportion of the other ingredients. If the composition be
intended for a wash to resemble stone, it will be proper to use pipe clay, or
some soft earth, free from iron or other colouring substances that will not burn
away, and omit the coal ashes altogether. If the ashes or any other com-
bustible substance be omitted in any of the mixtures either for the cement or
the wash, then fuel must be employed in the burning, either by stratifying
as in lime burning, or by any other convenient method at the discretion of the
operator; but when a proper quantity of combustible substance enters into the
compound, no extraneous fuel is necessary. To use the composition as a
cement or mortar, mix and temper it with water and apply it while in a
plastic state. To form and use the wash, add a sufficient quantity of water to
the composition as to make it capable of being applied with a brush as other
water washes are, taking care that it be used soon after the addition of the
water, as it will shortly slack or turn to a solid mass.
In witness whereof, I, the said Edgar Dobbs, have hereunto set my hand
and seal this Second day of February, One thousand eight hundred and
EDGAR (L.s.) DOBBS.

page_text: AND BE IT REMEMBERED, that on the Second day of February, in
the fifty-first year of the reign of His Majesty King George the Third, the
said Edgar Dobbs came before our said Lord the King in His Chancery,
and acknowledged the instrument aforesaid, and all and overy thing therein
contained and specified, in form above written. And also the instrument
aforesaid was stamped according to the tenor of the Statute made in the forty-
eighth year of His said Majesty's reign.
Inrolled the Second day of February, One thousand eight hundred and
eleven.