IMPROVE. MENTS IN THE MANUFACTURE OF CEMENT, MORTAR, CONCRETE, AND ARTIFICIAL STONE
Year: 1856

page_text: LETTERS PATENT to Edward Loos, of No. 30, Leicester Square, in the
County of Middlesex, Civil Engineer, for the Invention of "IMPROVE.
MENTS IN THE MANUFACTURE OF CEMENT, MORTAR, CONCRETE, AND ARTIFICIAL
STONE,"
Sealed the 19th June 1857, and dated the 20th December 1856.
PROVISIONAL SPECIFICATION left by the said Edward Loos at the
Office of the Commissioners of Patents, with his Petition, on the
20th December 1856.
I, EDWARD LOOs, of No. 30, Leicester Square, in the County of
Middlesex, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF CEMENT, MORTAR, CON-
CRETE, AND ARTIFICIAL STONE," to be as follows:-
1 take lime, sand, and other materials of a coagulative, siliceous,
argillaceous, clayey, chalkey, aluminous, alkaline, absorbing, and
coloring nature, as also natural and artificial sulphates and carbonates,
as I may require. The whole of these ingredients, matters, or substances
I prepare, and combine either with or without the application of heat,
by which I produce a cement or mortar applicable to all building and
artistic constructions, and more especially for the manufacture of my
improved Roman concrete and blocks of hard artificial stone, which I
produce as follows:-I take certain qualities and quantities of the
aforesaid improved Roman cement and mortar, according to the purpose
for which the said concrete and stone are required, and mix them with
ordinary hydraulic materials or matters, such as are commonly used
for building purposes. I also mix therewith such other materials or
substances as have not heretofore been generally used for building
purposes, such as pebbles, shingles, flints, gravel, sand, and earthy sub-

page_text: stances of a calcareous, chalky, gypseous, siliceous, clayey, or alkaline
nature, rubbish, or stones, siliceous minerals, quartz, silex, bricks, tiles,
refuse from stonemasons' works, refuse clinkers and cinders from metal
works, and other similar substances, and, according to the nature and
proportions of the materials, I add divers substances of an alkaline,
aluminous, clayey, and absorbing nature, and sometimes natural or
artificial sulphates and carbonates suitably prepared, and I cast or
run the concrete into the desired shape for building and artistic purposes;
and in like manner I shape artificial stone, either plain, ornamental,
sculptured, or colored, as desired, or I shape the said stone with tools,
as commonly practised. All the above-mentioned improved products I
propose to render of great strength, as also impervious to the action of
atmospheric and other influences and acids, by applying thereto (either
before or after the materials are put together or shaped, as the case may
be,) chemical preparations composed of silicates, biphosphates, resinous
oils, and compositions of a similar character, by which I preserve the
surface of the material.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Loos in the Great Seal Patent Office on
the 20th June 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
Loos, of No. 30, Leicester Square, in the County of Middlesex, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of December, in the
year of our Lord One thousand eight hundred and fifty-six, in the
twentieth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Edward Loos, Her special licence
that I, the said Edward Loos, my executors, administrators, and
assigns, or such others as I, the said Edward Loss, my executors, admi-
nistrators, 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 "IMPROVEMENTS IN THE
MANUFACTURE OF CEMENT, MORTAB, AND ARTIFICIAL STONE," upon the con-
dition (amongst others) that I, the said Edward Loos, my executors,
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain

page_text: 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 Edward Loos, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
I manufacture Roman mortar of different qualities, according to the
use for which it is destined, with a certain proportion of lime, that is
to say, with a given quantity of any description of lime, and a chemi-
cally calculated quantity of moderately fine sand and powdered sub-
stances of a siliceous, argillaceous, aluminous, alkaline, coagulative,
and coloring nature, as well as natural and artificial sulphates and
carbonates, according as may be required. All these substances are
prepared in a certain manner, with or without fire, and their precise
combination and suitable manipulation give to my mortar the greatest
possible hardness, and the qualities of the best cement and mortar, and
render it applicable to all the uses of common or hydraulic mortar,
puzzolana, and other analogous cement and mortar, and to certain other
uses. such as casts in bas-relief, ornaments, statues, and artistic
mouldings, which become impermeable to moisture, and of a smooth
and brilliant surface, like marble, and stucco, or plaster of Paris;
they give, in fact, to works and constructions the solidity, tenacity, and
unalterable density of ancient Roman mortar and cement. Three
species of substances, abundant in nature, enter into the composition of
my improved cement and mortar, namely, lime, sand, and clay, either
in a burnt or raw state. The materials which enter into the composi-
tion of my cement and mortar are composed of two general bases or
elements, namely, the hydraulic bases and ordinary bases. The first
gives to the lime and to the mortar the quality of hardening more or
less quickly in water and under the influence of moisture, and consti-
tutes the chemical elements which combine intimately with the lime,
forming one body with it, and then passing together into the state of
cement or hydraulic mortar. The lime does not combine with the
materials of the ordinary bases, but surrounds them and binds them
physically together; they remain in their physical elementary state:
Their mixture with the lime forms ordinary mortar; by adding a given
proportion of hydraulic bases its qualities may be considerably
augmented, and renders it impermeable to moisture. The ancient
Roman mortars combine these qualities. This real knowledge of the
nature of the materials to be employed, and of the proportions of the

page_text: hydraulic ordinary "or anti-hydraulic elements which compose these
materials, is absolutely necessary to obtain the normal composition, the
best mortar and cement. My improved mortar, No. 1, composed of
half the weight of its hydraulic base, hardens completely in water
the second day. My mortar, No. 2, composed of two-fifths of
the weight of its hydraulic base, hardens in water only about the
eighth day. My mortar, No. 3, composed of one-fourth of the weight
of its hydraulic base, does not harden under water until about the
twentieth day. The consistence of these mortars in water encreases
with age, and my processes of manufacture render them more economical
than the mortars ordinarily employed. The hydraulic bases form the
active part of my mortars, and give to them the principle of great
strength and power of resistance. Moisture and atmospheric influences,
instead of being detrimental, are favorable to them, and by my system
they may be employed during the fusion of the lime which enters into
their composition, so as to give instant and complete dryness to the
masonry.
I find the quantity of pure lime contained in any description of lime
gives the peculiar property over all other matters of absorbing three
or four times its weight of water. I find the degree of the hydraulic
base of the lime, or the matters I employ to be used for the composition
of my Roman mortars, by forming with slaked lime a paste of the con-
sistence of mortar employed in good ordinary masonry, or in forming
with 9 parts in powder of the matter to be employed (mixed) with two
parts of pure lime a paste of the same consistence, and putting this
paste in a vase of tin or galvanized iron, pierced with holes all the way
up, and placing this vase under water. If the paste hardens the second
day the substance is of hydraulic base, No. 1; if it does not harden
until the eighth day it is of the hydraulic base, No. 2; and if it does
not harden until the twentieth day it is of the hydraulic base, No. 3;
lastly, if the paste instead of hardening softens under water, the sub-
stance under trial is of the ordinary base, without hydraulic properties.
Natural puzzolana baked by volcanoes, artificial puzzolana, baked
bricks, tiles, calcined pit coal, all burnt clays and matters, schiste,
shales, basalt, argillaceous and siliceous sand, ferruginous freestone;
granite, the powder and cinders of all these matters, carbonates,
alkalies, &c., are with lime the substances in which the most hydraulic
bases are to be found I use these and similar substances in the combined
relative proportions that each country offers to me, whether in powder or
in fragments more or less large, for the cold or hot composition of my
Roman mortars and cements, to which I add, according to the nature
of the works, at the same time it is about to be employed, a certain

page_text: quantity of carbonate of lime in powder, of sulphate of lime or alkalies,
either singly or mixed together, beforehand or at the moment of their
being employed.
My mortars acquire great durability, great power of resistance, a
greater or lesser quantity of hydraulic properties and tenacity, by the
mixture and combination of matters of hydraulic bases, and in com-
posing them with sand and the hardest materials in fragments more or
less small, such as porous siliceous argillaceous sand, ferruginous or
quartzous freestone, dross from forges and volcanoes, and other
analogous matters. My processes in manufacturing my Roman mortars
of the ordinary bases and the hydraulic bases consist in mechanically.
and roughly separating the substances, and in dividing them into
physical or granulated parts, and chemical parts or powders.
The
chemical parts. being the only ones that form one body with the lime,
are added first to the slaked lime in a suitable paste and mixed with
it, mixing the whole with rakes, wooden beaters, or other appropriate
instruments. The best proportions are from three to nine parts by
weight of sand or earth with one part of pure lime. My process of
separating the sand, clay baked or raw, and matters whatever in
chemical elements in powder, and in physical elements, is of two
natures, according as these matters are in a dry or moist state. Firstly,
if the substances are dry, I separate them by passing them through a
metal wire sieve as used for plaster, or in cylinders as used for sifting
meal. The powder passes through the sieve and the sand remains mixed
in different sizes; this is then subdivided in a similar manner in suitable
sizes, to diminish at will the quantity of liquid mortar employed in
works of masonry by the addition of fine sand or matters of a given
size. The powder is then measured apart, according to the analysis
of the matters, in order to constitute the chemical part of the mortar,
and to manufacture, firstly, the finer and more liquid mortars; secondly,
if the matters are of a moist nature, I separate them in chemical parts
and in physical elements by washing. This operation is repeated: until
the water remains liquid after the agitation; after this operation there
only remains in the receptacle physical elements, or parts more or less
large of sand or other matters. After some hours the muddy water
will depose the chemical elements diluted by it, which will fall to the
bottom. The clear water is then decanted, and the rest dried in the
air or at a stove. The powder thus obtained is then put aside in the same
manner as that obtained by the dry process, to be used, as above
described, in the manufacture of mortar and cement. The sand and
granulated parts rich in hydraulic bases may be pounded as may be
necessary, and submitted to the same, operations for extracting all the

page_text: chemical and hydraulic elements as are employed in making these
hydraulic mortars. These same processes on a small scale serve to
analize the matters to ascertain their hydraulic richness, as above
explained. When my mortars, thus composed of suitable qualities of
lime and chemical elements, are made into a suitable paste, they are
put aside to be used in the different works for which they are intended.
It is easy to understand that by the combination of powders contained
in the composition of my mortars, quality, consistence, and even the
color desired can be given to them. Such desired consistence is then
given to the mortars, and they are rendered fit for any kind of work
by adding in their composition sand, gravel, flints, clay, baked or raw,
and mineral matters of whatever sort may be used at will. The pro-
portions of these mixtures of physical elements for producing my
improved mortars for masonry are the four following combinations:-
First, for my mortar of sand or middling materials I combine one
hundred parts of sand or middling materials with twenty-five parts of
fine sand and thirty-five parts of pure lime.
Second, for my mortar of coarse sand or materials I combine one
hundred parts of sand and coarse materials with about twenty or twenty-
five parts fine materials and thirty-five parts of pure lime.
Third, for my mortar made of gravel or other materials of a some-
what similar kind as regards the size of the particles, I combine one
hundred parts of gravel or other suitable materials with ten parts of
sand or middling materials, twenty parts of fine sand and materials,
and thirty parts of pure lime.
Fourth, lastly, for my mortar made of pebbles or other materials of
similar size thereto I combine one hundred parts of pebbles or other
materials of about two inches in size with five parts of gravel and sand or
other materials of about half an inch, ten parts of sand and materials
of about one sixty-fourth part of an inch, 20 parts of very fine sand, and
thirty parts of pure lime.
These combinations and proportions of materials added to my mortars
are the most economical, and give to the composition and to the con-
struction of the masonry itself, or to my artificial stone moulded from
them, all the tenacity, solidity, and hardness of ancient Roman mortars.
Pure lime without action of its own upon the materials, which it serves
to bind together and physically to encompass, passes into the state of
energetic cement when it is combined with hydraulic bases, and in this
state it has a very great affinity for all granulated matters, with which
it combines itself intimately and strongly in proportion to the absorbtion
of water which has entered into its composition. I have found from
this rule, and the law applicable to my chemical composition, and to

page_text: the practical manufacture of my mortars and cements, as well as to my
artificial stone and real Roman masonry, I give to my mortars and
cements the hydraulic qualities I desire by means of the proportions of
hydraulic bases which i add to the lime and other materials found at
hand, which I use in their composition. I manufacture my hydraulic
cements and mortars either with or without heat, according to the
purposes for which they are destined; I combine also these two sorts
of cement together, as required, in the given proportions, with
carbonates or sulphates of quicklime for works which require quickness
of action and rapid dryness. I manufacture them cold on the spot,
either when constructing or beforehand, by mixing the specified propor-
tions of lime with the specified proportions of hydraulic bases, either
dry or in a paste. I manufacture them hot by amalgamating the fixed
proportions of lime and substances of hydraulic bases, sifted and mixed
with the necessary quantity of water to obtain a firm paste, reducing
them into small masses or heaps, which I allow to dry in the air or
at a stove; I then pound them into pieces of an eighth to a quarter of
an inch in size, or into powder, which I spread in layers of about the
same thickness upon plates of metal heated to a red heat, and leave it
to bake, exposed to the atmosphere for about half an hour; I then
reduce it to fine powder, which I preserve for the manufacture of my
cements of the desired proportions of hydraulicity. I employ the lime
either quick or slaked; or for the manufacture of masonry, artificial
Roman stone, and sculptural or architectural ornaments, as manu-
factured in plaster. I thus obtain my hydraulic cements as energetic
as is possible, alike unchangeable to water and moisture as to dryness.
In this manner I manufacture very economically my stone and masonry
in Roman blocks of all forms, colors, and ornamental shapes desired,
with the fixed proportions of my new mortars and Roman cements
added to a given quantity of the materials used in the construction that
may be at hand, of whatever nature and mineral bases they may be,
such as fine, middling, and coarse sand, gravel, flints, pebbles, and even
clay of a calcareous, silicious, argillacious, or alkaline nature, pieces
of refuse stone, ferruginous freestone, and all decriptions of quartz,
silex, granite, stone, rubble, refuse of bricks, tiles, and crockery, and
all descriptions of clinkers, slags, cinders of all kinds, and all similar
matters found at hand I add to the mortar, and thus amalgamate with
a rake or other appropriate instrument; or, mechanically, a fixed quan-
tity of materials of a silicious, argillaceous, alkaline, aluminous, and
absorbing nature. I obtain by these combinations a positive chemical
reaction of all these matters towards each other, facilitated by a suit-
able manipulation, which combines the whole into one mass strongly

page_text: cemented, and rapidly attains the hardness of stone, and becomes to
the action of the air and moisture as tenacious and of analogous cohesion
to ancient Roman constructions. I manufacture of all sizes in appro-
priate moulds my artificial Roman building stones in blocks and sand
either beforehand or on the spot when raising the walls. My moulds
in metal, wood, or other suitable substance, of any desired shape, plain
or in ornaments of architecture or sculpture, are composed of one single
piece, or several pieces solidly united, as may be required. If my stone
for Roman constructions is made in advance, the work should be accom-
plished in the workshop, and the moulds placed under a shed or such
other appropriate place. If the stone is required to be made as fast as
is required for the elevation of the walls, the moulds should be disposed
on the spot where the construction is to be raised. The workman proceeds
as follows: Either in the manufacture of my Roman stone, or in raising
walls, several casks provided with moveable covers are placed in the
building yard; one of these contains a certain quantity of my Roman
cement No. 1 in a paste, that is to say, of half the hydraulic property;
a second, of half-slacked lime in a state of powder; a third, of sulphate
of lime or plaster powdered and sifted, or, if necessary, my chemical
elements in powder, as above described; a fourth, of dry argillaceous
earth or fine silicious sand passed through a sieve; lastly, a fifth, about
half a cubic metre, or about 18 cubic inches of water, containing about
half per cent. of ordinary gelatine in solution, one per cent. of alum,
one per cent. of skimmed milk or buttermilk a solution of potash, and,
if necessary, a solution of a suitable quantity of yellow ochre, Italian
or other earth. If the question is of ornamented moulds or of price,
half a hod of very fine Roman mortar No. 1 should be used, composed
of fine sand and other binding substances. If the moulds are plain, a
hod of my mortar No. 2 should be used. The workman forcibly mixes
the contents of the hod with his trowel, and introduces a quarter of a
hod of my mortar from No. 1 cask, and a certain quantity of the
chemical solution contained in No. 5 cask, and at least an equal quantity
of sand or powdered matters from cask No. 4. These are mixed well
together, and a certain quantity of the powdered quicklime from cask
No. 2, and a suitable quantity from No. 3 cask, according as may be
found necessary, the whole being well mixed together; a double quantity
of the contents of cask No. 2 may be substituted for the mixture in cask
No. 3. As soon as it is found by its rapidly binding that the mortar is
in a fit state, I work it by means of a pipe or trough into a stucco or
plaster of about one and a half inches thick upon the wall or other part
to be covered, and all round the mould to the height of about eight to
fifteen inches high by about three feet long. During the time the work-

page_text: man is doing this work another workman prepares a hod of mortar
No. 3 and a hod of mortar No. 4, mixed well together with
a trowel; he adds a certain quantity of quicklime in powder,
or of plaster or cement, and an equal quantity of sand or
powdered matters; these the workman mixes well together in the hod
containing the mortar No. 3 for the blocks, while his assistant does the
same with the other hod, and as soon as he finds that the mortar is
active he plasters quickly over the whole bottom of the mould the mortar
No. 3 about 12-inch thick, which he smooths and equalizes by means of
a piece of wood of suitable length and width, which he strikes rapidly
with a mallet over the whole length; he then deposits quickly over this
layer of mortar No. 3 a similar layer of mortar No. 4, which he gently
smooths and flattens in the same manner. He again recommences these
successive operations until he has used all the mortar contained in the
two hods. The workman employs either old or new bricks in the
interior of the mould; he places them lengthways in a row upon each
bed or layer, or upon each double bed or layer of the mortar, but not
joining each other, and alternately another row lengthwise or cross-
wise, if the thickness of the mould permits, taking care to place the
joints of the bricks alternately. The workman successively recom-
mences these operations until the mould is full. If he manufactures
my Roman stone at the workshop, he proceeds in the same manner as
for the construction of the house on the spot, and for the construction
of vaults and masonry from rubbish.
The workman or mason smooths and flattens with care his wall,
according to the form and circumscription of his mould, plain or
ornamented. He may thus successively continue his work during the
whole erection of the house or building.
The same process takes place in partitions made of my rubbish
mortar, in the same manner as they are made of bricks and mortar, as
explained above, only that the workman should take care to add a
larger quantity of sand or argillaceous earth, even to the proportion of
three-quarters, when erecting a cheap construction.
It is not necessary to employ the fine hydraulic mortar from cask
No. 1, nor the liquid from cask No. 5, but merely my rubbish mortars
Nos. 1, 2, 3, or 4, and for the stuccos or plasters our rubbish mortar
No. 1, which he renders more active and energetic by the addition of
ordinary lime plaster or my hydraulic cement, and for want of both
any of these mortars.
For underground constructions the workman does not employ sulphate
of lime in the composition of the mortar. If the soil is damp or
exposed to water, he adds a certain quantity of any extreme hydraulic

page_text: mortar and sands, and hydraulic matters in powder, according to the
greater or lesser degree of dampness of the ground. He establishes on
the area of the ground or cave a layer of from about one and a half
inches to three inches thick, of my building mortars Nos. 2,
3, and 4, rendered more or less hydraulic according to the
nature of the soil.
In the same manner the planks of roofs
may be fixed, for rendering them completely hydraulic, by
building cach one in any convenient
manner with successive
layers of my rubbish mortar or graduated hydraulic properties, the
first layer forming the ceiling of the room underneath, made like the
interior partitions of walls, successive layers augmenting the hydraulic
properties until the last is on an inclined plain, if the plank is to form
a terrace, like Italian houses, and those of northern and eastern
countries.
For certain more massive constructions I unite my process with the
ancient system of Roman building, such as is found in the monuments
and ruins in existence at the present time. I form a double pavement
or incasing of bricks or other suitable stones, or of any artificial Roman
stone, and add any rubbish mortar in this incasing, regularly building
each layer. For ceilings I first lasth them in the usual manner; I make
a false ceiling, forming the mould with cornices or suitable ornaments,
if required. The workman then makes the ceiling in the same manner
as walls, using for the first layer my fine mortar. The layer must be
put on with great care, mixing with it my buildings mortars Nos. 1 and
2, well filling up the spaces and intervals produced by the laths. If
the ceiling is required to be plain, the workman adds to this first layer
of about one inch or one and a half inch thick, a second, or even a third
layer of my building mortars, Nos. 3 and 4, of the thickness of about
one inch and a half.
To increase the hydraulic properties of the materials employed, I give
to the exterior one, two, or three warm coatings of my chemical solution,
which not only applies to my hydraulic terraces and to my materials in
which the greatest dryness is desired, but serves also for my foundation
planks, and in the preparation of wood generally, iron, and materials
of all descriptions which I desire to secure against dampness, atmos-
pheric and other deleterious influences, even the most corrosive chemical
agents.
When it is required to prevent even imperceptible dampness, I apply
one or two coatings of a solution of silicate or phosphate of lime, which
does not change the color of my mortar or artificial stone.
When there is no risk of the color of the materials changing, I then
prepare a more impermable chemical solution, which I compose and
+

page_text: apply in the following manner:-I first put into an iron vase, heated
on the fire, about fifty-six pounds, avoirdupoise, of shale, or mineral oil,
or tar, one hundred weight of dry pitch and tar, mixed rosin, bitumen,
or other resin, taking care to mix them well together; I then divide the
mixture into two parts and pour same into two other stoppered vessels,
adding to the mixture in one of the vessels about two and a quarter
pounds of sulphate of iron, and about fifty-six pounds of powdered
cement, or fine dry siliceous sand, agitating the mixture until the
ingredients become perfectly combined. In the second vessel I add
about fifty-six pounds of schistous oil or other analogous mineral oil;
the whole mass is then agitated quickly, and then drawn off into suit-
able vessels. In applying the above mixture, we place it in a wrought-
iron boiler and heat the same to a temperature exceeding that of
boiling water; into this chemical bath I immerse my artificial materials,
and by these means get rid of any moisture they may contain.
Wood,
iron, copper, bricks, stones, or other substances may be similarly
operated upon for about a quarter of an hour, and then taken out and
separated and left to dry, when they will be fit for use.
The materials thus prepared may, if necessary, receive a slight coat-
ing of my improved solidified cement, softened for this purpose in an
iron vessel. This coating may be applied by means of a large brush or
iron spatula while in an almost boiling state. Two substances thus
coated when placed together become when cold inseparably united.
The addition of sulphate of iron in the above preparation may in certain
cases be omitted, and the cement itself as well as the sand may be
advantageously replaced by a further quantity of rosin, gum lac, or
dry pitch and tar.
Having now described the nature and object of my said Invention of
"improvements in the manufacture of cement, mortar, concrete, and
artificial stone, together with the best means I am acquainted with for
carrying the same into practical effect, I hereby declare my Invention
to consist in, and I claim the manufacturing of cement, mortar, con-
crete, and artificial stone in the manner and by the means above stated,
reserving to myself the right of varying the proportions and thicknesses
of the materials, as above described.
In witness whereof, I; the said Edward Loos, have hereunto set my
hand and seal, this Twentieth day of June, in the year of our
Lord One thousand eight hundund and fr
0 Witness,
ALEX PRINCE, Agent for Patents,
4, Trafalgar Square.
E. LOOS. (L.S.)