Year: 1886

page_text: Date of Application, 23rd July, 1886.
Complete Left, 19th Apr., 1887.
Complete Accepted, 20th May, 1887.
I, WALTER FRANCIS REID of Fieldside, Addlestone in the County of Surrey,
Civil Engineer do hereby declare the nature of this invention to be as follows :-
According to my invention I take the volcanic stone known in Derbyshire as
" toadstone or "dunstone" and I mix it with limestone or lime in such proportions
that the mixture of the two materials shall contain when burnt in 100 parts, 55 to 65
parts of lime. The materials may be either mixed in the shape of fragments or
pieces and afterwards ground, or they may be pulverized separately and then mixed.
The pulverized mixture is moistened with sufficient water to render it coherent,
and reduced to pieces of a convenient size for burning. These pieces are
when sufficiently dry burnt at such a temperature that they clinker, but do not
completely fuse.
llant hudpaulia namant

page_text: I, WALTER FRANCIS REID of Fieldside,. Addlestone, in the County of Surrey,
Civil Engineer do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :—
According to my invention I take the volcanic stone known in Derbyshire as
" toadstono "
or dunstone" and I mix it with limestone or lime in such proportions
that the mixture of the two materials shall contain when burnt in 100 parts 55 to 65
parts of lime. The toadstone is well known to geologists by that name. In its fresh
state it is of a dark colour resembling that of Portland cement clinker and is found
,in beds associated with the limestone. It is sometimes locally called "Dunstone."
In some places the layers of toadstone have undergone decomposition and are of a
brown colour; but this decomposed toadstone is equally applicable to the purposes of
my invention. The limestone found in the vicinity of the toadstone is suitable for
admixture with it. Should the limestone be used in a burnt state it must be mixed,
while fresh, with the toadstone to prevent the absorption of moisture from the
atmosphere which would cause the proportions to be variable. The materials
may either be mixed in the shape of fragments or pieces and afterwards ground, or
they may be pulverized separately and then mixed. The more finely the materials
are ground the better will be the quality of the cement and should the grinding be
coarse the finished cement will be deficient in hydraulic properties. The pulverized
mixture is moistened with sufficient water to render it coherent and reduced to
pieces of a convenient size for burning. The quantity of water required will vary
according to the porosity of the materials; in the case of compact limestone about 15
parts by weight of water will be required to moisten 100 parts by weight of the raw
mixture. When the limestone is previously burnt a larger proportion of water will
be necessary. These pieces are dried and then burnt at such a temperature that they
clinker, but do not completely fuse. The clinker when pulverized yields an excellent
hydraulic cement.
my
Having now particularly described and ascertained the nature of said invention
and in what manner the same is to be performed! I declare that what I claim is :
The manufacture of hydraulic cement from "toadstone
combination with lime or limestone substantially as described.
Dated this 19th day of Annil 1007
"
ог "dunstone" in
BREWER & SON,
For the Applicant.