_Use._ To fix knives and forks in their handles. It is put into the hollow
of the handle, and the metal, previously made hot enough to melt the
composition, pressed into its place whilst warm, and the whole kept
upright and still until quite cold.
=Cement, Di'amond.= See CEMENT, ARMENIAN.
=Cement, Egg.= White of egg thickened with finely powdered quick-lime.
Used to mend earthenware, glass, china, marble, alabaster, spar ornaments,
&c. It does not resist long exposure to moisture unless it has been
exposed to heat.
=Cement, Elas'tic.= _Prep._ 1. Caoutchouc (in small pieces), 1 part;
chloroform, 3 parts; dissolve.
2. (Lenher.) Caoutchouc, 5 parts; chloroform, 3 parts; dissolve, and add
gum mastic (powdered), 1 part. Elastic and transparent.
3. Gutta percha, 3 parts; caoutchouc, 1 part (both cut small); bisulphide
of carbon, 8 parts; mix in a close vessel and dissolve by the heat of a
water bath. This is to be gently warmed before it is applied.
4. Gutta percha, 1 lb.; caoutchouc, 4 oz.; pitch, 2 oz.; shell-lac, 1 oz.;
linseed oil, 2 oz.; melted together. This must be melted before being
applied.
_Obs._ The cements 1 and 2 are elastic and transparent, and are applicable
to many uses. The others, 3 and 4, are used for uniting leather, cloth,
&c.
=Cement, Elec'trical.= _Syn._ CHEMICAL CEMENT. From black resin, 7 lbs.;
red ochre, 1 lb.; plaster of Paris, 1/2 lb. (both well dried and still
warm); melted together, and the heat and agitation continued until all
frothing ceases, and the liquid runs smooth; the vessel is then withdrawn
from the fire, and the mixture stirred until cooled sufficiently. Used to
cement the plates in galvanic troughs, join chemical vessels, &c. See
CEMENT, CAP, CEMENT, SINGER'S, &c.
=Cement, Engineers''.= _Prep._ 1. Ground white lead, mixed with as much
red lead as will make it of the consistence of putty.
2. Equal weights of red lead and white lead, mixed with boiled linseed
oil, to a proper consistence. Used by engineers and others to make
metallic joints. A washer of hemp, yarn, or canvas, smeared with the
cement, is placed in the joint, which is then "brought home," or screwed
up tight. It dries as hard as stone. It also answers well for joining
broken stones, however large. Cisterns built of squares stones, put
together, while dry, with this cement, will never leak or come to repair.
=Cement, Extempora''neous.= 1. Shell-lac, melted, and run into small
sticks the size of a quill. Used to join glass, earthenware, &c. The edges
are heated sufficiently hot to melt the cement, which is then thinly
smeared over them, and the joint made while they are still hot. This is
the cement so commonly vended in the streets of London, and which used to
surprise us in our boyhood days.
2. Tears of gum mastic, used in the same way. Commonly employed by
jewellers and others.
_Cement, Fire'proof._ _Prep._ From fine river sand, 20 parts; litharge, 2
parts; quick-lime, 1 part; linseed oil, q. s. to form a thin paste.
Applied to walls, it soon acquires a stony hardness. It is also used to
mend broken pieces of stone, stone steps, &c. See CEMENT, BEALE'S, &c.
=Cement, Flour.= _Syn._ PASTE, FLOUR PASTE. This useful and well-known
article is made by mixing about a tablespoonful of wheat flour with cold
water, (say) 1/2 pint, adding the latter gradually, and thoroughly
stirring in each portion before pouring in more; the vessel is then placed
over the fire, and the whole assiduously stirred until it boils, great
care being taken to prevent caking on the bottom, or burning. Some persons
add about 1/3 of a teaspoonful of powdered alum to the water, which is
said to strengthen the product; the shoemakers add a little quantity of
powdered resin to the flour, with the same intention. The addition of a
little brown sugar and a few grains of corrosive sublimate will prevent it
turning mouldy, and is said to preserve it for years. When too hard or
dry, it may be softened by beating it up with a little hot water.
=Cement, French.= Mucilage of gum Arabic, thickened with starch powder or
farina; a little lemon-juice is sometimes added. Used by naturalists in
mounting specimens; by artificial-flower makers; and by confectioners, to
stick paper, wafer papers, ornaments, &c., on their fancy cakes. Plain
mucilage is often used in the same way.
=Cement, Gad's.= _Syn._ GAD'S HYDRAULIC CEMENT. From clay (well dried and
powdered), 3 parts; oxide of iron, 1 part; mixed together, and made into a
stiff paste with boiled oil. Used for work required to harden under water.
=Cement, Glass.= _Syn._ GLASS FLUX. _Prep._ Red lead, 3 parts; fine white
sand, 2 parts; crystallised boracic acid, 3 parts; mixed and fused; it is
levigated, and applied with thin mucilage of tragacanth. Used for mending
broken china, &c. The repaired article must be gently heated, so as
partially to fuse the cement.
=Cement, Gibbs'.= Mr Gibbs patented in 1850 various processes for making
admirable building and architectural cements, equal in hardness and
duration, and superior in colour, to the best Roman and Portland cements
at present in use. His materials are obtained from "the vast beds of
(natural) argillaceous marls and marly limestones, or marl stones, which
contain the due admixture of lime, silica, and alumina, from which
hydraulic cements and artificial stones may be manufactured." These
materials he finds in "the chalk formation, the Wealden formation, the
Purbeck beds, the lias formation, the mountain limestone, and the lowest
strata of the coal-measures." After duly choosing his materials according
to the particular object in view, he prepares them "by burning in kilns,
and grinding in mills, in the way cement is now manufactured." Marls and
limestones are to be "first dried in kilns or ovens, at a heat fit for
baking, until all moisture be driven off, and that then the calcination be
prolonged as much as possible; the heat being kept as low as is only just
sufficient to effect complete calcination--this being indispensable, to
avoid the commencement of vitrification, which would destroy the adhesive
properties of the cement."
=Cement, Glue.= _Prep._ 1. From glue, 1 lb. melted with the least possible
quantity of water, and then mixed with black resin, 1 lb., and red ochre,
4 oz.
2. Glue, melted as above, and mixed with about 1/4th of its weight each of
boiled oil and red ochre.
3. (Ure.) Melted glue (of the consistence used by carpenters), 8 parts;
linseed oil, boiled to varnish with litharge, 4 parts; incorporate
thoroughly together.