IMPROVEMENTS IN THE MANU- FACTURE AND ANNEALING AND NOVEL APPLICATIONS OF GLASS, AND IN THE MEANS AND APPARATUS FOR EFFECTING THE SAME
Year: 1875

page_text: LETTERS PATENT to Edward Henry Cradock Monckton, of Fineshade,
Northamptonshire, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE AND ANNEALING AND NOVEL APPLICATIONS OF GLASS, AND IN THE
MEANS AND APPARATUS FOR EFFECTING THE SAME."
"
COMPLETE SPECIFICATION filed by the said Edward Henry Cradock
Monckton at the Office of the Commissioners of Patents, with his
Petition and Declaration, on the 21st September 1875, pursuant to
the 9th Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HENRY CRADOCK MONCKTON, of Fineshade, Northamptonshire, send
greeting.
WHEREAS I am in possession of an Invention for “IMPROVEMENTS IN
THE MANUFACTURE AND ANNEALING AND NOVEL APPLICATIONS OF GLASS, AND IN THE
MEANS AND APPARATUS FOR EFFECTING THE SAME," and have petitioned Her
Majesty to grant unto me, my executors, administrators, and assigns,

page_text: by the following statement:-
My improvements consist,-
Firstly. In placing glass after its manufacture, either cold or as it
comes warm from the hands of the maker, into a bath filled simul- 1
taneously with the ingredients herein-after detailed; this bath is then
subjected to a gradually increased heat, varying according to the nature
of the glass to be annealed, and its ability to resist heat to the extent
that it can sustain without losing shape. It is usually retained in this
bath for a time corresponding to the ordinary process of annealing, 1
being in like manner cooled gradually down, but the length of time may
be varied to suit the purposes for which the glass is required; thus for
glass required for chemical purposes and to resist heat and fracture, the
longer the process is kept up the better, but three days will suffice in
most instances to effect all that is desired, while 12 hours or even much 2
less will do for ordinary glass.
Secondly. In again heating glass when finished which while red hot or
at a heat that it can sustain without losing shape is plunged into the
heated material forming my bath, and the time necessary for heating
up the cold material is saved, but it must be retained in the hot 2
bath and be subsequently cooled very gradually, the length of time
depending as in the first process on the object for which the glass is
required.
Thirdly. In applying these processes to glass already previously
annealed in the ordinary way which is further improved in quality 8
thereby.
Fourthly. In annealing glass as is now done by means of a hot blast
or of superheated steam instead of the heat as ordinarily applied.
Fifthly. In using wrought or cast-iron pans or tanks for constructing
my baths with or without moveable covers which I either close or not at 8
pleasure.

page_text: Sixthly. In applying grooves or divisions to the sides or ends of my
baths into which I insert the sheets of glass, so as to sustain and keep
them apart while immersed in the fluid or material constituting my
bath.
Seventhly. In applying taps to the bottoms or lower parts of my
baths, by means of which I draw off at pleasure the fluid contents, and
after cooling remove the glass. I also by this means wash the glass
while so placed and drawn off the liquor as often as I please till the glass
is sufficiently clean.
.
Eightly. In applying, various novel ingredients for forming my, baths
such as soluble glass, fused chloride of lime, fused soap, fused salt, as
common salt, saltpetre, alum, vitrol, and the sulphates, nitrates, and
chlorides of soda, potash, and lime, with the addition of water; I also
mix my salts as thus:-To 4 parts chloride of sodium I add alum 1 part
and saltpetre a quarter part; I also use grease and oils but preferably
linseed oil mixed with litharge; the ordinary oils I also use, but prefer
using them or grease combined with alkaline leys with or without the
addition of litharge so as to form soapy compounds; I use resin, tar, and
pitch, also as well as the alloys of metals casily fusible, such as those
made of tin, lead, and bismuth, or of tin, lead, bismuth, and mercury, or
of tin, lead, and spelter, each by themselves. The former baths I use for
the softer, the latter or metallic for the harder glasses, on account of
their ability to sustain heat. For this purpose I also use sand or ground
glass, or ground clays, or gypsum, or lime; I attach little importance to
and make no claim to the mere immersion of hot glass in hot fluids, and
then taking them out, but the greatest possible importance to the length
of time it remains in them, so that it may undergo the process of
annealing and that molecular change which while it toughens prevents
brittleness, and be then gradually cooled down. The length of time
required for annealing depends entirely on what the glass is required
for, the commoner and cheaper sorts not requiring so much strength and
consequently a shorter time will suffice.
Ninthly. In making baths that pay their cost. Thus it will be seen
that linseed oil boiled with litharge eventually forms a drying oil, so
that this bath after a time instead of being wasted will be saleable as
painters' drying oil. The oil and alkaline ley baths forming soaps will
be eventually disposable of as soaps, in either case the drying oil or soap

page_text: can be removed from the glass by the addition of alkaline leys or water,
which will go again to form fresh soap baths. The chloride of lime can
bo reduced in heating power by the addition of water, and being readily
soluble can be washed off and the liquid bo used again with fresh baths,
so that scarcely any waste occurs in this case, besides which this and the 5
salt baths generally do not require to be covered, and are free from fear
of taking fire as is the case with oil, when used alone, or with resins,
pitch, and tar, and their compounds with oil, which are dangerous and
give out bad odours and which therefore as a rule I prefer not to use.
The glass when annealed sufficiently is allowed to cool in the hot water 1
or other hot solvent put to cleanse it after the fluid composing the bath
has been run out.
Tenthly. In some cases the glass is removed from one bath to another
after being in it for an hour or more; thus hard glass is heated and
immersed in a soap bath, and then again heated and immersed in a 1
chloride of lime bath at a higher temperature, and after an hour or more
in that be immersed at a still higher temperature in a fused alloyed
metal bath, and be left there till the annealing process is completed.
This process is recommended for chemical vessels and for thin fine glass
requiring strength, as for cases for watches, which thus prepared could 2
be substituted for metal.
Eleventhly. As glass is ordinarily composed of lead, oxide, silica,
alkali, and lime, in using a mixture such as of lithargo with oil, soluble
silica, and chloride of lime, or common salt, which as it forms a bath
more or less homogeneous or chemically agreeing with the nature of the 2
glass itself, gives beneficial results, provided the process is not pushed
too far, the object not being to make a new chemical compound, but to
arrive most readily at a mixture which will anneal the glass most
rapidly and effectually without injuring it.
Twelfthly. As glass so amicaled may be applied to a variety of 3
purposes that glass as ordinarily prepared cannot from its fragility be
applied in making chemical vessels, dinner and other plates and dishes,
tea cups and saucers, tea and coffee pots, and cooking utensils, moulds,
and spoons of it, I apply glass to the manufacture of all articles now
made in carthenware and of porcelain, thus substituting a much cleaner, 3
wholesomer, and cheaper article not requiring the extra cost of baking,
glazing, and firing. All theso can be mado of beautiful colors and

page_text: patterns by means of presses and otherwise. Tobacco pipes and their
bowls so made would be far more cleanly and beautiful. I also apply
glass so prepared for electrical purposes, for making sounding boards
for pianos and other instruments, to the manufacture of flutes,
clarinets, and other musical instruments, as well as for organ pipes and
harmonium and other musical sound producing tongues, and for the
supports and bearings of engines, and in short in all places where
resistance combined with a smooth surface is required; to the making of
watch cases, and for lenses, and glass for optical purposes, which I mako
by pressure by preference in iron or steel moulds.
Thirteenthly. In placing the sheet and other glass in the bath where
it cannot be conveniently packed with the substance forming the bath
as in the case of metallic alloys, the iron tank with the glass in it is
gradually heated, and the material composing the bath is then poured in,
observing that the glass must previously be heated hot enough to
prevent its cracking, where the specific gravity of the bath is greater
than that of the glass the former is prevented from rising by having a
metal covering secured over it; this cover may be made of iron bars or of
pierced metal. When the metal composing the alloy is disposed to
solidify it is run off by a tap below, and other hot fluids are run in as
oil or the soap mixtures or salts which take the place of the metal, and
admit of its being cooled gradually and of its easy removal.
Fourteenthly. In arranging the tanks for the baths, one at a lower
level than another, so that the bottom of the first shall be higher than
the top of the second and so on in succession, so that the contents of the
higher ones may be removed successively to the lower ones without
trouble, the lowest one being emptied into a reservoir tank whence it is
raised to the highest or removed altogether as is deemed advisable.
Fifteenthly. In quenching heated glass in oils and other fluids above
described cooled down by freezing mixtures. This if desired may be
again fused, worked up, and annealed as above described in order to
obtain a finer quality.
Sixteenthly. In the novel application of by preference unglazed
vitreous earthenware or porcelain, as marbles, or balls, or otherwise, for
the stoppers of bottles for containing olastic fluids, these being of a
nature not to adhere to the bottle while being annealed. I further
adapt as a bottle fastener a tapered plug with a flat knob at its thickest

page_text: end, and a small round knob at the thinner end; this I make either of a
glass harder than the bottle or of unglazed earthenware or porcelain. This
is introduced by pressure into the neck of say, a soda water bottle while.
hot, the neck is then simply pressed closer so as to prevent its return
after it has passed through. When annealed the taper end of the plug is
caused to protrude from the neck by turning the bottle upside down,
and a vulcanised india-rubber ring is passed on to it, which is held in
position by the flat knob, and a circular hollow made at the thickest
end, the elastic fluid presses the plug together with the india-rubber ring
against the neck tight, while the small end protruding beyond the neck
enables it to be pressed down and thus discharge the liquid; I also
adapt wooden plugs similarly shaped which are pressed so as to bo
contracted, and thus to pass easily into the cold bottles; these when
moistened expand so as not to be able to fall out, and on these I apply
vulcanised india-rubber rings in the same manner.
:
Seventeenthly. I further inclose manufactured glass hot or cold, only
not so hot as to adhere or lose shape, in tanks of iron, with powdered clay
or any other suitable material, which I hermetically close with a suitable
cover, the joints of which I clay up, the object here being to keep
out external air, and I thus anneal the glass by heat from suitable
furnaces or by the flame derived from the gas of hydrocarbons generally
actuated by either an ordinary blast or by a steam blower; I also pack
the glass layer by layer in tanks well closed in very hot sand or in other
suitable material. The sand acting as a slow conductor of heat and
retaining it a long time causes the annealing to be performed very
gradually without the necessity of applying other heat.
In explanation I make the following few general remarks:-The glass
maker has various ingredients from which to choose and can make his
own selection for annealing, but in practice in a general way oil or
grease mixed with a caustic alkali, or linseed oil mixed with litharge on
the one hand, and chloride of calcium or other simple salts diluted more
or less with water on the other, or simple hot sand or clay left to cool
gradually will answer his purpose, the metallic alloys being reserved for
special cases. Neither the litharge nor alkali must be in excess, but be
first mixed with the oil and grease so as to either saponify it on the one
hand or to thicken it on the other. The glass furnaces in uso now will
serve equally well, and all that is necessary is to have the iron or other
tanks for the baths arranged so as to be heated with furnaces

page_text: beneath them; as the gradual cooling process is more important than the
gradual heating, it is admissible to immerse glass while hot in a hot
fluid bath, but the heat must be kept up and the cooling be gradual, as
in the ordinary annealing processes.
While on the one hand I disclaim knowingly to make use of the
Inventions of others, I claim my improvements in the manufacture and
annealing and novel application of glass, and in the means and
apparatus necessary to carry the same into effect, as above substantially
set forth.
In witness whereof, I, the said Edward Henry Cradock Monckton,
have hereunto set my hand and seal, this Fourteenth day of
September, in the year of our Lord One thousand eight hundred