Chapter XVIII: Appendix: II

GLOSSARY

=Alumina, or Oxide of Aluminium=, is one of the most abundant of
earths. Combined with silica it is the chief constituent of
kaolins and China clays. It imparts refractory qualities to
clays and is an indispensable ingredient of pure glazes. Pure
alumina or calcined Aluminium is a chemical product.

=Ammonia.=--A volatile gaseous matter, found in some clays.
Alkaline in action.

=Antimony.=--A silver-white metallic element, used with other
oxides as a colourant or to give opacity in glazes.

=Arsenic.=--A non-metallic volatile element, used in glaze making.

=Barytes.=--A heavy spar used with clays to introduce density and
vitrescence.

=Bauxite.=--A very aluminous earth, used in preparation of pure
alumina and to render clays refractory.

=Boracic Acid.=--The natural and, usually, impure product (boric
acid being free from chemicals).

=Borax.=--The combined chemical product of soda and boracic acid.
Used as a strong flux in glazes.

=Calcined Bones.=--The residuum of burned bones, used to stiffen
artificial porcelain.

=Calcined Kaolin.=--Kaolin after it has been subjected to heat to
drive off the water combined with it.

=Calcium Carbonate (Whiting).=--Found as a white rock, and ground
to pure powder. Used with clays for soft bodies. Gives
durability to glazes.

=Calcium Oxide (Lime).=--A widely distributed earthy matter.
Imparts fusibility to clays, in nearly all of which it is
present in varying proportions.

=Chrome, Oxide of.=--Used in making greens, browns, and blacks.
Stands a high fire.

CLAYS:

=Ball Clay.=--Blue and black. Very plastic clays. Used with
non-plastic materials, such as flint, stone, felspar, or
whiting, to form fine earthenwares.

=Cane and Red Clays.=--Clays coloured by the presence of ferric
oxide, and used extensively for bricks, terra-cotta tiles, and
common pottery.

=China Clay.=--A yellowish-white, non-vitreous clay, product of
the decomposition of granitic or felspathic rocks. Cornish China
clay is exceptionally white, pure, and plastic. It is widely
used with China, or Cornwall stone and calcined bones, to make
bone porcelain. Felspar is added to render it vitreous. Mixed
with ball clays, pipe clays, flint, and stone, it makes the
various classes of earthen and stone wares.

=Pipe Clay.=--A very white, smooth clay. Less plastic than ball
clays. Much used for making slips, engobes, and enamels.

=Saggar Clays or Fire Clays.=--Coarse refractory clays
strengthened by the addition of grog, used for saggars, fire
tiles, and bricks.

=Cobalt Oxide.=--The oxide of the steel-grey hard metal. Extremely
valuable in pottery, making all shades of blue for under-glaze
printing or staining. With iron or copper gives blue-greens.

=Copper, Oxides of, and Carbonate.=--Red, green, and black oxides
of copper have been of the utmost value to potters. They are
used to produce green, blue, turquoise, red, and crimson. Its
extraordinary changes in reducing or oxidizing fires are of the
greatest interest to the experimenter.

=Cornish or China Stone.=--A rock composed of felspar and quartz.
Its vitrification (about 1400° C.) imparts hardness and density
to China clays. It is a valuable constituent of glazes. First
known as "moorstone" or "growan."

=Earthy Colourants.=--Rarely used in modern commercial pottery,
except for salt-glazed jars, crocks, and peasant pottery.

=Felspar.=--A fusible rock found almost pure or in combination
with potash and soda, the greater the percentage of alkalies the
more fusible being the spar. It is used to replace more
refractory materials in clay and to stiffen glazes.

=Flint.=--A pure silica with slight traces of calcium. Found in
pebble form on seashores. Calcined and ground to a white powder,
it is widely used to impart whiteness and strength to clays.
Invaluable for bedding and packing in kilns. Used with the
fluxes,--lead, borax, potash, and soda,--to make glazes and
glass.

=Fluorspar.=--A combination of fluorine and calcium, more fusible
than felspar, and of a white colour, felspar being pink.

=Galena.=--Lead sulphide, a highly poisonous material used on
"peasant" pottery, giving a soft, yellowish, transparent glaze.

=Gold.=--Used in solution for delicate purples and lustres.

=Gypsum.=--When calcined gypsum becomes plaster of Paris, these
two materials, together with the allied marble, limestone, and
alabaster, are widely used in pastes (such as Parian), slips,
engobes, and variously to impart fusibility or colour properties
to glazes.

=Iron, Oxides of.=--Have a wide range of colour, from yellow to
purple. They are used to stain glazes and colour bodies. They
impart fusibility to clays and are carefully excluded from fine
white bodies.

=Kaolin.=--A fine, white, very pure, and infusible China clay,
almost pure alumina and silica. Chiefly used in the manufacture
of porcelain and fine earthenware.

=Lead (Oxides and Carbonates of). White Lead, Red Lead,
Litharge.=--Are very widely used as a safe and cheap flux.
Poisonous. It cannot be used in those glazes that have to stand
a high fire.

=Lime.= (_See_ =Calcium=.)

=Lynn Sand.= (_See_ =Quartz Sand=.)

=Magnesia.=--A white metallic element present in small quantities
in most clays.

=Manganese.=--The black and brown oxides of this hard metal are
much used to stain slips and bodies, and to colour glazes brown
or purple.

=Marls.=--Amorphous deposits of lime, sand, and clay, very coarse
in texture. Used in making saggars, drain pipes, and similar
appliances.

=Nickel.=--A hard metallic element, the oxides of which are found
useful in preparing blacks, greys, and greens.

=Nitre or Potassium Nitrate, or Saltpetre.=--A vitreous and
aqueous compound, used in some glazes.

=Plaster of Paris.= (_See_ =Gypsum=.)

=Potash.=--Potassium carbonate or the leached ashes of plants.
Used from earliest times as a powerful alkaline flux.

=Potash, Bichromate of.=--Used for pinks and crystalline effects.
Poisonous.

=Quartz or Quartz Sand.=--Like Lynn or silver sand. This mineral
is pure silica and free from lime, although the sands may
contain some small percentage of iron. Used much like flint for
bedding or with alkaline fluxes for the finest glazes.

=Rutile. Oxide of Titanium.=--Used variously to impart a yellow
tinge to porcelain, and colour and irregularity to some glazes.

=Salt.=--Sodium chloride. Sometimes used in glazes, but best known
in connection with salt glazing. It vaporizes at about 1200° C.,
forming a silicate or hard, thin skin of glaze over the clay.

=Silica.=--A hard, colourless crystalline element; found pure, as
in quartz, or in combination with alumina and alkalies, as in
all clays. Present in all glazes.

=Soda. Sodium Carbonate.=--Product of the decomposition of salts
with acids. It is a strong alkaline flux and much used in glaze
and glass-making.

=Silver Sand.= (_See_ =Quartz=.)

=Tin, Oxide of.=--Used from the earliest times to impart opacity
to glazes.

=Tincal.= (_See_ =Borax=.)

=Titanium.= (_See_ =Rutile=.)

=Whitening.= (_See_ =Lime=.)

=Zinc, Oxide of.=--A white metallic oxide; used to brighten and
stabilize glazes and colours.

POTTER'S TERMS

=Bags.=--Chimneys or walls of fire bricks built to protect the
ware from flame.

=Baitings.=--The feed of fuel during firing.

=Bat.=--Any flat slab of plaster, biscuit, or fire clay.

=Biscuit.=--The fired but unglazed clay.

=Blowing.=--The shattering of the clay shape when biscuiting.
Usually due to hurried firing or the sudden access of heat, and
the consequent generation of steam.

=Blunger.=--A machine for mixing clay.

=Bungs.=--Piles of filled saggars.

=Chuck or Chum.=--The cone or cap used to support shapes during
turning on the lathe.

=Clamming.=--The wet marl, sand, or siftings applied to cracks in
the hatches or doors of kilns to retain the heat during firing.

=Craze.=--The minute cracks that appear in a badly fitting glaze.
When arrived at by design, as in some Chinese work, it is termed
a crackle, but there is then no fissure.

=Drawing.=--Unpacking the kiln after firing.

=Engobe.=--A dip or outer covering of slip; usually applied to
inferior bodies to improve their appearance.

=Fat.=--Clays that are sticky or greasy are sometimes termed fat
by potters.

=Fettle.=--To touch up, and remove traces of seams, cast lines,
etc.

=Fluxes.=--Those materials which by their addition to paste or
glaze render them fusible, although they may not always be
fusible themselves.

=Glost.=--The glazed ware, usually applied to the glaze in firing,
as glost-oven.

=Green.=--The clay shapes before biscuiting.

=Jigger.=--The wheel on which shapes are moulded with the aid of a
jolley or profile.

=Joggle.=--The natch or key in a mould to insure correct
adjustment and prevent slipping.

=Lawn.=--The fine mesh gauze through which glazes are strained.

=Long.=--A clay is termed long if very ductile and tenacious.

=Muffle.=--Usually the fire-clay box or interior of a small kiln,
but applied to any kiln to the inside of which the flames have
no access.

=Natch.= (_See_ =Joggle=.)

=Oxidizing.=--The ordinary method of firing gives an atmosphere in
which there is always sufficient oxygen to consume all the
carbon or combustible gases. If oxygen is present in excess, it
causes reactions known as oxidizing.

=Pitchers.=--Finely ground biscuit. Added to some clays to
increase refractories or porosity. Moulds made in such clays and
fired are termed pitcher moulds.

=Potsherds.=--Any broken biscuit or pot, sometimes used for
pitchers.

=Potting.=--A colloquialism used to designate the ceramic
industry.

=Pugging.=--The roll of infusible clay placed between each saggar
when building bungs.

=Reducing.=--The reaction that accompanies the introduction of
smoke or gas containing carbon in a very finely divided state
into a kiln during the process of firing glaze. Reduction is now
widely employed in obtaining fine lustre effects.

=Refractory.=--Hard, infusible.

=Rich.=--Used of clays that are long and fusible, such as red
clays.

=Riffle.=--A grooved and toothed plaster tool of steel.

=Saggars.=--Or seggers. The fire-clay receptacles in which the
glazed ware is set during the firing.

=Setters.=--Supports used when packing friable biscuit.

=Short.=--A word used to denote a clay that crumbles or is
difficult to pull up on the wheel.

=Sieve.=--Sometimes called a lawn, more correctly a screen for
clay or slip.

=Slip.=--The sieved clay or paste in creamy liquid condition as
used for slip decoration, engobes, or casting.

=Slub or Slurry.=--Clay mixed with water but not sieved, as with
slip.

=Spy.=--The small hole, kept plugged, through which tests and
cones are observed.

=Stunt.=--Or dunt. To crack or split on cooling.

=Turning.=--The shaving down of the clay shape on a lathe, to
impart lightness and finish.

=U. G.=--Under-glaze (applied to colours).

=Vent.=--A hole to aid the even distribution of fire in a kiln or
to accelerate the cooling off.

=Waster.=--Commercially, a spoiled pot; defective ones are termed
"seconds."

=Wedging.=--The beating or slamming operation usually employed to
expel air or correct inequalities just before clay is used by
the thrower.

=Whirler.=--A circular support pivoting on its centre, used in
casting or banding; similar to a banding wheel, but usually
heavier.

MATERIALS, TERMS, ETC.

C = COMBINING WEIGHT
E = EQUIVALENT WEIGHT
------------------------------------------------+------+--------------
SYMBOL |C OR E| FUSING POINT
------------------------------------------------+------+--------------
Alumina (calcined) Al_{2}O_{3} |C 102}|Very infusible
Alumina (hydrated) Al_{2}O_{3}·3H_{2}O |C 156}|
Aluminium Al |E 27 |627° C.
Ammonia NH_{3} | |Volatile
Antimony Sb |E 120 |432° C.
Antimony oxide SbO | |
Arsenic As |E 75 |500° C.
Barium (metallic Ba |E 137 |Fuses above
element) | | red heat
Barium carbonate BaCO_{3} |C 197 |
Barytes BaSO_{4} |C 233 |Fuses about
| | white heat
Bauxite | |
Bismuth Bi |E 28 |
Borax (crystals) Na_{2}B_{4}O_{7}·10H_{2}O |C 382 |Very fusible
Boric acid (crystals) B_2O_3·3H_2O |C 124 |
Boric acid (dry) B_2O_{3} |C 70 |High fusing
Boron (metallic B |E 11 | point
element) | |
Calcined bones | |Infusible
Calcined kaolin} Al_2O_3 · 2SiO_{2} |C 222 |Very infusible
China clay (fine)} | | slightly
| | vitreous
| | at highest
| | fire
Calcium oxide (lime) CaO |C 56 |Very refractory
| | if alone
| | but fusible
| | with clays
Calcium carbonate CaCO_{3} |C 100 |
China stone} 8SiO_{2}·2Al_{2}O_{3}·K_{2}O| 1379 |1300° C. about
Cornish stone} | |
Chrome oxide Cr_{2}O_{3} |C 79 |
Chromium Ca |E 51 |Above platinum
Cobalt Co |E 59 |1500° C.
Cobalt oxide Co_{2}O_{3} |C 165 |
Cobalt oxide (black) Co_{2}O_{4} |C 240 |
Copper Cu |E 63 |1054°-1084° C.
Copper oxide (black) CuO |C 79.5|
Earthy colourants | |
Ochres | |
Siennas | |
Umbers | |
Felspar 6SiO_{2}·Al_{2}O_{3}·K_{2}O |C 556 |1200°-1300° C.
| | about,
| | according
| | to purity
Flint (calcined) SiO_{2} |C 60 |1830° C. about
Fluorspar CaF_{2} | |Much lower
| | than felspar
Galena (lead sulphide) PbS | |Very fusible
Gold Au |E 147 |1054°-1075° C.
Gypsum (plaster of | |
Paris, if calcined) CaSO_{4}·2H_{2}O |C 172 |
Iron Fe |E 56 |1530°-1600° C.
| | about
Iron oxide Fe_{2}O_{3} |C 160 |
Iridium Ir |E 193 |1950° C. about
Kaolin (see calcined | |
kaolin) Al_{2}O_{3}·2SiO_{2}·2H_{2}O|C 258 |Infusible
Lead (metal) Pb |E 206 |326° C.
Lead carbonate PbCO_{2} | |
Lead, red oxide of Pb_{3}CO_{4} | |
Lime (see calcium oxide | |
or carbonate) CaO | |
Lynn sand (see silver | |
sand) SiO_{2} | |
Magnesia (calcined) MgO |C 40 |430° C.
Magnesia (carbonate) MgO·CO_{2} | |
Manganese, carbonate MnCO_{3} |C 115 |
Manganese (metal) Mn |E 55 |1670° C. about
Manganese oxide (or | |
black) MnO_{2} |C 87 |
Nickel (metal) Ni |E 58 |1427°-1450° C.
Nickel oxide NiO |C 75 |
Nitre KNO_{3} | |
Pearl ash or potash KOH | |
Plaster of Paris | |
(calcined gypsum) CaSO_{4}·1/2H_{2}O |C 145 |
Platinum Pt |E 197 |1710°-1775° C.
Potash, bichromate of K_{2}Cr_{2}O_{7} | |Fuses dull-red
| | heat
Potassium carbonate K_{2}CO_{3} |C 138 |
Potassium oxide K_{2}O |C 94 |
Quartz} SiO_{2} |C 60 |1830° C. about
Quartz sand} | |
Rutile (see titanium) | |
Salt NaCl | |776° C.
Silica SiO_{2} |C 60 |
Silver sand (or quartz | |
sand) SiO_{2} | |
Silver (metal) Ag |E 107 |945°-962° C.
Soda ash (calcined) Na_{2}CO_{3} |C 106 |
Soda crystals Na_{2}CO_{3}·10 H_{2}O |C 286 |
Sodium oxide Na_{2}O |C 62 |
Tincal (see borax) | |
Tin (metal) Sn |E 119 |233° C.
Tin oxide (white) SnO_{2} |C 150 |
Titanium oxide (rutile) TiO_{2} | |Infusible
Uranium (metal) U |E 239 |1800° C. about
Uranium, oxide of U_{3}O_{8} | |
Whitening (see lime | |
carbonate) | |
Zinc (metal) Zn |E 65 |443° C.
Zinc oxide (white) ZnO |C 81 |
------------------------------------------------+------+--------------

SEGER CONES. (STANDARD CONES. ABOUT 10° HIGHER.)

NUMBERS. TURNING POINTS. COLOUR, ETC.

APPROXIMATE
DEGREES OF
COLOUR IN KILN CONE HEAT AT WHICH MATERIALS SUITABLE TO BE
NUMBER CONE TURNS FIRED AT THESE TEMPERATURES
OR BENDS (APPROXIMATE)

_Centigrade_

.022 600°
Commences to .021 650° Soft enamel or over-glaze
show colour .020 670° colours.
.019 690°
.018 710°
Dull red .017 730° Enamels on metals. Fluxes
.016 750° and lustres.
.015 790°
.014 815°
.013 835° Very soft glazes and hard
Red to cherry .012 855° enamel colours. Some
.011 880° lustres. Gilding.
.010 900°
.09 920°
.08 940°
.07 960°
Dull cherry to .06 980° Majolica glazes or coloured
light cherry .05 1000° glazes and stanniferous
.04 1020° or tin glazes.
.03 1040°
.02 1060° Earthenware glazes. Soft
.01 1080° China glazes.
1 1100°
Dark orange to 2 1120° Soft to hard or fine
pale orange 3 1140° earthenware biscuit.
4 1160°
5 1180° Sèvres soft bisque.
6 1200°
7 1230° Vitreous ware. Granite ware.
Yellowish white 8 1250° Salt glaze. Stoneware.
9 1280° English bone porcelain or
10 1300° China biscuit.
White 11 1320°
12 1350°
Intense white 13 1380° German & Chinese porcelain.
14 1410° Sèvres porcelain.
15 1430°
Bluish white {16} 1460°
{17} 1480° Copenhagen porcelain.

To convert temperatures:

Centigrade into Fahrenheit.--Divide by 5, multiply by 9, and add 32.

Fahrenheit into Centigrade.--Subtract 32, divide by 9, and multiply by 5.

MEASURES, WEIGHTS, ETC.

APOTHECARIES

1 grain = .0648 gramme.
20 grains = 1 scruple = 1.296 grammes.
3 scruples = 1 drachm = 3.888 grammes.
8 drachms = 1 ounce = 31.103 grammes.

TROY

1 grain = .0648 gramme.
24 grains = 1 pennyweight = 1.555 grammes.
20 pennyweights = 1 troy ounce = 31.1035 grammes.

AVOIRDUPOIS

16 drams = 1 ounce.
16 ounces = 1 pound.
14 pounds = 1 stone.
28 pounds = 1 quarter.
112 pounds = 1 hundredweight (cwt.).
20 hundredweight = 1 ton (2240 lbs.).

CAPACITY (WET)

1 gill = 1.42 decilitres.
4 gills = 1 pint = .568 litre.
2 pints = 1 quart = 1.136 litres.
4 quarts = 1 gallon = 4.545 litres.
2 gallons = 1 peck = 9.09 litres.
4 pecks = 1 bushel.
8 bushels = 1 quarter.

BOOKS OF REFERENCE

TECHNICAL
Chemistry of Pottery. Langenbeck, Karl.
Chemistry of Pottery. Shaw, Dr. S.
Clays. Occurrences, Properties, and Uses. Ries.
Colouring and Decorating of Ceramic Ware. Brongniart, A.
Ceramic Technology. Binns, C. F.
Notes on the Manufacture of Earthen Ware. Sandeman, E. A.
Notes on Pottery Clays. Fairie, Jas.
Pottery Decoration. Hainbach, R.

TECHNICAL AND HISTORICAL
Leadless Decorative Tiles. Furnival, W. J.
Faience and Mosaic, and other volumes. Furnival, W. J.

MANUAL
Pottery. Lunn, Richard.
Grand Feu Ceramics. D'oat, Taxile.
The Potter's Craft. Binns, C. F.
Practical Keramics for Students. Janvier, C. A.

HISTORICAL AND ARTISTIC
Art of the Old English Potter. Solon, L. V.
Chinese Porcelain. Gulland.
Chinese Porcelain. Monkhouse, Cosmo.
Ceramic Art in Great Britain. Jewitt, L.
History of Pottery and Porcelain. Marryat.
Majolica. Fortnum, C. D. E.
Potters, Their Arts and Crafts. Sparkes and Gandy.
Pottery and Porcelain in the United States (and other volumes).
Barber.
Persian Ceramic Art (and other volumes). Wallis, H.
Illustrated catalogue of the Faience of Persia and Near East.
Burlington Fine Arts Club.

APPLIANCES AND MATERIALS, ETC.

SOLD BY

BALL MILLS. Wengers, Ltd. Eng. (Hanley, Stoke
on Trent.)

Abbey Engineering Co. 220 Broadway,
N. Y. City, U. S. A.

BISCUIT SHAPES. Hirshberg Art Co. Baltimore, Md.

{CHINA AND BALL. Mandle and Sant. East Liverpool,
Ohio, U. S. A.

{CHINA AND MODELING. Stewart & Co. N. Y. City, U. S. A.

CLAYS { Wengers. Hanley, Great Britain.

{MODELLING AND Western Stoneware Co. Monmouth,
{STONEWARE Ill., U. S. A.

{SAGGAR AND STONEWARE. W. H. Cutter, Woodbridge, N. J.,
U. S. A.

CONES. Wengers, Ltd. Hanley, Eng.

Drackenfeld & Co. Murray St., N. Y.
City, U. S. A.

Professor Ed. Orton. Columbus, Ohio.

GLAZES. Wengers, Ltd. Hanley, Eng.

Drackenfeld & Co. Murray St., N. Y.
City, U. S. A.

Roessler, Haslacher Chemical Co.
William St., N. Y. City, U. S. A.

KILNS. GAS. Fletcher, Russell. Warrington, Eng.

KILNS. GAS AND OIL. Bellevue Perfection. Detroit, Mich.,
U. S. A.

KILNS. OIL. Caulkins Revelation. Detroit, Mich.,
U. S. A.

KILNS. TRIAL. Wengers. Hanley, Eng.

LAWNS AND SIEVES. Drackenfeld & Co. 50 Murray St.,
N. Y. City.

A. Sartorious & Co. Murray St., N. Y.
City.

Wengers. Hanley Staffs, Eng.

PLASTER. Wengers. Hanley, Eng.

Drackenfeld & Co. N. Y. City.

Calvin Thompkins. Battery Pl., N. Y.
City.

QUARTZ, FLINT, FELSPAR. Wengers, Ltd. Hanley, Eng.

Drackenfeld & Co. Murray St., N. Y.
City, U. S. A.

Golding & Sons. Trenton, N. J.,
U. S. A.

SCALES. Wengers. Hanley Staffs, Eng.

Hy. Troemner. Philadelphia, Pa.,
U. S. A.

STILTS, ETC. Trenton Stilt & Spur Co. Trenton,
N. J., U. S. A.

Wengers. Hanley, Eng.

U. G. COLOURS, ETC. Wengers. Eng.

Drackenfeld & Co. N. Y. City, U. S. A.

WHEELS. Crossley Mfg. Co. Trenton, N. J.,
U. S. A.

T. S. Nickerson. Newburyport, Mass.,
U. S. A.

* * * * *

TRANSCRIBER'S AMENDMENTS

Transcriber's Note: Blank pages have been deleted. On pages that remain, some unnecessary page numbers may have been deleted when they fall in the middle of lists. Some illustrations may have been moved. When the author's preference can be determined, we have rendered consistent on a per-word-pair basis the hyphenation or spacing of such pairs when repeated in the same grammatical context. The publisher's inadvertent omissions of important punctuation have been corrected.

The following list indicates any additional changes. The page number represents that of the original publication and applies in this etext except for illustrations since they may have been moved.

Page Change

20 the highest fire (around 17000°[1700°] Centigrade).
91 but it is [a] waste of time to attempt it
181 The slip is allowed to settled[settle] and the water siphoned off.
193 AL[Al]_2O_3 · 2SiO_{2}
193 Cobalt | C_{6}[Co]
194 Felspar |6SiO_{2}·Al_{2}O_{3}·K^{2}O[K_{2}O]

* * * * *