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Demco, Inc. 38-293 


Courtesy of United States Glass Co. 
Forming the Stem of a Goblet (upper) 
Finished Goblet Ready for Annealing (lower) 





Editorial Staff, Dry Goods Economist; formerly Instructor in 

Merchandise, New York City Department Stores, Texas 

State University, and New York University 



Editor of Series; formerly Director of Department Store Courses, 

New York University; Chairman of Committee on Merchandise 

Courses for New York City Public Schools; Educational Director, 

Department Store Education Association 



Copyright, 1918, by 

Copyright, 1922, by 


All rights reserved 

Veriest fe 2ebttate& 

to Mrs. Henry Ollesheimer, Miss 
Virginia Potter, and Miss Anne 
Morgan, who desiring to give 
greater opportunity for advance 
ment to commercial employees and 
believing that all business efficiency 
must rest upon a solid foundation 
of training and education gave 
years of enthusiastic service to the 
testing of this belief. 




Formerly Director of Department Store Courses, New York 

University; Chairman of Committee on Merchandise Courses 

for New York City Public Schools; Educational Director, 

Department Store Education Association 



Professor of Commerce and Industry, Head of Department 
of Management, and formerly Director of Training School 
for Teachers of Retail Selling, New York University ; 
formerly Educational Director, the National Commercial 
Gas Association 


As "Department Store Merchandise Manuals" these 
books were originally written for salespeople and were 
designed to give them reliable information concerning 
the sources and manufacturing processes of the mer 
chandise which they handle. When it was necessary 
to deal with scientific or historical material it was 
treated as simply and concretely as possible and the 
point of view taken was that of business rather than 
that of the school or laboratory. In this form they 
have proved their practical value not only to the de 
partment store salesperson but in the specialty shop. 
It has been pointed out, however, that the material has 
a wider scope than that of sales manuals alone. 

As reference books, librarians will find the short, 
clear statements and full indexes invaluable. 

As an encyclopaedia of merchandise the series con 
tains scientific information in a simple, compact form 
which makes it available for children and others to 
whom the subjects treated are unfamiliar. 

As textbooks they are adapted for use in commercial 
schools, high schools, night schools, settlement classes, 
and by teachers of household arts and domestic science. 


As source books for practical story-telling, kin'der- 
gartners, primary and vacation school teachers will 
find in them an abundance of interesting material for 
short "true" stories on the various industries and crafts, 
the manufacture of household articles, such as pins 
and needles, as well as the making of pottery, glass, and 
steel. These manuals contain just the material often 
hunted for in vain by teachers and librarians. 

As household helps and shopping guides the young 
housekeeper will find the manuals her best friends be 
cause they not only describe the manufacturing pro 
cesses but tell her how to distinguish well-made articles 
of good materials from the inferior and badly made. 
They also tell her how to care for the clothing or 
household goods which she has bought. 

For salespeople and storekeepers they supply the 
general and specific information about their merchan 
dise which is indispensable to efficiency, yet very 
hard to gather from the scattered sources upon which 
they now depend. 

These changes should enlarge the usefulness of the 
manuals without losing any of their specific value in 
the field of salesmanship. 

We wish to express our grateful appreciation to the 
manufacturers and experts who have given us such 
valuable counsel and cordial co-operation. 



Glass is among the major forms of merchandise. 
It enters into so many of the articles commonly used 
in the household that it is practically an indispensable 
material. In table and kitchenware, in toilet articles 
and in ornaments, for mirrors and for windows, glass 
is found to be either the best substance for the purpose, 
or in many cases the only one that will serve. A 
knowledge of its sources, manufacture, and qualities 
is as valuable and interesting as a knowledge of textiles. 
If one is buying or selling glass, such knowledge is 
necessary for efficiency, but the student of chemistry, 
electricity, or applied science, and the artistic craftsman 
will find it equally important in his work. 

In order to touch upon some of the uses of glass 
outside of the Glassware Department, but of prime 
importance and interest to the student and general 
reader, a section devoted to lamps, windows, stained 
glass, and optical glass has been added. 

The authors are indebted to Mr. Frank E. Freese 
of the United States Glass Co. for reviewing the sec 
tion on manufacture of glass; to Mr. E. W. Bryce, 


Superintendent of Factory B, United States Glass Co., 
for valuable notes on manufacture ; to Mr. A. Douglas 
Xash, Secretary, Treasurer, and Assistant Manager 
of the Tiffany Jfurnaces, for reviewing the chapter on 
Tiffany glass and contributing the section on peacock 
glass ; to C. Dorflinger & Sons and to Mr. G. M. Jaques 
of The Crockery and Glass Journal for reviewing the 
parts on tableware and cut glass ; to L. Solomon &: Son 
for reviewing the chapter on silver deposit ware; to 
Mr. Howard J. Wilbert of the Pittsburgh Art Glass 
Co. and to Mr. Charles J. Connick of Boston, for 
most valuable assistance and criticism and for the 
illustrations of windows and stained glass; and to 
Mr. E. Y. Davidson, of the Macbeth-Evans Glass Co., 
for reviewing the chapter on "Lamps and Lampshades" 
and adding the material on daylight glass. 

For illustrations thanks are due to C. Dorflinger 
& Sons, United States Glass Co., A. Gredelue, and 
to Pittsburgh Art Glass Co. 





Effective Display 

Divisions of the Glassware Department 

Characteristics of Glass 






Nature and Composition 

Difference Between Precious Stones and Glass 

Materials of Which Glass Is Composed 


Occurrence of Sand 

Quality of Sand Depends on Constituents 

Sand Beds 




Kelp or Seaweed 



American Potash 




Chile Saltpeter 

Lead and Lime 

Forms of Lead Used 



Kinds of Lime Used 
Other Materials Used 
Coloring Materials 


Careful Preparation of Materials 

Preparation of the Sand 

Mixing the Batch 

Fusing and Fining 

Glass Furnaces 

Careful Construction of Furnaces 


Pot Furnaces 

Fire Clay 

Manufacture of Pots 

Tank Furnaces 

Calcar Furnace 

Fusing Process 

Fining Process 


Removing Molten Glass from the Furnace 

Methods of Shaping Gathered Glass 


How a Glassblower Works 

Pressing Glass 

Pressed Glass Used in Imitations 



Process of Annealing 

Varieties of Kilns 


Defects in Glass 

Differences in Glass 


GLASS ... 47 


Blown Bottles 

Molded Bottles 

The Owens Automatic Bottle Machine 

Glass for Insulation 

Bullet-Proof and Safety Glass 

Colored Glass 






Designing and Cutting 
Tracing the Design 
Cutting Wheels 
Expert Knowledge Required 
* Roughing 

Figured Blank Glass 
Acid Polishing 
Glass-Cutting Machines 
How to Judge Values 

Differences Between English and American Glass 
Cut Rock Crystal 
Genuine Rock Crystal 
Works of Art Carved from Rock Crystal 

Methods of Decoration 
Sand-Blast Etching 

VIII TABLEWARE ....,..... 7* 


Shaping Stemware 

Variety of Shapes 

Stem Variations 


Sets for Many Purposes 

Single Articles 






Amalgam Mirrors 

Silvered Mirrors 

Platinum Mirrors 

Plateaux or Table Reflectors 

Ancient Mirrors 


Fundamentals of Design * 

Importance of Shape 

Shapes of Cut Glass and Blown Glass Articles 

Purpose for Which Article Is to be Used 

Designs for Cut Glass 

Standard Cut Glass Patterns 

Engraved Glass Patterns 

Laws of Design 

Elements of Design 

Good Design 

The Use of Color in Design 


Possibilities of Glass 

Colored Decoration of Glass Surfaces 


Gold Resist 

Gold Banding 


Painting and Enameling 

Lacquering or Japanning 

Silver Deposit Glass 

Process of Manufacture of Silver Deposit Ware 

Sketching the Pattern 




Engraving the Silver Deposit 

Original Process 


Meaning of the Term "Art Glass" 
Colored Glass 
Flashed Glass 


Beauty of Design and Coloring in Venetian Glass 


Curious Shapes 

Process of Formation 

Filigree Glass 

Cameo Glass 

Mosaic Glass 

Frosted Glass 

Laticella Glass 

Millefiori Glass 

Coloring of Venetian Glass 

Bohemian Glass 

Methods of Ornamentation 

History of Bohemian Glass 


Old Industry Revived 

Window Glass 

Peacock Glass 


Characteristic Colors of Tiffany Favrile Glass 


Table Vases 
Ornamental Vases 
Glass Candlesticks 


The Lamp Department 


Types of Oil Lamps 

Adjustable Lamps 

Lamp Chimneys 

Lamp Stands 







Candlesticks and Candelabra 

Lighting Fixtures 
Indirect Lighting 
Semi-Indirect Lighting 
Daylight Glass 
History of Lamps 


Requirements of Optical Glass 

Veins or Striae 

Furnaces and Crucibles 



Jena .Glass 

American Optical Glass 

Lens-Grinding ^ 

Lenses and Prisms 

Laboratory Glass 


Kinds of Glass Used in Windows 
Window Glazing 
Double-Hung Windows 
Casement Windows 
French Windows 
English Casement Windows 
Leaded Lights 

Kinds of Glass Used in Leaded Lights 
History of Window Glass 
Stained Glass 
Enamel-Painted Windows 
Opalescent Windows 
Antique Glass Windows 
Antique Glass 

Reproductions of Antique Glass 
The Making of Stained Glass Windows 
Silver Stain 

Effect of the Finished Window 
Stained Glass Design 






Wonders of Glass-Making 

Glassmakers of Egypt 

Theban Works of Art 

Glass of Other Oriental Countries 

Assyrian Workmanship 

Persian Glassware 

Characteristics of Grecian Glass 

Roman Glass 

Varieties of Glassware 

Glass of Pompeii and Herculaneum 

Varieties of Bottles 

Other Glassware 

Venetian Glass 

Murano a Famous Glass Center 

Development of Art in Other Countries 

Spanish Glass 

Bohemian Glass 

Other Varieties 

Early Art in France 

English Glass 

Growth of the Glass Industry in England 

Characteristics of English Glass 



Early Experiments 
Pioneer Glass-Making Concerns 
Growth of the Industry 
Pressed Glassware 
Pressed Lime Glass 
Invasion of Foreign Markets 
The Owens Bottle Machine 
Improvements in Furnaces 
In the Middle West 


Qualifications for Selling Glass 



Other Points of Importance to Customers 





Things to be Avoided 




Books for Reference 


Forming the Stem of a Goblet Frontispiece 

Finished Goblet Ready for Annealing .... Frontispiece 


1. Open Pot for Glass-Melting (on page) 26 

2. Covered Pot for Glass-Melting (on page) 26 

3. Diagram of a Furnace with a Horseshoe Flame . . . 

(on page) 30 

4. Rolling Glass on Marver . . , 36 

5. The Evolution of a Tumbler (on page) 37 

6. Cutting Glass . 56 

7. Cut Glass Goblet in Poppy Design 62 

8. Patterns in Miter Cutting 86 

9. Examples of Venetian Glassware 112 

10. Example of Bohemian Engraved Glass ...... 114 

11. Leaded Glass 156 

12. Stained Glass Window 170 

13. Examples of Roman Molded Glass 178 

14. Ancient Venetian Glass Furnace 182 

15. Ancient Glassmakers' Tools (on page) 183 


Chapter I 


Effective Display 

One of the most beautiful and effective displays of 
the modern store is found in the Glassware Depart 
ment. It is sometimes situated where the natural light 
is strong; but more often it is lighted artificially with an 
arrangement of mirrors and reflectors to give the most 
brilliant and dazzling effect. 

Glassware is placed on glass shelves often mir 
rors with mirror backgrounds on polished tables, or 
on velvet or felt. Sets are arranged on mirror pla 
teaux which give them a double reflection. 

Colored glass is grouped harmoniously ; a few pieces 
are often introduced among the crystal to heighten 
the beauty of each by contrast. The decorations in 


gold, silver, and enamel are brilliant and glistening and 
add to the effect of splendor. 

Divisions of the Glassware Department 

There are usually three general divisions of the 
Glassware Department : 

1. Tableware 

2. Toilet sets 

3. Decorative or art glass 

Sometimes a division is made between the domestic 
and the imported glass; but the American glass is so 
excellent in quality that there is no need for such a 

Glass is also divided according to its composition, 

Flint, lead, or crystal glass 
Lime or lime-crystal glass 
Common or bottle-glass 

Manufacturers are known as flint or lime manufac 
turers, according to the kind of glass they produce. 

Cut glass is made of lead or flint glass and is some 
times called cut rock crystal ; pressed or molded glass 
is lime-crystal- and the cheaper grades may be bottle- 

Glass is also referred to commercially as American, 


Belgian, Bohemian, Swedish, French, or English, in 
dicating the country in which it was made; and in 
other cases it may be referred to by the name o the 

Characteristics of Glass 

Glass is one of the most valuable of all manufac 
tured materials. It has the three most essential quali 





The usefulness of glass is primarily due to its great 
adaptability. As a container of food it is almost per 
fect, as it can be attacked by only one acid and that 
acid is not found in food. It is, however, slightly 
affected by strong alkalies. 

Because of its smooth surface it can be kept clean 
and will not retain odors ; and thus it makes the best 
possible container for liquids, medicines, and nearly 
all chemicals. 

Because of its transparency it is the best material 
for windows, lamp chimneys, shades, and all illumi 
nating fixtures. 

Its use in photography, astronomy, and all the phys- 


ical sciences is unequaled, and it is the one material 
which can preserve and aid the sight. 


The durability of glass is not generally realized. It 
is brittle, of course, and may be fractured by a blow 
or by too sudden expansion or contraction caused by 
sudden applications of heat or cold. On the other 
hand, ordinary usage does not wear it out and the 
atmosphere does not disintegrate it. 

Its durability is largely dependent upon careful an 
nealing, which is one of the finishing processes. 


The transparency and the refraction of light by col 
orless glass makes it beautiful. This beauty may be 
increased by cutting, polishing, and other modes of 
decoration and by the addition of color. The dazzling 
beauty of artistic glass almost equals that of perfect 

Part I Manufacture of Glass 

Chapter II 


Nature and Composition 

Glass is an artificial substance of mineral composi 
tion. It has some of the characteristics of metals and 
some of those of the non-metallic minerals. It re 
sembles metals in that it may be molded or drawn out 
into thin threads or tubes when heated to a certain 
temperature ; but it is far more brittle. When heated, 
glass becomes viscous; that is, in a condition between 
that of a liquid and that of a true solid ; when cool, the 
materials of which it is composed are held together in 
solution but not actually united. 

Under ordinary conditions glass is transparent, 
though it may readily be made so that one cannot see 
through it. It might easily be mistaken for those nat 
ural mineral formations which we call precious stones, 
except that it never crystallizes. 



Difference Between Precious Stones and Glass 

All transparent minerals, and many which are not 
transparent, have a crystalline formation that is, the 
tiny particles of which they are composed are grouped 
in regular geometrical figures. These figures may be 
too small to be seen without a microscope ; but they are 
always there, and it is the reflection of light from these 
tiny particles that makes polished stones used in jew 
elry more beautiful than glass. Glass has none of 
these tiny crystals. 

Materials of Which Glass Is Composed 
Glass contains: 

Sand or silica 


Lead or flint 

Soda or potash 

It may also contain metallic oxides for coloring mat 
ter and frequently other metals, such as aluminum, 
iron, zinc, magnesium, barium, borax, arsenic, and 

Glass containing a number of different materials 
melts at a lower temperature, but is less perfect in 
structure, than that composed of pure silica, lime, and 
soda; or silica, lead, and potash. These materials 
mixed together form what is called the "batch," that 


is, the mixture which, when sufficient heat is applied, 
becomes glass. 


As clay is the main element in all pottery, so is sand 
the essential material in the making of glass. No 
glass can be made without it. It contributes toughness 
and strength to the batch and the viscosity which 
makes it possible to shape the molten glass into proper 

In an elementary class in chemistry, experiments in 
which acids and alkalies combine are often shown 
early in the course. The instructor perhaps pours hy 
drochloric acid into a dish containing soda, and the 
students observe the violent boiling and bubbling that 
follows. This is known as a chemical reaction. 
After things quiet down and evaporation takes place, 
the dish contains a substance neither acid nor soda f but 
a neutral compound formed by the union of the chlorin 
of the acid with the sodium of the soda, which proves 
to be sodium chlorid, or common salt, 

A similar happening takes place in the making of 
glass. An acid is generally thought of as a liquid 
with a sour taste and pungent odor, and it may seem 
an absurd statement to say that sand 5s an acid. Nev 
ertheless from a chemical standpoint the statement is 
true. When the sand is mixed with the soda and lime 


the high temperature of the furnace is all that is 
needed to bring about just such a reaction as occurs 
when hydrochloric acid and soda are brought together. 
The resulting compound, glass, is therefore a neutral 
salt (silicate of sodium and calcium), although its 
properties differ greatly from other salts. 

Occurrence of Sand 

Sand in one of its various forms exists everywhere. 
It is formed by the wearing away of rocks by wind, 
rain, snow, and other forces of nature. It is finally 
deposited in a pure state in sea, river, or lake beds, 
and in a less pure state in the sandy soils of certain 
districts. What is called " sand " may be almost any 
thing from nearly pure silica (sand that is 99.9 per 
cent pure) down to clay marls, a crumbling deposit 
consisting chiefly of clay mixed with limestone, which 
contains very little silica. 

Quality of Sand Depends on Constituents 

The quality of sand is largely determined by the 
amount of other substances it contains, such as com 
pounds of iron, lime, aluminum, and magnesium. If 
pure it is perfectly white and does not effervesce or 
change color when treated with an acid. It is insolu 
ble in all acids except hydrofluoric. 

The value of sand is largely determined by the 


amount of iron it contains, because iron gives glass a 
greenish-yellow or clouded appearance. As nearly all 
sand contains some iron, cobalt or manganese is usually 
added to neutralize the undesirable color. 

The sand used in making the best grades of glass 
ware must be free from impurities, fine, and of uni 
form quality. If the- sand is too coarse it will not 
fuse quickly, and if it is too fine it will melt too rapidly. 

Sand Beds 

The most desirable sand is usually found on the 
seashore or in the beds of rivers or lakes, where the 
grains are ground to a uniform size and shape by the 
constant friction of the water. 

Two famous sources are the Forest of Fontainebleau 
near Paris and Alum Bay in the Isle of Wight. 
Epinal, Belgium, has sand of almost equally pure com 
position. English sands are not of such high quality. 

Most of the sand in the United States is tinged with 
yellow or gray. Practically every state in the Union 
contains sand fit for glass. The most important de 
posits in the country, however, are located in West 
Virginia, Massachusetts, Pennsylvania, and Illinois. 
Sand from the Berkshires in Massachusetts is prac 
tically free from iron, and that from Pennsylvania 
contains less than .01 per cent. The finest quality is 
found l~ West Virginia. The mountains there con- 


tain mines of sand said to be as pure as that from 


Pure sand may be obtained by crushing sandstone, 
but the grains thus obtained are not likely to l>e so 
uniform in size as those from a sand bed, and the 
necessary grinding makes its preparation more expen 
sive and tedious. 


Quartz is crystallized sand. It appears in nature as 
rock crystal, a transparent and colorless variety, and 
also in a number of semiprecious stones, such as the 
amethyst and false topaz. These forms of silica might 
be crushed and used for glass, but their hardness and 
intrinsic value make them too expensive for such use. 
Low-grade quartz is sometimes used. 


Flint is a form of quartz containing lead and potash, 
which appears in certain localities in the form of boul 
ders or large pebbles. It was used very generally by 
the early English glassmakers. The name " flint " is 
still applied to a kind of glass that is soft, brilliant, and 
suitable for cutting. Now, however, this kind of glass 
is usually made from oxide of lead and is more com* 


monly referred to as crystal or lead glass. In France 
these flint pebbles are still gathered on the sea and 
river shores and carried by the peasants to the glass- 

Flint must be finely ground before being used, and 
as this is an expensive and tedious process, it is suit 
able only for the best grade of glassware. 

The various trade terms in use are apt to be some 
what confusing, 

" Lead flint " glass contains : 

Sand or silica 

Oxide of lead 

Potash or pearlash (a special form of potash) 


" Lime flint " glass contains : 

Bicarbonate of soda 

" Strass " is a flint glass with a large amount of 
lead ; it is used for making artificial gems. 

Kelp or Seaweed 

Seaweed and other forms of plant life were at one 
time another source of silica, as the stalks of many 
sea plants, such as kelp, are stiffened with it. Modern 


invention, however, makes it more profitable to utilize 
such sea plants by extracting the potash and soda they 
contain rather than the silica, which may be obtained 
by less expensive methods. 


Next in importance to sand or silica among the con 
stituents of glass are the alkalies, potash and soda. 
They are necessary in order to make the other materi 
als melt and combine and are called " fluxes/' Modern 
glassmakers obtain them from natural deposits and 
prepare them in special factories. Both are found in 
nature in various combinations: chloricls, sulphates, 
carbonates, and nitrates. The forms generally used, 
carbonates and sulphates, are the most desirable from 
the glassmaker's point of view, since they are the pur 
est and of the most uniform composition. 


Pearlash (potassium carbonate) is the form of pot 
ash most commonly used. Crude pearlash is obtained 
from ashes as a by-product of the beet-sugar industry 
and is used for inexpensive glass. Saltpeter (potas 
sium nitrate) is another form valuable for its oxygen 
and alkali. Ancient glass contained potash made from 
seaweed or kelp, but this was inferior to modern pot 
ash because of its impurities. 


Natural deposits of potash were discovered in the 
mines of Strassfurth near the River Elbe in Germany, 
and almost the entire world became dependent on 
them. When war conditions shut off the supply, the 
potash situation became serious. Fortunately for the 
American industry, local fields of kelp were discovered, 
which brought relief for the time, but Germany is still 
the great source of the world's supply. 

American Potash 

A potash mine is being worked in New England, 
where a shaft 1,000 feet deep has been sunk. Night 
and day shifts are working the deposits. It Eas been 
known for a long time that there are considerable pot 
ash deposits in the vicinity, but they were not mined 
to any extent until the cutting off of the European 
supply made the mining of potash in this country 
worth while. 

Large amounts of the compounds of this element 
are present in the vast beds of kelp floating on the 
waves of the Pacific near the western coast. Each 
year the waters of the Pacific coast yield a crop from 
which potash salts possessing a normal value of more 
than $90,000,000 can be readily extracted for use in 
agriculture and the arts. Not only are there inex 
haustible supplies in the waters of the Pacific, but also 
remarkable deposits in the arid waste about Searles 


Lake in California, and in Utah. Beds of kelp have 
also been discovered in the Philippines. 


The general use of soda as a flux is a more recent 
development than the use of potash, though much of 
the glass of ancient times was soda glass. As with 
potash, it was first obtained from the burning of 


Soda-ash (sodium carbonate) is the purest form 
and is used in the better glass works. It is made by 
treating the natural soda deposits with certain chem 


Salt-cake (sodium sulphate) is a cruder form used 
in making bottles and the heavier glassware. It is 
produced in the same manner as soda-ash, 

Chile Saltpeter 

Chile saltpeter (sodium nitrate) is used in the crude 
state or refined for the better ware. The nitrates of 
both soda and potash are valuable for the alkalies they 
contain, but more particularly for the oxygen which 
aids in freeing the batch from bubbles. 


Lead and Lime 

The third necessary ingredient of glass is either lead 
or lime. Lead is used for the best cut glass, because 
of the brilliancy, resonance, and weight which it gives. 
It also lowers the melting point of the batch. 

Forms of Lead Used 

Lead oxide is an expensive material for glass- 
making. Red lead, the form generally used, is of a 
bright red color. It is preferable to other oxides be 
cause it is easily decomposed by heat. It is made by 
roasting metallic lead in furnaces to eliminate the 
impurities present, such as silver, iron, and silica. 
Red lead is very poisonous and the workmen in flint 
glass factories have to wear respirators to keep them 
from inhaling lead dust while they are preparing it. 
In good factories perfect cleanliness is also insisted 
upon so that the lead may not poison the workmen's 

Kinds of Lime Used 

Lime (calcium oxide) is a much less costly mate 
rial. It makes a harder glass than lead, and for this 
reason lime glass is not suitable for cutting. It may 
be used, however, for all kinds of pressed ware and 
for many varieties of art glass where lightness and 
delicacy are desired. Lime adds to the viscosity of 


the molten glass, and so increases the toughness and 
serviceability of the finished product. If used in ex 
cess, it gives the glass a milk-white color. 

Lime is found in many parts of the world, appear 
ing as : 

Limestone rock 

Chalk (calcium carbonate) 

Chalk is a soft, brittle rock which can be easily 
ground into a fine powder. It is often mixed with 
iron, flint, and magnesia, which impair its quality. 

Gypsum (calcium sulphate) is a form of lime less 
pure than limestone, sometimes used in glass-making. 

Other Materials Used 
Other materials added for special purposes are : 







Aluminum is found in small quantities in nearly all 
glass, but a larger percentage is used in opal or optical 

Arsenic acts as a flux and neutralizes certain objec 
tionable colors. 


Barium replaces lead for some purposes of glass- 
making. It is an expensive material. 

Borax adds to the density and brilliancy of glass. 

Magnesia is similar to lime, for which it is some 
times substituted. 

Zinc contributes some of the same qualities that 
soda and potash do. It is used in special optical glass. 

Coloring Materials 

Transparent colored glasses are made by simply 
adding coloring components in relatively small quanti 
ties, to the clear glass batch. These are usually me 
tallic oxides: copper or cobalt for blues; chrome or 
iron for greens; silver or uranium for yellows; and 
gold chlorid or seleniun for ruby. The deep amber 
used for bottles is made by adding carbon with sul 
phur in some form; this is generally coal dust, but 
any of the grains wheat, oats, barley, or even saw 
dust, will make a rich amber color. 

The opaque and semi opaque glasses require the same 
foundation mixture, but other materials in larger pro 
portions are needed to insure sufficient opacity. Some 
of these other materials do not become chemically 
components of the glass, but remain in mechanical sus 
pension only, i.e., floating in fine particles, and tend 
to destroy the uniformity and strength of the glass. 


Others exert a destructive action on the pots or cruci 
bles holding the batch. 

These are some of the reasons why opaque glass 
has not been in more general use for the manufacture 
of hollow wares, but recent progress has been made 
in eliminating or neutralizing the injurious effects of 
the ingredients referred to, and producing a material 
which will stand rough usage. Opaque glass is there 
fore now invading a field which hitherto has belonged 
exclusively to the potter. 

The translucent lighting glass now so much in 
favor, because of its superiority, is crystal glass to 
to which has been added opacifying components, 
the most essential being oxide of aluminum. 

Lead and bismuth are the only metallic oxides which 
can be added to silica and alkali without discoloring 
the batch. Even an excess of lead gives a yellowish 

Owing to the presence of metallic substances in 
nearly all sand used for glass-making, colored glass 
has always been more common than that which is clear 
and colorless. 

Color which is muddy and dull, such as the green or 
the brown tinge of common bottle-glass, is due to the 
use of low-grade materials ; but the colors which may 
be produced by the introduction of carefully prepared 
metallic oxides, which are used with a scientific knowl- 


edge of their effect on the silica and alkali of the 
batch, add the final touch of beauty to decorative glass 
which brings it into the region of the fine arts. The 
further discussion of color therefore belongs in the 
section devoted to art glass. 

Chapter III 


Careful Preparation of Materials 

The quality and the appearance of finished glass 
ware depend upon the purity and fineness of the ma 
terials of which it is made, and the proper propor 
tions of each in the mixture which forms the batch. 
Each material must also be as free as possible from 
water, as moisture hinders the melting process. 

Preparation of the Sand 

Sand for the manufacture of glass is first carefully 
examined under the microscope and analyzed by chem 
ical tests for purity. It is then emptied into recepta 
cles containing a large quantity of clean, pure water, 
moved about vigorously, and allowed to settle. As it 
is heavier than water it naturally falls to the bottom, 
while the particles of foreign matter which float upon 
the top are drawn off with the water. 

The sand is next burned to remove the moisture and 
to destroy any vegetable matter which has not been 
taken out. For this process it is placed on the bed 



r of a moving oven which travels continuously through 

From the oven bed it is dropped into a vault through 
a series of sieves covered with fine copper gauze. 
This sifting process not only removes impurities but 
also aids in procuring a sand with grains of uniform 

The other materials are usually refined and prepared 
before they reach the glass manufacturer. 

Mixing the Batch 

The mixing of glass materials must be done with 
scientific accuracy, as an excess or deficiency of any 
one of them affects the appearance and quality of the 
finished product. Too much sand keeps the batch 
from melting, and too little potash or soda has the 
same result. Too much lime or lead affects the color 
and quality. All coloring compounds must be used 
with a knowledge of their chemical reactions in order 
to produce the proper effect. 

Each formula must therefore be prepared by a 
trained chemist, and every ingredient carefully 
weighed. The formulas for certain kinds of glass 
are secret, and even the workmen are kept in ignorance 
of them lest they should disclose the processes to a 
competing manufacturer. For small batches the 
weighing and mixing are done by hand, but for larger 


quantities by machinery. In the weighing process 
only the ends of the scale beam may be seen by the 
workmen, the exact proportions being known only to 
a few members of the concern. 

After weighing, the materials are all collected in an 
" assembly box " and dumped into a hopper, which 
empties its contents into the mixing machine. This 
machine rotates in various directions while revolving 
steel arms within the mixing chamber stir the contents. 
Samples of the batch are taken out and examined. 
When the sample shows that the whole mass is uni 
form in color and texture, the " cullet " or " frit " is 
added. This is a special mixture of materials in a 
pulverized and half -molten state which hastens the 
process of melting and fusion for which the batch is 
now ready. 

Fusing and Fining 

The fusing of the materials into a uniform molten 
liquid out of which glass articles may be formed is a 
most interesting process. 

After the fusing the next step in the manufacture 
is fining. By means of intense heat and some material 
containing oxygen, impurities and gas bubbles are re 
moved. Both of these important processes are de 
scribed in greater detail in the latter part of the chap 
ter. Both take place in glass furnaces. 


Glass Furnaces 

Three kinds of furnaces are needed in a glass fac 

1. The working furnace, either: 

(a) Pot or crucible furnaces, or 

(b) Tank furnaces 

2. The calcar furnace for making frits 

3. The annealing oven 

The first two kinds are described in this chapter, the 
third in Chapter IV. 

Careful Construction of Furnaces 

Furnaces for making glass must be built with a view 
to durability, regularity, and intensity of heat, and 
also economy of fuel. Since they must resist a tem 
perature of between 1,800 and 2,700 R, glass fur 
naces are constructed of fire-proof bricks made of an 
infusible clay mixed with cement obtained from the 
pulverization of old pots the containers for molten 
glass. The fire of the furnace never goes out until 
the furnace wears out after one or two years of 

Glass furnaces have much in common with pottery 
furnaces except that the heat of the glass furnace is 
more constant. Upon the regularity of its heat de 
pends the safety of the crucibles as well as the quality 


of the glass they contain. Sudden variations of tern* 
perature tend to crack the crucibles and irregular cool 
ing " striates " or streaks the glass. 

The furnace must be constructed so as to resist 
great heat and avoid drafts, and must be very durable. 
The fuel must be as free as possible from impurities, 
and the degree of heat applied and the duration of the 
fusing process must be carefully regulated or the entire 
batch may be wasted. 


The kind and the quality of the fuel used in a glass 
furnace is of importance. Wood was naturally the 
first fuel to be used. It made a clean heat but one of 
slow and uncertain temperature, varying with the kind 
of wood used and with its wet or dry condition. The 
old glassmaker, like the old potter, knew the value of 
the various kinds of woods for his purpose and chose 
them accordingly. 

The use of coal necessitates covering the pots in 
which the glass is melted to prevent the soot and sul 
phur from corning in contact with the glass and thus 
filling it with small particles of harmful matter as well 
as affecting its color. This was a constant annoyance 
to the glassmaker. 

The introduction of the hooded pot necessitated the 
addition of more fluxing material or of more heat to 


make the batch melt, because the hood prevented the 
flame from touching the batch as in the case of open 
pots. The discovery of gas as a fuel solved the prob 
lem for this country. 

The glassmaker of modern times owes much to the 
discovery of natural gas as a fuel. It makes a smoke 
less flame and has scarcely any impurities. It pro 
vides a uniform heat and there is no discoloration from 
smoke. It gives no trouble through the accumulation 
of ashes or dirt. 

The introduction of gas as a fuel has revolutionized 
the whole glass-making industry. In the United 
States both gas and petroleum are used. Even for pot 
furnaces gas is used ; in tank furnaces it is indispensa 
ble. Natural gas is employed wherever it is obtain 
able. Where there is no natural gas, artificial gas is 
made from other fuels. 

Pot Furnaces 

The pot furnace is circular, with a chimney in the 
middle through which the smoke, flame, and heated 
air escape. At the base of this enormous chimney is 
a central fire, and fire bars occupy the middle of the 
furnace floor. On the sides of the furnace are recesses 
in which the workmen stand; and on the inner sides of 
these recesses are openings into the pots or crucibles 


which are placed opposite on a clay stand or shelf 
around the circumference of the furnace. 

Each crucible has one small opening only, near the 
top, in the shape of a neck projecting out through the 
furnace wall. Through this opening the batch is poured 
into the crucible ; during the melting it is tightly sealed 
so as to be practically air-tight, and no direct flame, 
smoke, or heat gets to the fusing glass. Because of 

Figure i. Open Pot for Figure 2. Covered Pot for 

Glass-Melting Glass-Melting 

this protection from outside influences it is possible to 
make glass of greater luster and better color than can 
be made otherwise in the present state of the art. The 
word "color is here used in its technical sense as 
applied to crystal glass. When a glassmaker says his 
glass is of good color, he really means that it is with 
out color, or as nearly so as he can get it. 

A furnace is described as having so many " pots/ 1 
the number of these indicating its size. The pots vaiy 
m shape and capacity. They may be round, oval, or 
rectangular, from 18 inches to 3 feet in height, and 


with open, or " hooded " or domed tops. They may 
hold a few pounds (monkeys), or several tons of 
molten glass. Figure i shows an open pot; Figure a 
a covered one. 

Pots last only a few weeks though it takes months 
to make them. While in use they require the most 
careful attention, as the intense heat widens even the 
smallest crack and soon breaks the pot. This means 
the loss of the entire batch of glass. 

The process of making glass in a pot furnace may be 
more carefully regulated than is the case with other 
processes, because the glass is in comparatively small 
quantities and the molten mass may be kept from con 
tamination by the gases and other impurities always 
present, especially when the fuel is other than natural 
gas. The pot furnace was the one used by the old 
Venetian glassmakers in making their beautiful and 
fragile glass. Pot furnaces of an improved type are 
largely used today in making cut or pressed glass, and 
especially in making optical and colored glass where 
quality is of the first importance. 

Fire Clay 

The pots must be made of a special grade of fire 
clay. An extraordinary amount of care is required in 
the manufacture. 

Fire clays are clays which contain a large amount 


of silica and a small percentage of fluxes or binding 
materials, so that they can withstand a high tempera 
ture. Fire clay is found in nearly every part of the 
United States, especially in New Jersey, Pennsylvania, 
Ohio, and Missouri. The pot clay found near St. 
Louis is said to be unsurpassed even by the most cele 
brated clays of Europe. 

Manufacture of Pots 

When the clay has been finely sifted it is well mixed 
with burnt clay or unglazed fragments of broken pots, 
which tend to bind it together. Skill is required in 
mixing and working the ingredients in order to drive 
out every particle of air which, by expansion in the 
furnace, would break the pots. 

After the mixed material has been made into the 
creamy substance known as " slip/' as if for pottery, 
it is given a definite shape by casting, molding, or 
building. The practice is to make several pots at a 
time so that one may partially set while another is 
being built. The pots are allowed to stand for from 
8 to 12 months in a temperature of from 90 to 1 00 
F. They are then placed on fire clay blocks in a bak 
ing furnace and subjected to a red heat (1,800 to 
2,700 F.) for several weeks. If they do not crack or 
melt at this temperature, they are fit for use. 


In addition to the prolonged heat of the glass fur 
nace, the pots must be able to withstand the corroding 
effects of some of the raw materials in the batch, such 
as red lead, potash, soda, and borax. This corroding 
may even go so far as to make a " specky " glass, 
which is formed by a combination of the aluminum, 
usually found in the pot clay, and the alkaline or metal 
lic ingredients of the batch. To prevent this, the cru 
cible is glazed on the inside. 

Tank Furnaces 

The tank furnace is a square or rectangular oven 
with doors at the ends. It varies in depth from 20 to 
42 inches according to its purpose. 

One end is called the " filling hole " and into this 
the batch is shoveled. The other end is called the 
" working hole " and from it the molten glass is taken 
to be molded. This arrangement permits continuous 
working. The portions of the tank which come in 
contact with the molten material must be made of the 
special grade of fire clay which is used for the pots 
in the pot furnaces. The tank furnace is in reality 
a single open crucible. In practice it is often of large 
dimensions and is never closed nor covered. 

A horseshoe flame (shown in Figure 3) is used in a 
tank furnace and is so regulated that each part of the 
furnace remains at the same temperature during the 


whole time that the furnace is working. The flames 
of the 'fuel play over the melting batch so that the 
fusing is much more rapid and efficient, with a result 
ing economy of fuel. Unfortunately, exposure to the 
atmosphere and the direct contact of the glass with 



Figure 3. Diagram of a Furnace with a Horseshoe Flame 

hot gases in various stages of combustion, make the 
regulation a much more difficult and uncertain matter 
than in the closed pots. 

For making glass of the finest quality, such as that 
for cutting and the best grades of pressed or blown 
wares the pot furnace is best suited. 

The tank furnace, on the other hand, has the ad 
vantage of producing glass of greater uniformity, free 
from cords and streaks, and is therefore well adapted 
for making blown ware such as bottles of all sorts, 
lamp chimneys, glass lamps, thin blown tumblers, etc. 
in fact any or all articles in which clearness is of 
more value than the color tint. Progress is being 


made in the building and manipulating of tanks, and 
it is not unlikely that in the near future this type of 
furnace will produce glass which will in all respects 
equal that made in pots. Glass which is in no respect 
inferior to pot glass is even now being made in tank 
furnaces. This, however, is not through any change 
in furnace construction, but through increased knowl 
edge as to the use of decolorizing materials which, 
when added to the glass batch, neutralize objectionable 

The C tank is a modern type of furnace invented in 
1 86 1 and used largely throughout Europe and America. 
It is made from pot clay and divided into " floating 
compartments," each at a lower level than the one 
immediately before. The raw material is put in at the 
door, and as it melts, flows from the first compartment 
into the second, which is the refining compartment 
Here the temperature is higher and the refining takes 
place. From this compartment the refined liquid 
passes into the gathering compartment, where at a 
lower temperature it cools and thickens for the form 
ing. These furnaces may be worked continuously and 
are in many ways better than the old style of tank 

Calcar Furnace 

The calcar furnace is in the form of an oven about 


10 feet long, 7 feet wide, and 2 feet high, in which 
some of the batch materials are partially melted, form 
ing a pasty mass out of which the moisture and gases 
have been driven. This mass is allowed to solidify, 
and while yet soft is cut into squares, which are stored 
for use as frit or cullet (See page 22.) When these 
frits are mixed with the batch they hasten the process 
of fusion. 

Fusing Process 

In the case of a tank furnace the batch is put in 
through openings in the melting end by means of long- 
handled shovels or some mechanical device, and new 
material is added every half-hour for four or more 

When pot furnaces are to be filled, the pots must 
first be entirely emptied and the temperature of the 
furnace brought up to 2,500 F. before the new ma 
terial is put in, since a low or an unequal temperature 
has a disastrous effect on the batch. 

As in the case of any boiling liquid, allowance must 
be made in each pot for the bubbling up of the boiling 
mass so that the pots may not overflow and cause the 
loss of valuable material. As they boil down, fresh 
material is added; four to eight fillings are custom 


Fining Process 

The batch has now become a mass of foaming, seeth 
ing, molten glass. Gradually it changes to a viscous 
and entirely transparent substance full of gas bubbles. 
As any bubbles in the finished glass are an obvious 
defect, however, their removal has been provided for 
by putting into the batch some materials containing 
oxygen. The heat of the furnace is increased until 
this oxygen is freed and forms large bubbles, which 
rise to the stirface and carry the smaller ones with 
them. This is called the fining process. The more 
liquid the mass is, the more readily will the gas bubbles 
disengage themselves. For this purpose " fluxes " 
substances which promote the chemical action just de 
scribed are added. The glassmaker sometimes uses 
arsenic or a substance containing moisture, such as 
a potato attached to a rod. 

When the fining process is completed, the melter 
takes out samples or proofs of the liquid on a rod or a 
long spoon and examines them for bubbles. If im 
purities have gathered the surface is also skimmed. 

The melting and fining process takes about 24 hours. 
Then the temperature of the furnace is lowered to 
working heat and the shaping and working of the 
glass is begun. 

Chapter IV 


Removing Molten Glass from the Furnace 

Molten glass, as has been said before, is not liquid 
but viscous; as it cools it passes to the solid form 
without crystallization and while cooling can be shaped 
according to the glassrnaker's will. While in this 
semiliquid condition glass has the malleability and duc 
tility which metal has, that is, it may be hammered or 
rolled without cracking, and it may be drawn out into 
a wire. The glassmaker speaks of the molten glass as 
" metal/' 

There are three methods of removing it from the pot 
or tank : 




Gathering is the process of removing a part of the 
mass by twisting it around the end of a long tube. It 
is the method employed in making all blown glass and 
much of the molded and pressed ware. Gathering re- 



quires great skill, and makes an admirable display of 
dexterity. Like the art of juggling, it can be learned 
properly only in early youth. 

Ladling is the process of transferring the molten 
glass to large tables by means of long ladles. 

Pouring is done by machinery which lifts and tips 
the heavy pots so that the glass flows out. 

Methods of Shaping Gathered Glass 

The glass obtained from the pot by gathering is 
shaped or formed by : 



Blowing is the most primitive and characteristic way 
of forming glass. Formerly all glass, even that for 
window panes, was shaped entirely by this process. 
It is the method still used to form the blanks for the 
best cut glass and for all pieces of delicate design. 

The glassblower's tools are: 

Blowing iron or blowpipe 
Working rod 
" Battledore " 
Glass blowpipe 




Tongs and similar pronged wooden tools 

Measuring stick and compass 

Spring balance 

The most important tools in the process of blowing 
are the blowpipe and working rod. 

The blowing iron or blowpipe is a long hollow iron 
rod varying in length from 5 to 6 feet and in diameter 
from % to 2 inches, according to the weight of glass 
to be gathered. 

The working rod is a light, tapering rod of solid iron 
varying much in both length and strength. It is used 
to hold the vessel in the last stages of manipulation. 

The " battledore " is used to flatten the square bot 
toms of tumblers or other vessels ; the glass blowpipe in 
expanding the opened end of bulbs ; the shears in re 
moving surplus glass, or cutting the ends of handles 
or rods; the pincers in shaping the handles of jugs or 
the decorative filigree work on vases ; tongs and simi 
lar pronged wooden instruments in handling and open 
ing up certain pieces ; the measuring stick and the com 
pass for marking with wax the amount of surplus glass 
to be removed with the shears ; the spring balance in 
comparing the weight of each vessel with that of its 

C<wrtesy of United StatcH Glass Co. 
Figure 4. Rolling Glass on Marver 



A " marver," or table upon which the glass may be 
rolled about while it is being shaped, completes the 

How a Glassblower Works 

The blower gathers a mass of the viscous glass from 
the pot on the end of his iron blowing pipe, adding 

Figure 5. The Evolution of a Tumbler 

more and more as it cools until he has the amount 
necessary for the article he wishes to make. 

By rolling or marvering the ball over the polished 
surface of the table just referred to, he makes it uni 
form in shape and free from bubbles. Figure 4 shows 
this operation. 

He then inflates the mass by blowing air into it 
through the tube, also exposing it from time to time 


to the heat of the furnace, which further expands the 
air until the article is enlarged as much as he wishes. 

Figure 5 shows the various stages in the making of 
a tumbler. The flat bottom is shaped by pressing the 
lower end of the elongated bulb of glass on the marver. 

The process of glass-blowing is fascinating to watch. 
The shapeless mass is twirled, pulled, and thrown 
about with perfect control and ease until it assumes its 
final, beautiful shape. We are accustomed to think of 
glass as so fragile that it can be handled only with 
great care and this makes the glassblower's work seem 
almost magical. 

The blowing of glass by the breath may have been 
originally suggested by the bubbles which appear in 
the molten glass. It was evidently practiced in Egypt, 
for Egyptian monuments as early as 2000 B. c. show 
glassblowers working with their pipes. 

The blowing was done entirely by the breath until 
1824 when M. Robinet of the Baccarat factory in 
vented the Robinet pump, by the aid of which large 
cylinders could be made. . This gave rise to the com 
pressed air and automatic blowing machines which do 
much of the work today. 

Pressing Glass 

The metal for pressed glass is gathered on a solid 
iron rod from 4 to 6 feet long, called a " ptuity." The 


punty is thicker at one end to allow a good hand-grip, 
and forged at the other end into the shape of a knob. 
The worker heats this knob, dips it into the molten 
glass, and by twisting it covers it with a layer of glass, 
which he manipulates into the shape of a ball, and cools 
until it is nearly solid. The ball of glass is called 
the " moil," and is made larger or smaller according 
to the amount of glass to be gathered. 

The gatherer now inserts the punty into the pot 
mouth, dips the moil into the liquid glass, and begins 
a rotary movement, slowly at first, then with greatly 
accelerated speed literally gathering up the glass, until 
he has the needed amount suspended in a droplike 
fashion beyond the end of the punty. He then carries, 
or rather juggles, the ball of liquid glass to the con 
veniently placed press, and drops it deftly into the 
mold. Another worker, the presser, severs the con 
necting thread between the body of glass and the 
punty with a pair of scissors. 

Molds for pressed ware are usually made of cast 
iron, and are simply matrices of the size and shape of 
the article to be made, marked with any pattern which 
is desired for the outside of the article. A plunger, 
forced into the mold by a lever operated by hand or 
machine, shapes the inside of the article. The molds 
must be constructed to admit of a ready removal of 
the pressed article. They are, therefore, either of 


one solid piece of iron, from which the article can be 
dropped out by turning it over ; or they are made oi a 
number of sections jointed and hinged together. The 
latter sort are used for shaping the more complex 
forms of glassware or those ornamented with deep de 
signs, as, for instance, an imitation of cut glass. 

The temperature of mold and plunger is carefully 
regulated by streams of air blown against them; 
otherwise the surface of the glass might be cracked or 

When the glass has hardened the plunger is removed 
and the shaped article is taken from the mold It 
must be smoothed on the inside to remove the rough 
ness made by the plunger and if marks of the mold are 
left, plain pieces are reheated in the " glory hole/' as 
the side openings into the furnace are called. 

Pressed Glass Used in Imitations 

Pressed glass is made to imitate cut glass and the old 
hand-carved art glass of Venice or Bohemia. 
There are three ways of telling an imitation : 

1. The angles of the design in the imitation are 

blunt and rounded instead of being clean cut 
and sharp. 

2. The design is very symmetrical and usually com 



3. The glass lacks the brilliancy given by the 
processes of hand-cutting and hand-polish 

Molding is a combination of the blowing and press 
ing processes. 


A mass of molten glass is gathered from the cru 
cible on the end of the blowpipe. After being mar- 
vered and slightly expanded it is thrust into the mold, 
which shapes the outside while continued blowing 
forms the inside. Molded glass differs from pressed 
glass in the fineness of its finish, as it is partly a hand- 

Molds are of many shapes and may be of complex 
construction. They may be of two, three, or more 
separate pieces hinged together so that the molded 
article may be easily removed. 

They are made of cast iron or other metals, plaster 
of Paris, clay, or wood. The metal molds are 
strongest, but the metal is apt to discolor the glass. 
This difficulty is met by lining the molds with wood or 
carbon. Cork-lined molds are sometimes used to give 
blown ware a uniform shape and size. 

Figure 13 in Chapter XVIII shows four old Roman 
molded glass pieces. 



After the glass articles have been formed and cooled, 
it is necessary to subject them to a process known as 

Annealing is the reheating and cooling of the formed 
glass, and is one of the most important operations in 
glass-making, since it is this process which makes it 
resistent to blows and changes of temperature. Glass 
ware which is not properly annealed is very fragile 
and easily broken. Annealing also adds to the bril 
liancy of the glass. 

Process of Annealing 

The glass articles are placed in annealing kilns or 
ovens (often known as "lehrs"), and heated to a 
temperature of 800 R The heat is gradually raised 
to 1,200 F. and then gradually lowered, so that the 
articles cool slowly. It is this gradual cooling which 
makes the glass strong, durable, and of uniform and 
consistent texture, since the pores, expanded by the 
heat, are allowed to contract evenly throughout the 
entire substance. When cooled quickly the surface 
shrinks more rapidly than the inside and therefore is 
under a greater strain. 

Large heavy pieces require a longer time and greater 
heat than small thin pieces. The time may vary from 
a few hours to a week. 


Varieties of Kilns 

Ordinary kilns or ovens are used for heavier articles, 
such as blanks for cutting and plate glass, which must 
remain in the kiln for a considerable length of time. 

The continuous lehr or kiln is used for lighter arti 
cles. This style of annealing oven has a long rectan 
gular chamber or tunnel of brick heated at one end and 
provided with numerous small iron trays or trucks, 
which are moved by an endless chain. The pieces of 
glass are placed on the trays at the hot end and grad 
ually moved towards the cooler part of the oven, mak 
ing room for fresh pieces. 

The labor required for piling up and taking down 
the glass in a kiln is saved by using this continuous 

The famous Murano glass works (see Chapter 
XVIII) had a simple arrangement for annealing, con 
sisting of a tunnel about thirty feet long, which was 
heated by the waste heat from the melting furnace. 
It had a tramway running down the center with mov 
able trucks, on which the glass was drawn from one end 
to the other. * 

The intermittent kiln or oven is heated by gas and 
fitted with a shelf on which the glass is set. When 
filled with ware it is closed, heated, and allowed to 
cool; the process is controlled by carefully regulated 


A novel method of annealing was invented by a 
Frenchman named De la Bastie. The pieces were 
put in a wire frame while yet soft and immersed in a 
hot liquid, preferably mutton fat. For various reasons 
the process was not very successful and did not dis 
place the annealing oven. 


Much of the beauty of glass is due to its brilliancy 
and the reflection of light from its polished surface. A 
natural polish is produced by the processes of fusing 
and annealing, but in cut glass this is destroyed by the 
action of the water and sand on the cutting wheels. 
Polishing is an important feature of the glass-cutting 

Pressed glass is dulled by coming in contact with 
the sides of the metal molds, which chill the surface too 
quickly. This luster may be restored by placing the 
piece in the " glory hole/ 7 where it is held in an intense 
flame, which gives it what is known as fire polish, 

Old glassmakers reheated their glass many times, 
since each period of heating and cooling added to its 

Today the acid polish, described in Chapter VI, is 
given to the better grades of pressed glass and to all 
but the finest cut glass. 


Defects in Glass 

If the materials of which glass is made are impure 
or improperly combined, the color will be poor; for 
instance, an excess of iron will give a greenish or a 
brown tinge. Too much manganese gives a pink 

" Bottle glass," which is used for the cheaper grades 
of bottles, is colored by the iron and other impurities 
which it contains. 

Glassmakers have trade terms for defective glass, 
'such as: 

" Seedy " glass, which contains small air bubbles 
caused by too rapid melting or too low tem 
perature in the furnace. 

" Stony " glass, which contains tiny lumps of un- 
dissolved material or clay from the sides of pots 
or tanks. 

" Cordy " or wavy glass, with waves or streaks of, 
crystallized glass instead of a clear, even tex 

" High color " is the pink tinge from manganese. 

" Low color " is the green tinge from iron. 

Glass may be imperfectly formed or it may be poorly 

Cut glass should not be cut too deeply and the edges, 


while clear and sharp to the eye, should not be knife- 
edged or rough to handle. 

Differences in Glass 

Lead glass is heavier and more brilliant than lime 
glass, but the difference is not always apparent to the 
untrained buyer or salesperson. 

Pressed glass has a dull finish as the result of the 
chilling given the hot molten glass, or " metal/' as it 
is called, by the mold. This may be removed by re 
heating, and the " fire polish " is restored to all good 
pressed glass. 

Colored or decorated glass is subject to many acci 
dents in fusing or firing the color. 

Defective articles are usually discarded by the manu 
facturer to be sold as seconds, or, if too imperfect, to be 
remelted and formed again. 

Chapter V 



Bottles were among the earliest forms of glass ves 
sels, and bottle-making is still a special division of the 

They are: 

1. Blown and shaped by hand. 

2. Molded. 

3. Blown and pressed by automatic machines. 

Bottles made entirely by hand are now found only in 
art glass or among articles of luxury. Even finely cut 
bottles are usually molded. 

Blown Bottles 

For blown bottles the process is as described in 
Chapter IV. The molten glass is gathered on the blow 
pipe, rolled or marvered on the flat metal plate, and 
blown with the breath until it is nearly the required 
size. During the process the pipe is swung gently to 



and fro, so that the glass settles downward, leaving a 
thinner part next the pipe to form the neck. It is then 
reheated and is either blown into a mold of fire clay or 
metal, or shaped by hand tools. If there is to be a con 
cave bottom, as in wine bottles, this is made by pushing 
up the hot glass by means of an iron rod called a pontil, 
upon which a small mass of glass has been gathered. 

The bottle is now attached to both the pontil and the 
pipe, but by chilling the glass the pipe is broken off at 
the point where the neck is to end. The neck is heated 
to make it smooth, and a thread of glass is wound 
round it to give the proper stiffness and finish. 

By various inventions machinery has been substi 
tuted for each of these processes in bottle-making. 

Molded Bottles 

The first change consisted in operating the mold by 
a lever, one-half of the mold being attached to the 
floor and the other raised by the workman by means 
of a rod. This mold gave the bottle its final shape. 

By another machine the glass is gathered on an iron 
rod and dropped into a measuring mold, which assures 
the right quantity. This material is then forced into 
a neck mold, which gives the shape of the neck of a 
bottle. While the neck mold is still firmly attached a 
plunger is forced down through the material and then 
by means of compressed air the lower part of the 


bottle is blown out to the proper length and fitted into 
a third mold, called the finishing mold. Levers open 
the finishing and neck molds at the same time and re 
lease the perfect bottle. This machine is capable of 
producing 120 bottles per hour. 

The Owens Automatic Bottle Machine 

The automatic machine takes the place of human 
hands and requires no skilled workmen at all. A fur 
nace is built with revolving pots, in front of which 
the machine is placed. As the pots revolve, the 
machine, driven by an electric motor, moves with them. 
It has either six or ten arms carrying " blanks " and 
finishing molds. As each blank mold passes over the 
pot the molten glass is sucked up into it by a vacuum 
process, which is regulated to supply just the right 
quantity for the bottle required. The neck is formed 
while the glass is in this first mold. 

Then the blank mold opens and the glass is shown 
as a white-hot cylinder supported by the neck; the 
finishing mold rises and closes over it and the shape is 
finished by the application of compressed air. After 
making a complete turn the machine drops out the fin 
ished bottle, which is put into the tempering ovens and 
travels slowly towards the cool end, where it is ready 
to be packed and shipped. 

The regularity of the mechanical process and the 


even pressure of the air produce bottles of a uniform 
strength and quality. 

Glass for Insulation 

As glass is a non-conductor of electricity and a very 
poor conductor of heat it is the best material for insula 
tion. Telephone and telegraph wires are wound on 
glass caps to prevent the loss or transference of the 
electricity. The recent shortage of timber in Europe 
has occasioned the use of telegraph poles which have 
a frame work of woven wire in the center but are 
otherwise made entirely of glass. These poles will 
neither rot, rust, nor be destroyed by insects and are 
therefore worth a greater original cost. 

Spun glass is used as insulating material m electrical 
ovens, which will retain their heat for a long time 
after the current has been cut off, 

Bullet-Proof and Safety Glass 

One of the greatest objections to the commercial 
use of glass is its brittleness, which not only causes it 
to break easily but to splinter and fly under mechanical 
shock and cause very serious accidents. 

Bullet-proof glass was invented for war use and 
various forms of safety glass are made in a way that 
prevents this splintering. The glass is made in two thin 
sheets with a layer of transparent, shock-resisting 


material between, and the three layers are fused into 
a solid sheet. The adhesion is so perfect that it looks 
like ordinary glass but when struck with great force 
it will only crack. The splinters are held by the bind 
ing material and cannot fly off. Safety glass is chiefly 
used for wind-shields, headlights, and lenses for auto 
mobiles and for goggles. During the war gas-mask 
lenses, aviators' goggles, and aeroplane wind-shields 
were made of it. 

Wire glass is an older material made on the same 
principle. A wire mesh is inserted between two layers 
of rolled plate for use in the windows of factories, 
gymnasiums, etc., where it is subject to jarring or 
striking, and also as a protection against fire. The 
metal, however, affects the transparency of the glass 
as well as being itself quite visible, while the binding 
material in safety glass is not. 

Colored Glass 

Mosaics are composed of glass with the addition 
of various mineral compounds. The glass is melted 
and mixed with colored powders until it becomes a 
thick mass. Then the mass is slowly baked until it 
has reached the required degree of hardness, when it 
is taken out and molded into small cubes, or "palettes." 

In making a mosaic picture the artist sketches the 
design with charcoal on a slab of plaster. Small holes 


are hollowed out with a piercer and the mosaic cubes 
are chipped to fit in the holes where they are held by 
means of a glue or cement. 

In the city of Lyons glass pavements have been 
recently laid. They are composed of "ceramo crystal," 
a devitrified glass in blocks 8 inches square. This is a 
return to the mosaic glass pavements used by the 


Colored glass is used for many other purposes, useful 
and decorative. Among the former is the use of ruby, 
green, and purple glass for signaling purposes in rail 
ways, motor cars, and lighthouses. Photography also 
makes extensive use of colored light for various pur 
poses, and medical science and beauty doctors require 
colored light. 

Part II Cut Glass and Tableware 

Chapter VI 



There are three grades of glass which are known 
as cut glass. The best grade is cut entirely by hand; 
the second grade is first pressed and then finished by 
hand; the third is merely pressed in patterns which 
imitate cut glass. 

Genuine cut glass has four characteristics known to 
the expert. These are : 

1. Its color a clear, brilliant white tinged with 

steely blue 

2. Its bell-like resonance when struck 

3. Its weight 

4. Its fine finish 

These characteristics depend upon the materials of 
which it is made and also upon the process of manu 
facture. A well-known manufacturer recently gave 
the following definition : " Cut glass is and always 



has been a piece of crystal cut on wheels. The design 
is cut in, not pressed in, nor blown in ; and it is polished 
by hand. Genuine cut glass is not then partly re 
touched, pressed lime glass." 

An authority on testing cut glass says : " First note 
that the article is really cut. This can be detected by 
the sharp edges of the design as well as by the delicacy 
and intricacy of the design itself. Second, tap with a 
pencil. If the glass contains lead, a necessary ingre 
dient of all good cut glass, it will resound like the ring 
of a deep-toned, silvery bell." 


The materials from which genuine cut glass or cut 
crystal is made are : 

Silica or pure sand 
Oxide of lead 

About 60 pounds of lead are used for each 100 
pounds of silica; the lead gives weight, resonance, and 
brilliancy and also keeps the glass soft for cutting. 
The potash is used to clarify the glass and to add to the 
scintillating effect. All the materials must be pure. 

The earlier stages of the process are the same as for 


blown glass, that is, making the blank, the rough shape 
resembling the general outlines of the piece to be 
copied, includes : 

Gathering the material 
Blowing into shape 

There are certain differences. The roughly shaped 
" blank " is heated three times and worked over by 
three different workmen. In the annealing oven the 
glass is brought to a particularly high temperature and 
is cooled very gradually* 

The blanks for cut glass are blown much thicker 
than for articles which are not to be cut, particularly 
if the piece is large and the incision must be deep. 
Some pieces lose over one-third of their original 
weight during the cutting process. 

Designing and Cutting 

The second part of the process is quite different It 
includes. : 

Tracing the outline of the design 
Cutting fine lines 
The shaped blanks are stored on the shelves of the 


factory in which the cutting is to be done. Each large 
glass-cutting establishment employs its own artists, 
who design both the shapes and the decorations of its 
pieces. The designs must be mathematically accurate 
and suited to the spaces they are to occupy. 

Tracing the Design 

First the design is outlined with a brush in red lead 
and turpentine, or transferred from a stencil or a cop 
perplate pattern. 

Cutting Wheels 

Glass is cut on wheels made both of steel and of 
stone. These wheels may vary in diameter from i% 
inches to 3 feet, and in thickness from % of an inch to 
i inch. They are driven by steam, gas, or electrical 
power. The larger wheels are used for cutting 
straight lines and the smaller ones for curved lines, 
The sharper the curve, the smaller must be the wheel 
The face of the wheel may be round, square, or 
pointed. As many as fifteen or twenty different kinds 
of wheels of different degrees of hardness are used in 
the cutting process. Figure 6 shows the cutting room 
in a glass factory. 

An expensive and novel form of cut glass is made 
by stone engraving, a form of cutting done entirely 
by hand with stone wheels and copper tools. The de- 


signs are chiefly vines and flowers and are not cut deep. 
This is sometimes mistaken for pressed glass. 

Expert Knowledge Required 

Glass cutters must be expert workmen, as their 
material is heavy and yet easily broken and mistakes 
can seldom be corrected. The operator holds the blank 
against the wheel with just the right amount of pres 
sure for the speed of the wheel ; the vibration of the 
glass will cause it to crack, unless skilfully handled. 
The operator judges the proper pressure by feeling as 
much as by sight. 

Elaborate pieces require several weeks for cutting 
and polishing and the labor cost is very heavy. 


The " roughers " are workmen who make a rough 
outline of the design, following the larger lines and 
cutting the deep incisions. This is done on steel wheels 
about 2% feet in diameter. A steel wheel is also used 
to make the bottom of the piece level. In some cases a 
wheel of carboniferous sandstone is used instead of 

As the wheel cuts into the glass, a stream of water 
and sand made from garnet and hornblende trickles 
over it from a can suspended above. This stream of 
water and sand assists the cutting and makes it almost 


noiseless. When the process is finished, the glass has 
a frosted or milky appearance. 


When the deep lines have been cut, the design is re 
fined and smoothed upon a wheel of black cragleith 
stone without the use of sand or emery. Cragleith is 
a famous stone from Edinburgh which contains no 
sand. The stone wheel, which resembles the steel one 
in size and shape, smooths the deep incisions and gives 
the glass a gray, satiny finish which enables it to take 
a high polish. 

Another stone which is used in the process is called 
alundum, an artificial composition of a special kind of 
clay called bauxite. The clay has been subjected to 
an electrical current, reduced to crystals, crushed to 
powder, and then mixed with sand, salt, and sawdust, 
and burned in a kiln. 

The piece now goes back to the stencil operators, 
usually girls, who put in the design for the finer cut 
ting the stars, checkerworkr, light criss-cross lines, 
etc. This cutting is done on a stone wheel and re 
quires great skill and accuracy. 


After the complete design has been cut, the piece is 
taken to the polisher, who manipulates a wooden wheel 


charged with emery or rouge, a polishing material. 
This process removes all roughness and polishes both 
the cut and the uncut surface. Sometimes a hard fiber 
brush is used or a cork wheel and powdered pumice- 
stone. To give a high gloss the buffing wheel is used 
a sort of pad made of pressed wool. It is covered 
first with pumice-stone and water and then with putty 
powder, both of which give a brilliant polish. 

Figured Blank Glass 

The next grade of " cut " glass is far less expensive. 

It is known as the " figured " blank glass, because 
while it is made of the same materials as the genuine 
crystal, the process is simpler. The molten glass is 
blown into a mold, which not only gives it the desired 
shape but leaves the design upon it. 

The design is then sharpened and finished upon a 
wheel and the glass is polished with acid. The best 
lime blanks are treated in the same way. 

Lime is much cheaper than lead. It makes a harder 
glass and one that is lighter in weight, but without the 
crystal white color, brilliancy, or clear metallic ring of 
the lead-potash glass. The lime blanks, moreover, are 
usually only partly cut; the heavier parts of the design 
having been pressed in and the piece merely finished off 
by hand. Lime-crystal blanks, however, when made 
of fine materials and carefully finished, produce a glass 


of fine quality at about half the cost of lead glass. 
Trade names, such as " semicut," or " floral-cut," are 
given to lime blanks, which may be partly cut or only 

The inferior imitation is of ordinary bottle glass 
made of inferior and impure materials, and merely 
pressed into designs which resemble cut glass. Both 
kinds of imitation cut glass are polished with acid 
rather than by hand. 

Acid Polishing 

The glass is carefully washed in soap and water, 
dried, and brushed on the inside with melted paraffin. 
It is then dipped three times into a vessel filled with 
hydrofluoric acid, which eats away the sharp edges and 
gives it brilliancy. After the wax has been removed, 
the piece is again washed with a pure soap, wiped with 
a linen towel, and wrapped in silver tissue paper ready 
for shipping. 

Genuine cut glass with careful handling retains both 
its brilliancy and color, but glass made with lime and 
soda is not only less brilliant than lead-potash glass 
when it is first made, but if the materials are impure it 
darkens with age. 

The acid polish is quick and clean, but it produces a 
wavy appearance and a peculiar hard sheen instead of 
the smooth, deep brilliance produced by friction on 


wooden, felt, and cork wheels. Glass finished by acid 
polish is also more quickly clouded by moisture in the 
air and must be cleaned more often. 

Glass-Cutting Machines 

Glass-cutting machines have recently been invented 
which will make still another distinction, in addition to 
the hand-cut, partly cut, and pressed ware. These 
machines have not been used long enough, however, to 
judge of their effect on the market. 

How to Judge Values 

In judging of the value of any hand-made product 
as compared with one made by machine, there are 
always two things to be considered : 

1. The real beauty, individuality, finish, and du 

rability of the hand-made article. 

2. A " collector's value," due to the fact that hand 

made articles are more costly to make and 
therefore can be in the possession of only a 
few fortunate persons. 

Both of these considerations are important in the 
case of cut glass. The luster, finish, and durability 
of hand-cut lead blanks are all greater than in any of 
the imitations. This beauty is partly dependent on the 
designs, which differ widely in their effectiveness. 


Differences Between English and American Glass 

Nearly all the English patterns are what are called 
straight or miter cuts, that is, the lines are straight 
rather than curved. They consist of : 




Hobnail, or blunt-cornered diamonds 



Strawberry diamonds 


Figure 8 in Chapter X shows several examples of 
miter cuttings. 

The best English glass is called rock crystal, because 
of its resemblance to the clear sparkling stone of that 

American cut glass is considered by some judges the 
best in the world and has been exported to Europe for 
a good many years ; though for a long time merchants 
in this country were afraid to acknowledge that it was 
of domestic manufacture and therefore called it im 

Fan scallops, rosettes, curved and floral patterns 
have been developed recently as the result of American 

'Courtesy of C. Dorflinger & bons 
Figure 7. Cut Glass Goblet in Poppy Design 


Popular floral patterns are the : 
Scotch thistle 
Rambler rose 

A combination of miter and floral patterns is often 
seen, in which the sides of a piece are miter-cut and 
the bottom decorated with a floral pattern. The miter 
patterns may be pressed and the flowers cut with a 
" mat " or frosted finish which gives the piece individ 

Floral cutting is much more delicate and graceful 
than the stiff miter cutting, though the latter is very 
effective in large, heavy pieces. The deeper cuts are 
brilliant, but the lighter ones are easier to keep clean. 

Figure 7 illustrates a beautiful example of floral 
cutting a goblet cut in poppy design. 

Cut Rock Crystal 

Cut rock crystal is a very beautiful form of cut 
glass which has the shimmering luster and wavelike 
appearance of moving water instead of the brilliancy 
of more familiar types. It is an excellent copy of the 


genuine rock crystal which is so rare that it is seldom 
found except in the cabinets of collectors. 

The cutting is in fine, delicate, floral patterns which 
resemble the tracing of engraving. 

Genuine Rock Crystal 

A brief description has already been given of rock 
crystal. It is a colorless, transparent form of quartz or 
crystallized silica. It looks like a brilliant and beauti 
ful form of glass, but differs from it in being crystal 
lized. It was first found in Europe in the highest 
peaks of the Alps Mountains, and for many centuries 
was supposed to be ice frozen so hard that it could not 
be thawed. 

Works of Art Carved from Rock Crystal 

The Romans carved cups and vases of rock crystal, 
some of them of remarkable size, but it was used more 
generally in the middle ages. Altar crosses and other 
church ornaments were made from it, and it adorned 
the palaces of kings. In 1351 the throne and the foot 
stool of a French king were made of the clear, spark 
ling crystal, and Catherine de Medici had a collection 
of magnificent vases of the same material. Some of 
these treasures are set with precious stones and in- 
crusted with gold and silver* 

Rock crystal is very durable and much less easily 


scratched than glass. It has sometimes been sold as a 
diamond when cut like a gem. While it is still used in 
rings and pendants in some countries of the far east, 
it is usually found in larger pieces and ornamented 
with beautiful carving. The merchants of Venice 
probably introduced it to western Europe. It was 
found later in the Italian and the French Alps, and also 
in Hungary, Iceland, and Madagascar. The United 
States is now the principal source of supply. 

Crystal carving is closely allied to the work of the 
goldsmith, and has been associated with the cutting 
of cameos and semiprecious stones. Though it often 
appears in large vessels, most of these pieces are 
composed of several smaller fragments joined together 
by gold or silver. Some magnificent specimens, how 
ever, are carved out of a single piece with no orna 
ment except the exquisite handiwork. 

There are very fine collections of rock crystal in 
Paris, Dresden, Vienna, Berlin, London, and Madrid. 
The J. P. Morgan collection, formerly at the Metro 
politan Museum in New York City, and the Altaian 
collection have been considered the finest in this 

Chapter VII 


Methods of Decoration 

The surface of glass may also be decorated by 
means of friction by cutting instruments. These 
forms of decoration are known as : 


Etching 1 


Carving or Embossing 



Engraving is hand-work ; the design is either cut out 
by a copper disc operated by foot-power or machinery 
or else by rapidly revolving spindles. The glass is 
held against the disc or the spindle by the operator's 
hands. Engraving is usually a line design, but elab 
orate scenes can be sketched by means of the spindles, 
as in the case of Bohemian glass. The depth and 



width of the lines can be varied by changing the disc 
or the spindle. 


Etching is done by means of hydrofluoric acid, the 
only acid which will attack glass. The piece of glass 
to be etched is covered with some substance called the 
"resist," on which the acid has no effect. The sub 
stances commonly used for the purpose are beeswax, 
paraffin, tallow, resin, rubber compounds, and metallic 
lead. Beeswax is quite expensive but very satisfac 
tory because it melts easily and may be applied with 
a brush, and because it is also easily removed. 

The two processes employed are : 



For needle- or machine-etching small needles are ar 
ranged in moving arms, which pierce through the resist 
and outline the pattern on the glass. The machines 
are operated by electricity or by compressed air. The 
article is then immersed in hydrofluoric acid, which 
instantly attacks the uncovered glass. Needle-etched 
designs are always symmetrical a series of straight or 
zigzag lines, circles, curves, etc. 



This method allows much greater freedom of design, 
but it also requires skilled labor and is therefore more 
expensive. The design is first cut in a metal plate and 
then 'a print is taken from the plate on tissue paper. 
From the tissue paper print it is transferred to the 
glass, which is then coated with the resist around all 
of the design. 

After the acid has eaten out the pattern, the wax is 
removed by placing the article in boiling water and 
steam. Ten distinct processes are required for plate- 
etching, but beautiful results may be obtained, 

Sand-Blast Etching 

In this species of etching the design is cut by means 
of streams of sand, which are blown against the glass 
by compressed air or steam. The process was invented 
in 1876 by a Philaclelphian, who conceived the idea 
from the dulling of lighthouse glass by the sand blown 
against it in times of storm. 

The glass is prepared as for acid-etching, the sur 
face being covered with a resist such as rubber, resin, 
tallow, or even tinfoil or paper out of which the design 
is cut. The stream of sand is then applied and grad 
ually cuts away the glass, leaving a dull or frosted sur 
face. The effect is varied by using wet instead of dry 
sand, and by varying the degrees of fineness. The 


finer the sand and the less the pressure of the blast, the 
more delicate the design. Sharp sand gives the best 
result. Seashore sand is ineffective, as its cutting 
edges have been worn away by the constant action of 
the water. 


Frosting is now done either by acid or the sand-blast,* 
but was originally produced by rolling the piece in 
finely powdered glass while it was still soft enough to 
receive a thin coating of the glistening particles. 
Frosted glass was first produced in Bohemia, where it 
was designed to imitate 'the coating made on glass by 
frost in winter. The designs were therefore more like 
a delicate lace-work than a definite pattern. The Ve 
netians made frosted glass in beautiful colors, but they 
were never so appropriate as the white frost-work. 


The design is roughly outlined on the glass with 
acid and then cut away with small steel gravers. It 
is very delicate work, requiring a rather soft glass and 
most careful manipulation of the tools, which are either 
operated entirely by hand or struck lightly with 
wooden mallets. 


This process is the reverse of etching in that the 


designs are raised on the glass. The resist is made to 
cover the design. When the background, left exposed, 
has been eaten away by acid, the design is left standing 
out in relief. The designs are usually large, simple, 
and conventional. 


Designs may be applied to the glass when it is in the 
viscous state by fusing fresh pieces on it instead of 
cutting into the surface. This is called "trailing/ 1 as 
the design is usually worked out in trails of vines or 
similar figures. It is one of the ways of applying color 
and is much used in Venetian glass. 

Chapter VIII 


The largest division of table glass is stemware 
which includes sherbet and grapefruit glasses, com 
potes, all forms of drinking glasses except tumblers, 
and many larger pieces for holding fruits or desserts. 


Stemware comprises those articles which consist of 
a bowl, stem, and foot or base. The relative size of 
the bowl and foot is determined by certain rules of 
proportion ; for instance, the foot must be neither too 
small nor too large to look well and give the glass 
a proper balance. The stem may be so short that it is 
scarcely more than a curve between the two larger por 
tions, or it may hold the bowl high in the air. 

The finer grades of stemware are of blown glass, and 
these are again divided into those in which the stem 
is " drawn >? out from the piece composing the bowl, 
and those which are made from three separate gather 
ings of glass. 



Shaping Stemware 

For the drawn stems, the glassblower gives the 
bowl its general shape by blowing and rolling, or shap 
ing with the hand tools ; he then pulls or draws out a 
portion of the soft glass until it forms a slender stem. 
The upper picture in the frontispiece shows the stem 
being formed. 

On the end of the stem another bit of glass is then 
dropped, flattened out, and worked. 

If the glass is made of three gatherings the bowl is 
blown into a mold ; then another workman drops a bit 
of glass on the bowl and shapes a third piece for a 
foot, which is then flattened and shaped as in the drawn 

In all blown glass the bubble is closed over the top 
and must be cut away with shears or on a wheel. The 
glass is then reheated and the edges rounded off. The 
lower picture in the frontispiece shows the finished 
piece of stemware being carried to the lehrs. 

After shaping the foot the soft glass is attached to a 
glass knob or pontil called a " punty," while the 
" boss," that is, the shaped or rounded top of the bowl, 
is being removed. 

Variety of Shapes 

The shapes of the bowls vary widely. The principal 
ones are: 


1. Drawn, usually rather pointed. 

2. Straight-sided, either low and broad, or high 

and narrow. 

3. Ovoid, or rounded like an egg. 

4. Bell-shaped, with sides curving in and wide 


These are only the general types, of which there are 
many variations. 

The bowls of wine-glasses are usually plain. Gob 
lets, compotes, and other stemware may be engraved, 
etched, or gilded. 

Stem Variations 

Stems may be : 

1. Plain (straight or curved) 

2. Twisted 

3. Cut or " bossed " 

Plain stems are the most common. 

Twisted stems are made by impressing straight 
grooves in a rod of viscous glass and then catching 
the two ends and twisting them to give a spiral effect; 
or by fusing glass rods or canes together and twisting 
them. Color is sometimes added in the form of a 
twist " trailed " around the stem on the outside. 

Cut stems may be cut in rings, in straight, vertical 
lines, in spirals, or in fine patterns. 


The foot of a piece of stemware is not perfectly 
flat, but hollowed up somewhat in the middle. It may 
have a decoration on either the upper or the under side. 


Thin tumblers are blown into a mold and the top 
is cut off in the same manner as the tops of stemware. 
Heavier tumblers are usually made of pressed glass, 
though the finest cut tumblers are of blown lead glass 
cut on wheels. For pressed tumblers the glass is 
poured into the mold and pressed by the metal plunger. 
They are revolved in the mold while cooling in order 
that they may not show mold marks. The molds for 
this purpose are lined with charcoal or a similar prepa 
ration. Pressed tumblers may be decorated in any of 
the usual ways. 

If the mold has a pattern stamped in it to imitate 
cut glass, this revolving process is not possible. In 
this case, except for the cheapest grades, the mold 
marks are polished off. For semicut or floral-cut glass 
the patterns are sharpened and finished on the cutting 

Sets for Many Purposes 

Many articles of table glass are sold in sets. 
A water set consists of a carafe, bottle, or pitcher 
and six or twelve glasses of medium size. 


Iced tea or grape-juice sets consist of a pitcher and 
six tall glasses. They may also include an ice tub. 

Wine, cordial, or liqueur sets consist of a decanter 
and six glasses. Cordial or liqueur glasses are very 
small, holding from % to i% ozs. Wine glasses hold 
from 2 l /2 to 3 ozs. Cocktail and champagne glasses 
have a high stem and a shallow, wide bowl. 

Decanters are bottles with a low, broad bowl and a 
slender neck. Decanters for liqueurs are small and 
shaped like cruets for vinegar or oil. 

Water bottles or carafes are stouter than decanters, 
and are usually of heavier glass. 

Sherbet sets may consist of six or twelve glasses. 
The stems are more slender than those of wine glasses 
and the bowls shallower. 

Grapefruit sets consist of six or twelve large long- 
stemmed glasses, which may hold either the half-fruit 
surrounded with cracked ice, or a smaller glass which 
contains the fruit juice and is set in the ice. 

A punch or lemonade set consists of a large bowl, a 
ladle, and twelve glasses, often set on a plateau or a 
glass tray. 

Finger-bowls come in sets of six with or without 

Berry sets consist of a medium-sized bowl and six 
berry dishes. 

Coasters for use on a polished table are small, flat 


glass discs with rims for holding tumblers. They 
come in sets of four or six. 

A mayonnaise or a whipped cream set consists of a 
bowl, spoon, and saucer. 

An almond or a relish set consists of a small fancy 
dish and six very small side-dishes. 

Sugar and cream sets consist of a small pitcher and 
a bowl. 

A flower set consists of a large vase and four smaller 

Bedroom and toilet sets, also called guest or boudoir 
sets, consist of a water bottle covered with a small 
tumbler fitting closely down on it. 

Toilet bottles for medicines are of two standard 
sizes, 4 and 6 ozs., and with narrow or wide mouths, 
according to the material which they are intended to 
contain. The plain ones are of clear glass, usually 
square, with the name of the material they contain 
marked on them in black on a gold background. The 
more elaborate ones are decorated in enamels. Such 
bottles are often sold in sets of six or more, and may 
be fitted in a rack ready to be hung in the bathroom. 

Single Articles 

Many single articles are also sold in the Glassware 


Pitchers come in a great many styles, sizes, and de 

Tankards and jugs are both a form of pitcher, the 
first usually high and slender in shape and the latter 
low and broad. Tankards are of more varied and 
original designs than pitchers and jugs and are used 
for more special purposes. 

Cruets and bottles for holding dressing, vinegar, 
catsup, etc,, differ in shape and size according to their 
use. All of them have stoppers; cruets have handles 

Jars are wide mouthed and may be low or high. 
Sometimes they are squat, small, and square, though 
usually they are round. Sometimes they are fitted 
with a glass spoon and usually with stoppers or tops. 
Candy jars are tall, with curving sides and tops fin 
ished with elaborate handles or knobs. 

Glass bowls and dishes are of infinite variety in 
pressed, molded, or cut glass and with every type of- 
decoration. Salad bowls are low and broad while 
fruit bowls are high. Rose bowls are round with a 
small opening at the top. 

Ice and butter tubs are tub-shaped glass dishes with 

Compotes or sweetmeat dishes are stemware with 
flat bowls and high stems. 


Other bonbon dishes are set flat on the table,, and 
may be round, oval, or of any fancy shape, 

Casseroles, cake, pie, and bread pans, bean pots, 
ramekins, and other kind of baking dishes, are made of 
glass oven ware, which will stand a high temperature 
without cracking. (See manual on "Housefurnish- 
ings.") These articles, when fitted into any standard 
mounting, such as sterling or German silver, make 
attractive dishes from which to serve. Some of the 
higher-priced pieces are decorated with light-cut floral 
designs and sold for the same purpose as cut glass 
serving dishes. 

Glass trays have wooden or metal rims and may be 
transparent or backed with silk, cretonne, inlaid wood, 

Chapter IX 



The process of making mirrors has radically changed 
since 1835 when J. von Liebig invented the silver ni 
trate process. Before that time the glass was backed 
by amalgam, a mercury compound. 

Amalgam Mirrors 

The silvering of an amalgam mirror is quite an 
elaborate process. 

First a thin sheet of tin foil is spread out on a table 
and a small quantity of mercury rubbed over it. It is 
then carefully cleaned to remove dust. On this founda 
tion mercury is poured until it is about a quarter of 
an inch deep and the polished glass is slid over the 
mercury. Heavy weights are placed on the glass and 
the table is tilted so that all superfluous mercury will 
run off. After a period of twenty-four hours the 
weights are removed and the glass turned with the sil 
vered side up to dry and harden. 



Silvered Mirrors 

The real silvering of glass which has largely taken 
the place of the amalgam method is done with a solu 
tion of silver nitrate and ammonia. The silver nitrate 
is dissolved in an equal quantity of water, and ammonia 
is added to it. Then a very small quantity of potash 
and more ammonia and silver nitrate are added. 

This mixture may be applied in two ways by the 
hot or the cold process. In the former the glass is 
placed, polished side up, on a double metallic table 
heated by steam. The silver solution is combined with 
tartaric acid and poured over the heated glass. When 
dry it is protected by a coating of shellac, copal varnish, 
or red lead or is electroplated with copper. 

Telescope discs are silvered by the cold process. In 
this the silver nitrate solution is combined with a solu 
tion of sugar, water, and alcohol. The disc is placed 
on a rocking table and the mixture poured on, making 
a thick film. The water is allowed to remain for some 
time until the deposit has settled. The mirror is then 
cleaned with alcohol and burnished with chamois and 
jeweler's rouge. The silver forms the reflecting 

The amalgam mirrors are more permanent than 
silver, less affected by sun, heat, and dampness, but 
the mercury fumes are very bad for the workmen. 


Platinum Mirrors 

Platinum mirrors are made with a very thin film 
of chloride of platinum applied with a brush and fired 
in a kiln. They are grayish in color and are chiefly 
used in fancy boxes and similar articles because of 
their cheapness. 

Plateaux or Table Reflectors 

Plateaux are plate glass mirrors which are used as 
bases for centerpieces, punch-bowls, or other table fur 
nishings for decorative effect. They add greatly to 
the brilliancy of cut glass by increasing the reflection 
of light from its many facets. 

Plateaux are either round or oval and range from 8 
to 20 inches in diameter; the larger ones are used for 
punch sets or similar purposes. Some reflectors rest 
directly upon the table; others are raised on orna 
mental feet made of the same material as the rim. 

The outer edge of the glass is bevelled, the ridge 
being usually one-fourth or one-third of an inch wide; 
but in expensive pieces it may be an inch or more; 
sometimes the edge is cut, engraved, or etched. Serv 
ing plateaux have a rim of metal raised above the edge 
of the mirror in order to prevent glasses or cups from 
slipping off. 

The rims of these table reflectors are made of ster 
ling silver or white metal silver-plated. The under 


side of the reflectors is covered with thick paper, felt, 
or leather. An inner lining of thick cardboard serves 
to pad the glass and protect it. 

Ancient Mirrors 

Ancient mirrors were of metal bronze or silver 
though some glass mirrors were coated with tin. Glass 
mirrors were used in the Middle Ages and Venice made 
them on a commercial scale in the fifteenth century. 

Chapter X 


Fundamentals of Design 

In designing glassware two elements must be consid 
ered: shape and decoration. 

Importance of Shape 

On the flat surfaces of textile materials design can 
be expressed only in pattern, but each article made of 
glass has an individual shape which is the most im 
portant element in its design. 

Many people who make and handle 'glass do not 
seem to appreciate this fact They do not pay any 
attention to form, but proceed to heap decoration upon 
ugly and awkward pieces in order to make them beau 
tiful. No amount of decoration, however, can do 
this. It often only emphasizes the ugliness it seeks 
to conceal. 

The beautiful and tractable material which we call 
glass deserves artistic treatment and amply repays the 
artist who gives it his most careful workmanship. 


But the fact that it is so essentially beautiful has made 
stupid and vulgar designs marketable, whereas if 
they had been made of less shining material no one 
would have looked at them. 

Like all other materials, glass is most beautiful 
when treated according to its own nature and not made 
to imitate something else. Glass made by the Phoeni 
cians and the Romans was molded on a core of sand 
and the shapes of these old vessels are not unlike those 
made of pottery. They are often graceful but lack 
the delicacy which we associate with glass. The dis 
covery and perfection of the art of glass-blowing made 
possible a new and distinctive form of art. 

Shapes of Cut Glass and Blown Glass Articles 

Modern glassware may be divided into two general 
groups : heavy and substantial pieces whose decoration 
is cut deeply into the metal, and " blown glass " which 
is shaped by the expansion of air and finished by gentle 
manipulation while in the plastic state. 

While of course the best cut glass is made from 
blanks which are blown into a mold, when we speak of 
blown glass we mean the thin and apparently fragile 
types which show that they have had delicate handling. 

The difference in process determines not only the 
shape but the type of decoration suitable to it. 

Heavy cut glass is made in simple, well-proportioned 


shapes, and depends for its beauty upon the jeweled 
effect and the refraction of light produced by the deep 

The shapes of blown glass pieces may be simple 
also, differing but little from the lighter kinds of cut 
glass, but on the other hand they may be elaborate, 
and so delicately fashioned that stems or handles may 
be easily snapped with the fingers. Their decoration 
should be correspondingly dainty and fine. 

Purpose for which Article Is to be Used 

The shape of any article should be adapted to the 
purpose for which it is to be used. When glass is in 
tended for practical purposes as well as for ornament, 
those purposes should be given careful consideration. 

Pitchers are made to hold liquids. They should 
therefore be well balanced so that they cannot be easily 
overturned. The handle should be so constructed that 
the pitcher will tip at a convenient angle and the spout 
or lip so shaped that the contents of the pitcher will 
pour through it and not over its edges. 

Stemware for drinking glasses should have stems 
which may be comfortably and securely handled. The 
ridges on heavy glasses are partly for this purpose, 
but light wine glasses do not need such aids. The 
bowls of drinking glasses are also shaped according 
to their use. 


The shapes of large bowls and flat dishes should be 
determined in part by the kind of food or drink which 
they are to contain. 

Vases are of many shapes because flowers require 
different settings. Roses and violets, lilies and carna 
tions cannot be properly arranged in vases of the same 

Traditional shapes for glassware are usually good, 
but they may easily be vulgarized by the change of a 
curve, the shortening of a stem, or the addition of 
some meaningless detail. Only the practice of study 
ing pieces which are known to be beautiful will train 
the eye so that it will recognize beautiful lines and 

Designs for Cut Glass 

As the blanks for cut glass must be thick enough to 
stand the pressure and the grinding of the wheels, they 
naturally have a somewhat massive appearance. 

Old English cutters increased this massive effect by 
the simple shapes of their glassware and the straight 
lines of the miter or hobnail patterns. The pieces in 
Figure 8 are fine representatives of this type of cutting. 
Notice the curving lines sweeping upward over the 
shoulder of the vase and the dignity in each of the 

Courtesy of A. Gredelue 
Figure 8. Patterns in Miter Cutting 


The miter cuttings are either faceted like jewels or 
molded in simple blunt designs. 

The American floral cuttings are of several kinds. 
Some of them are as deep as miter cuttings and require 
a heavy blank, while others are shallow enough to re 
semble etching or engraving. The deep floral cuts 
are also combined with miter cuts or with light frosted 
floral designs. 

In order to conform to the general laws of design, 
great care must be taken to adapt the cutting to the 
shape and purpose of the piece of glass to be decorated. 
For example, the cutting on the lip of a jug or pitcher 
should be in lines radiating from its base to the edge. 
They should never cut across it. This applies also to 
cutting in the handle which should either be spiral 
(suggesting a continuous line) or follow the curve of 
the handle even more closely. 

Sprays of flowers or leafage springing from the 
straight line at the base of a bowl or pitcher are abrupt 
and awkward, while an upright conventional pattern is 

A branching spray may be graceful when it appears 
to start from, the stem of a goblet, especially if it fol 
lows the general line of the glass. 

In some designs the cuttings are so deep as to break 
completely the outline of the piece and make it appear 
ready to fall apart. 


Another defect is found in the use of patterns in 
straight bands which cross the article at any angle and 
even stop abruptly in the middle of a side. Straight 
lines are needed to steady a pattern, while curved lines 
give it grace and lightness. Such bands of ornament, 
however, are always noticeable and because they are 
stiff and aggressive they should follow the outline of 
the piece like a border. When they run all over the 
side they look like bands of embroidery trimming out 
of place. 

Individual cuttings should be proportioned to the 
size of the article. A single flower should not cover 
the whole side of a pitcher or vase and a star should 
not look like a rising sun. Small patterns usually give 
a more artistic effect, but they should not be so cut 
up with crossing lines as to look confused. 

Standard Cut Glass Patterns 

Among many admirable patterns in cut glass are : 

Colonial designs with simple geometrical divisions 
following the outline of the article. 

Small separate designs repeated on a plain or 
" mat " background. 

Light floral cuttings usually much conventional 
ized and sometimes frosted. 

Old English miter and hobnail patterns. 


Some combinations of miter and floral patterns are 
effective but they must be treated with care. They are 
successful only if the flowers are so conventional as to 
become a part of the miter pattern, or if the miter pat 
tern is so unobtrusive as to form a background or 
frame for the flowers. If the stiff lines of miter cut 
ting are alternated with sprays of flowers so that each 
form of cutting is thrown into relief, all unity of de 
sign is lost. 

Engraved Glass Patterns 

While deep cutting gives glass the brilliancy of 
jewels, the designs are restricted to formal and con 
ventional patterns. Light floral cutting is a. freer 
form, and engraving or etching may be given infinite 
variety because it is essentially a surface decoration. 

In criticizing the patterns in engraved glass we need 
not consider the hard material or the difficulties of 
workmanship ; we ask only for graceful outlines, clear 
ness, unity, and suitability. The greater freedom 
which is given to a designer of engraved glass does 
not, however, release him from the laws which govern 
all design or pattern-making. 

Laws of Design 

Some of these laws may be stated simply. First 
the elements of a pattern, that is, the figures, are 
either : 


Natural imitating nature as much as the mate 
rial will permit 

Conventional suggesting nature but simplified 
and adapted to the purpose of the decoration or 
the pattern. 

Abstract made up of repeated lines and pat 
terns which have no intentional resemblance to 
natural forms. (Sometimes it is hard to draw 
a clear line between very much conventionalized 
nature and abstract patterns.) 

Elements of Design 

Pattern designs are made up of lines, forms, and 

i. There must be a center of interest. In a stand 
ing piece of glassware this should usually be at a point 
a little above the middle of the article. In a bowl or 
flat piece it is either in the middle or at the handle end. 
The pattern may radiate from this point or it may only 
be given a little more emphasis there. 

In the case of simple borders or of repeated all-over 
patterns the shape of the article is made the center of 
interest to which the pattern calls attention. 

If the pattern starts from the base as in many gob 
lets, pitchers, and vases, the plain upper part is still 
a part of the design and is thrown out in relief like 


the broad petals of flowers springing out of the more 
complicated cup or calyx. 

2. The pattern should be well distributed and have 
a proper balance. This is especially important if the 
pattern is repeated a number of times, as a balance 
good enough for a single composition may not be good 
enough for repetition* 

3. The parts of a design must harmonize and be 
well bound together. The crossing of a design from 
one part of a piece having several sections to another 
is always effective. For example, the extension of 
the pattern from the stem to the bowl of stemware or 
from the handle to the body of a jug or pitcher gives 
a sense of unity and pleasure. 

Certain other principles of design contribute to the 
beauty of a pattern. Some of these are: 

Gradation, by which repeated forms vary in size. 

Symmetry and contrast, by which the design is 
given unity and variety. 

Radiation, which gives the eye a sense of com 
pleteness. In nature flowers, wings, and shells 
all have these beautiful radiating lines. 

Composition of line, which is the term given to 
the arrangement of lines so that they flow into 
one another; and even when the ends of the 
lines do not connect, the eye is guided by their 
general direction to the points of interest. 


Good Design 

In judging the different types of decoration, certain 
guiding principles should be recognized. 

The decoration should be suitable to the material and 
to the manner in which it is worked. 

Decoration should add interest to the article deco 
rated. It should be appropriate to the purpose of the 
article. The artist should always strike a balance 
between use and beauty. Very elaborate decoration is 
better suited to articles that are intended only for 
ornament than to those which are to be given hard 
daily use. 

Decoration should always bear a direct relation to 
the structural lines, that is, to the shape of the article. 
The pattern should either follow those lines or bring 
out their beauty by contrast. 

The Use of Color in Design 

The principles of design which apply to cut and 
engraved glass are no less important when the decora 
tion is in gold, silver, or colored enamel. Patterns 
which are given emphasis by any of these means 
should be even more carefully designed than those 
which are less noticeable. 

Nothing is in poorer taste than a cheap and tawdry 
design worked out in heavy gold or colored figures. 

Old Venetian glass is the best example of elaborate 


designs produced by the use of color. Its stripes and 
figure patterns, festoons, and lace-work show the mar 
velous possibilities of the plastic material. Some of 
these elaborate designs, however, are not beautiful but 
merely curious. Modern Venetian glass has fewer 
varieties and American copies of this glass are still 
simpler, having much less grace and delicacy of out 
line. This is due in part to the greater hardness of 
the metal of American glass and in part to the greater 
haste in production which leaves the workman no time 
for individual treatment of his material. 

When colored glass is transparent or translucent it 
has a unique beauty which requires the most sympa 
thetic treatment. 

Part III Decorative Glass 

Chapter XI 

Possibilities of Glass 

Glass is a material with almost unlimited possibili 
ties for the making of beautiful things. As we have 
seen, it may be blown, cut, or molded into the most 
exquisitely graceful shapes, while its transparency, 
crystal clearness, and bright surface make it second 
only to the diamond in its reflection of light and the 
prismatic colors which it scatters. 

In nearly all its forms glass is more or less orna 
mental, and attempts are usually made to give even the 
commonest articles, such as bottles, glass mugs, or 
pitchers, a graceful shape and some kind of decora 
tion. Most exquisite effects are produced with glass, 
moreover, in the hands of the true artist. Among the 
priceless treasures of ancient and modern times may 
be found many specimens of beautiful glass. 



Colored Decoration of Glass Surfaces 

The various methods of decorating the surface of 
glass are : 


Painting and enameling 



Gilding is an old form of glass decoration. It is 
done by the application of gold-leaf, liquid gold, or 
bronze powder. There are three methods of gilding : 

Gold resist 
Gold banding 
Application of gold-leaf 

Gold Resist 

The gold resist method is a combination of etching 
and gilding, as the design is first eaten out by the acid 
and then filled with gold. The piece is fired to unite 
the gold with the glass, and the design is burnished 
with a hard, smooth stone for a bright finish, or with 
spun glass or fine sand- for a dull finish. The gold 
may be what is called " liquid bright " gold, which is 
gold bullion melted down in an acid so that it may be 
applied with a brush. 


Gold Banding 

Gold banding is more simple than the gold resist 
method. It may be done with the same gold solutions, 
or a cheaper bronze powder may be used. The arti 
cle to be banded is placed on a revolving disc, and the 
workman applies the solution with a brush as it turns 
before him. Banding may also be done by machine. 
The gold is burnt in and burnished as with the resist 


Gold-leaf is gold beaten out extremely thin. It may 
be reduced to %50>ooo of an inch in thickness. It was 
formerly used for gilding but is now replaced by the 
two other methods. The gold leaf was attached to 
the glass by means of thin wax or glue and fired until 
it became fused upon the glass. 

Painting and Enameling 

Enameling is decorating glass with color by means 
of designs painted by hand in opaque glazes or enamels 
which unite with the glass when fired. The name is 
also given to a method of transferring printed patterns 
made of these materials to the glass by pasting them 
on and then firing the piece. 


Lacquering or Japanning 

This is done in the same way with cheaper materials 
mixed with shellac or varnish and baked on the sur 
face. It is an inexpensive and showy form of glass 

Silver Deposit Glass 

A very pleasing division of the Glassware Depart 
ment is the silver deposit glass, which is found in 
vases, water sets, wine sets, and other articles. The 
chief decoration is silver, which is overlaid upon it in 
graceful patterns. The foundation is of plain glass 
and sometimes has fine stone cutting covering the space 
which is not silvered. 

Process of Manufacture of Silver Deposit Ware 

The blanks for the silver deposit ware are designed 
to fit the decoration which is to be applied and are 
made to order in large quantities for the cut glass 

The process of manufacture from these blanks con 
sists of : 

Sketching the pattern 

Firing the design, to form the base for the silver 





Sketching the Pattern 

The designer outlines the decoration on the blank 
with either a brush or a stencil pattern. The material 
used for making the design is a metallic silver solution 
composed of silver 99.9 per cent pure, nitric acid, and 
other chemicals. It is a dark gray substance of the 
consistency of thick paint. The coating is allowed to 
dry before the next or firing process. 


The pieces are arranged on shelves in the kiln and 
the fire, usually of gas, is lighted. The temperature 
is gradully raised to 1200 C, a cherry red or white 
heat. This takes two hours or more; the whole 
process of raising and lowering the temperature re 
quires about four hours. During the process of firing 
the metal of the design melts and unites with the glass, 
which has also been softened by the heat. The design 
is white when it comes out of the furnace and is the 
surface for electroplating. 


After the pieces have cooled to a normal tem 
perature they are suspended on copper or brass rods in 
a tank filled with a solution of nitrate of silver. The 
rods are connected with the negative pole of a mag- 


netoelectric machine. On rods in the center of the 
tank are suspended bars of silver 99.9 per cent pure, 
connected with the positive pole of the machine. 

A current of electricity passed through the solution 
causes the tiny particles of silver in solution to arrange 
themselves on the metallic surface of the design. The 
rest of the glass is unaffected by the process as the 
silver will attach itself only to the metallic surface. 

The pieces are left in the solution from i% to 24 
hours, according to the desired thickness of the de 
posit. Sometimes a thin band is deposited and some 
times a heavy coat suitable for engraving or cutting. 
For ware of the best quality the silver deposited by the 
electroplating process is also 99.9 per cent pure. The 
design is still white when it is removed from the tank 
and remains so until it is polished. 

Sometimes a colored background is produced by 
covering the inside of the article with a colored enamel 
and firing the piece again. A backing of gold may be 
applied, which makes the design silver on one side and 
gold on the other. 


The polishing process is in two parts. 

First the workman holds the piece against a rapidly 
revolving, coarse, buffing wheel made of canton flannel 
softened by grease. This cuts down and smoothes the 


surface of the silver. The tiny particles which are 
rubbed off by the wheel are collected by suction and 
purified for later use. This process is called surface 

The second buffing is given with a softer buffing 
wheel covered with rouge. This gives the silver a 
high luster. 

Engraving the Silver Deposit 

There are two methods of brightening the design or 
adding to the delicacy of its detail. True engraving 
is done in the same way as other engraving on silver 
or gold, with delicate tools and most careful workman 
ship. The deposit must be reasonably thick and not 
too hard for the purpose. Engraving on silver de 
posit requires great care because of the brittle glass 

The other process is known as imitation engraving. 
In this the workman scratches away the metallic silver 
of the sketched design with needles of varying degrees 
of fineness. When the piece is electroplated the silver 
is not deposited along the lines thus scratched. The 
true engraving is distinguished from the imitation by 
the delicacy and accuracy of line. 

Original Process 

This artistic and popular form of decorated glass 


originated in France where the process was at first 
very elaborate and costly. The piece of glass was first 
coated with a suitable chemical to make the metal ad 
here to the glass and then electroplated with silver all 
over. The silver was then cut away from the design 
with hand tools. This early method, with some im 
provements, was followed until the present one was 

Meaning of the Term " Art Glass " 

All glass which has been given graceful form and 
artistic decoration might be included under the title 
u art glass/' but that which is cut, engraved, or orna 
mented with gold or silver is usually classed under 
those heads. 

The name art glass is generally applied to glass 
which is artistic not only in shape and design but is 
remarkable also for its beautiful color or mixture of 
colors. Sometimes the color is fused on the outside 
after the piece is formed ; but in the most characteris 
tic forms the Venetian, Bohemian, and Tiffany 
glass the color is introduced into the molten glass. 

Expert chemists are constantly at work discovering 
new combinations and methods of treatment which 
will produce new color effects. If two coloring oxides 
are used together, their union produces a new color 
which fnay not resemble either; by the multitude of 


these combinations the color scale of glass is rendered 
almost endless. 

Colored Glass 

Some of the popular forms of art glass are known 
under names denoting their color or their distinguish 
ing quality, as: 

Amber Mahogany 

Wisteria Black 

Mulberry Dark blue 

Green Rose 

Opaline or opal Cream-colored 

Moonlight iridescent White 

Verre de soie Metallic luster 

Pearl luster Gemmed or sealed 

Calcite Stained glass 

Amber glass is a clear brownish-yellow. It is found 
in tableware such as sherbet cups, thin wine glasses, 
and ornamental pieces, and also in vases of various 

Wisteria or mulberry glass is a rich but somber pur 
ple which has become popular recently. It is used 
almost entirely for decorative glass. 

Green glass is attractive even in an inexpensive 
quality and is much used for vases and fern dishes. 

Opaline or opal glass has a shimmering changeable 


effect, caused by the application of metallic oxides to 
the surface of the glass. It is known as moonlight 
iridescent, verre de soie, pearl luster, and calcite. 

Moonlight iridescent is a transparent, faintly opaline 
glass resembling the old Bohemian in its play of color. 

Verre de soie is a French glass almost transparent 
but slightly milky with a delicate pearly luster sug 
gestive of silk. It is called plain when of a pure white 
satiny finish or when only faintly opalescent. The 
colors are soft, pale lavender, green, and blue. It is 
often engraved with a light cutting. 

Pearl luster is similar to Verre de soie, but is heavier 
and of less delicate colors. It is also more opaque. 
The pieces are often decorated with gold banding or 
designs etched in gold. 

Calcite is a brilliantly opalescent, opaque glass sug 
gesting the more gorgeously colored Tiffany glass. 
The outside is creamy white and the inside has a beau 
tiful play of warm yellow, orange, green, and purple. 

Mahogany glass is one of the most recent popular 
forms of colored glass. It is made in flower bowls, 
fern dishes, vases, candlesticks, and other articles of 
decorative ware, either plain or ornamented with gold 
and silver. The glass is a deep brown or mahogany 
color with wavy lines to imitate wood graining. 

Black glass has had a vogue which is hard to under 
stand, as it is inappropriate for table decoration and is 


at all times a somber background or setting for flowers. 
The funereal effect is somewhat lightened by deco 
rations of bright colored flowers, but its popularity will 
not last after the novelty has worn off because it has 
few of the characteristics which give glass its beauty 
and charm, 

Dark blue, rose, and deep cream-colored glass may 
be seen in a large number of decorative pieces, some of 
which are very dainty and soft in tone. 

White glass is often ornamented with lines or bands 
of color and color is put on in the trailed decorations, 
handles, and finishing touches. In these cases the 
added colored glass is previously prepared in the form 
of short rods, which are reheated and applied as the 
design requires. 

Metallic lusters may be produced by placing par 
ticles of metal on the glass and fusing them into it. 
The fumes of stannous oxide will give glass an arti 
ficial iridescence by coating it with a thin layer of 
metallic tin. 

Gems or seals are made by dropping molten glass on 
the vessel while it is still soft and pressing it with 
metal seals. 

There is only one real stain for glass, which is called 
"silver stain" (see Chapter XVII). The term is 
applied to glass which is either colored in the batch 
with "pot metal" color or painted with enamel colors 
for windows. 


Flashed Glass 

Flashed glass is made by placing a very thin layer 
of deep ruby-colored glass upon the surface of a sheet 
of colorless glass of ordinary thickness. This is 
done by mixing the two kinds of glass in one gather 
ing which, when blown, produces this effect. Other 
colors are also used for the flashed glass process, 
though ruby red is the most common. Flashed glass 
may always be detected by looking closely at the edge 
of the sheet, when the thin layer of color is plainly 
evident It is in reality a veneer of color laid upon 
one side of a sheet of glass and may be removed in 
many cases by an acid or an abrasion. Flashed glass 
with several layers of different colors opens up a won 
derful field to the decorator and the cutter. 

Chapter XII 


Beauty of Design and Coloring in Venetian Glass 

In the section of the department devoted to art 
glass, pieces of Venetian glass immediately attract 
attention because of their daintiness, faint, delicate 
coloring, and artistic designs. Some seem to be 
scarcely more than thin brilliant bubbles of glass; 
others are more solid but with strange lines, twists, 
and flutings of color which have been introduced ap 
parently by magic. 

For the table there are decanters, glasses, cups, 
plates, finger-bowls, and many varieties of compotiers, 
bonbonnieres, and baskets for holding fruit or flowers. 
For the toilet table are scent bottles, powder boxes, and 
other dainty accessories ; while urns, candlesticks, and 
innumerable vases seem designed for beauty alone 
rather than for any sort of use. Among other fanci 
ful decorations may usually be found reproductions of 
natural-colored fruit in thin, transparent glass. 

Venetian glass has been celebrated for more than 



a thousand years for its graceful and delicate shapes 
and beautiful coloring. Though the industry has died 
down several times, it has been revived again and 
again. It flourishes today on the Island of Murano, 
from whence importations have been regularly ob 
tained by merchants who carry fine lines of glassware. 

Venetian glass is composed of: 


It lacks the brilliancy of lead glass, but its colors 
are exceedingly soft and beautiful and its luster is 
very deep and permanent. This luster is the result of 
many reheatings, some pieces being put into the fur 
nace as many as fifty times. It is highly fusible and 
therefore may be blown very thin and is readily 
molded into artistic shapes. It is also very light and 
fragile, though if reheated many times it becomes 
tougher than it appears to be. 

Curious Shapes 

The old Venetian workmen made many fantastic 
shapes, such as drinking glasses which resembled ships, 


whales, lions, or birds. Modern manufacture is less 
grotesque, but birds and fruits are common forms of 
decoration. The dragon is a favorite figure always, 
showing perhaps a strong Oriental influence. 

The materials in Venetian glass are seldom pure, 
and it is therefore apt to have a faint tinge of yellow; 
or if manganese has been added to neutralize the iron, 
it has a faint purplish hue. 

The Venetian glassmaker is an artist as well as a 
skilled artisan. As he stands before the working hole 
of his furnace, blowing his airy bubbles, tossing them 
up and down, and twisting and fashioning the delicate 
stems and handles, he gives each piece an individuality 
and charm which can be achieved only as the result of 
affectionate care and pleasure in his work. 

Process of Formation 

In making a vase, the body is first blown and then 
the piece is shaped to form the foot. It is reheated 
and the neck widened and shaped; the tube for the 
handle is formed and fastened to the body ; and it is 
again heated and given its final form. It may have 
a coil of glass around it from which the head of a 
dragon is deftly molded; or fruits and flowers of 
colored glass may be fused on, as the handle and foot 
have been. 


An interesting feature of Venetian glass is the in 
troduction of color in fine lines or spirals which seem 
to be embedded in some miraculous way in the 
material. The process is complicated, but not hard to 

Rods or " canes " of glass are made first by dipping 
the blowpipe into colored glass, drawing it out, mar- 
vering it into a cylinder 2 or 3 inches in length, and 
then dipping this glass cylinder into clear glass, which 
forms a coating all over it. This cane is 2 or 3 inches 
in diameter, and as broad as it is long, when the 
process of drawing is begun. 

One workman holds the end of the cane on his blow 
pipe, while another grasps the other end and walks 
slowly away, drawing it out until it is 420 yards in 
length and %5 inch in diameter, with a thin thread of 
color in the middle. In some cases the colored thread 
is wound around a rod to make a spiral before it is 
dipped in the clear glass, but the drawing out is the 
same. These canes are cut with shears in desired 
lengths and may be used in various ways. For a 
vase the canes may be placed side by side to line a 
mold, and a thin glass coating blown in the center to 
unite them. The piece is then reheated in the fur 
nace and worked, and finally is cut off with pincers 
which press the canes together at that point. 


Filigree Glass 

A filigree glass called reticelli is made by placing 
side by side a series of transparent rods or canes, each 
containing a twisted thread of colored or milk-white 
glass. The rods are then heated until they are fused 
into a single sheet of glass with a ribbed surface. 
Two sheets made in this. way are laid across each other, 
slanting so that a small air space is left between the 
rounding edges of the rods at each intersection. The 
sheets are then grasped with iron pincers and held in 
the furnace while they are twisted and formed into a 
vase. The effect of the bubbles of air inside the mass 
of glass, increasing and decreasing in size according 
to the shape of the piece, makes the manufacture seem 
almost incomprehensible. 

Cameo Glass 

Cameo glass is made by fusing a sheet of colored 
glass upon one of a different color, so that they can be 
cut in cameo effects. 

Mosaic Glass 

Mosaic glass is made of white threads on a blue 
ground, laid in mosaic patterns. 

Frosted Glass 

Frosted glass is made by rolling the soft piece in 
either white or colored powdered glass. 


Gold is sprinkled over the surface by a similar 

Laticella Glass 

Laticella glass is decorated with open network de 
signs. These designs are cut out of metal or paper 
and placed on the glass; they are held in place by 
essence of turpentine. A light powder is first sifted 
over the pattern and then it is removed. When the 
glass is heated the powder is melted and acts as a resist 
to the acid, into which the piece of glass is then dipped. 
The acid eats away the uncovered part of the glass, 
leaving a delicate lacelike pattern where the powder 
has been. 

Millefiori Glass 

Millefiori glass has small bunches or baskets of 
flowers in natural colors, portraits, or fanciful objects 
enclosed in cubes, domes, or balls of glass. This type 
of glass is used in paper weights or other small articles. 

Coloring of Venetian Glass 

This exquisite glassware has an almost unlimited 
range of colors, and these are equally beautiful, 
whether transparent or opaque. The best models are 
probably those that are made solely for ornament 
rather than as parts of table service, The lovely color- 


A Tazza B -Small Covered Vase C Biberon 

Figure 9. Examples of Venetian Glassware 


ing and original shapes look best when given a setting 
of their own and when they are not mingled with in 
congruous pieces of other types. 

American manufacturers, after many years of ex 
periment, have learned to make glassware which has 
most if not all of the characteristics of Venetian glass. 
One such manufacturer reproduces old patterns, even 
including the bubbles which are found in many old 
pieces. The old colorings such as turquoise, royal 
blue, and amethyst, are also found in these beautiful 

Figure 9 gives three examples of beautiful Venetian 
glass. Figure A shows a flat ornamental shallow cup 
known as a tazza. The shallow bowl is embossed to 
form a series of wavelets with angular points round 
the margin. The supporting stem is gracefully drawn 
with a conical foot formed of lace glass. 

Figure B shows a small covered vase beautifully 
decorated with fine white lace-work. The wings or 
handles Have been given the form of conventionalized 

Figure C is an example of a biberon or pitcher. It 
is distinguished by a scalloped mouth and the medal 
lions surmounting the handle and at the base of the 
spout. These medallions are ornamented by gilt satyr 
heads and are characteristic of the Venetian style. 


Bohemian Glass 

Modern Bohemian glass, which is made in Bohemia, 
Saxony, Bavaria, and Silesia, is usually colored or has 
color associated with it. It is generally heavier than 
Venetian glass, and in many cases the color is 
" flashed " or put on in thin layers, which are partly 
cut away, showing the clear crystal beneath. 

Bohemian glass is found in table glass, such as 
stemware, bottles, decanters, pitchers, flat dishes, and 
many forms of ornamental glass. 

The sand and potash from which Bohemian glass is 
made are very fine and pure and give it great bril 
liancy and lightness; because of the greater purity of 
its materials it is clearer than Venetian glass. The 
shapes of Bohemian glass vessels are less original, but 
often more serviceable, than the Murano pieces which 
they originally imitated. 

Methods of Ornamentation 

The best developed form of decoration is engraving, 
which is done on the white crystal or on flashed glass 
with equal effectiveness. A Bohemian named Casper 
Lehmann invented the method of engraving by holding 
the piece of glass against the points of whirling 

Designs are also etched with fluoric acid; but the 
etched glass, while cheaper, is not so satisfactory, be- 

Figure 10. Example of Bohemian Engraved Glass 


cause the designs cannot stand out so clearly and 

Besides the usual floral and geometrical designs, 
Bohemian glass is sometimes decorated with elaborate 
pictures, such as hunting scenes in medallions sur 
rounded by scrollwork. 

Cutting is done in conventional patterns, especially 
with flashed glass, which gives a very striking effect; 
cameo incrustation and enamel painting are also used. 

The usual colors of Bohemian glass are deep red, 
blue, green, and amber. Besides the " pot metal " 
colors which are mixed with the molten glass and the 
flashed colors put on as a casing, color is applied with 
a brush and fixed by firing the piece as with china. 

History of Bohemian Glass 

During the eighteenth century Bohemian glass be 
came more popular than the Venetian product and was 
exported to England, America, the East, and even to 
Italy. Some famous pieces are now to be found in 
museums and private collections. It was highly prized 
by the early Americans, and after a period in which it 
went out of fashion, it has again become popular be 
cause of its genuine merits, particularly its deep rich 
color, its original and finely executed designs, and its 
serviceable styles. 

Figure 10 shows a rare specimen of Bohemian en- 


graved glass of medieval workmanship. It is a shell- 
shaped cup with deep cuttings which form a series of 
bold, projecting compartments. The curved surfaces 
of these are beautifully engraved with figures, scrolls, 
and other ornaments. 

Chapter XIII 


Old Industry Revived 

In Tiffany favrile glass we have a modern produc 
tion which combines the beautiful rich colors in old 
cathedral windows with the surface iridescence of the 
ancient Egyptian and the Roman glass that has been 
buried in the earth for so many centuries. 

Window Glass 

After a number of years of experiment during which 
Mr. Tiffany had the glass made for him, he estab 
lished his own factory in 1892 at Corona, Long Island. 
Large panes of flat glass, some of them with delicate 
opaline colors and many different kinds of texture and 
degrees of density are produced. Some glass is clear, 
some crinkled or veiled, some clouded or speckled. 
The varieties of color combinations and textures are 
too numerous to mention. 

The colors for this rolled glass are all put into the 
batch while in its raw state. In other words, it is not 
enameled on the surface. The color is an integral part 
of the mass itself. 


There is other glass, however, which is still more 
beautiful and varied. The hot glass from different 
pots is thrown out on the table with a ladle; as many 
as seven different colors may be thrown together. 
The famous drapery effects are made by taking ad 
vantage of natural conditions while rolling and catch 
ing the ends of the hot sheet with iron hooks and crink 
ling it together. 

The color formulas are secret, but they are composed 
of different metallic oxides combined to form different 
tints and hues. Gold, copper, iron, and other metals 
are used lavishly, and the layers of glass are sometimes 
so heavily charged with these oxides that they are more 
like metal than glass. 

Peacock Glass 

Early in the production of favrile glass the wonder 
ful iridescence of the peacock feather inspired Mr. 
Tiffany with a desire to reproduce it in glass. Many 
attempts were made before success was achieved. 
The remarkable color variations were produced in each 
case by the application of different colored glasses, hav 
ing different chemical constituents in order that they 
might produce not only the diversified iridescence, but 
have also the characteristic body colors. 

All the colors of peacock glass are applied during the 
process of manufacture while the glasses are in a plas- 


tic or viscous condition, and the object is finished be 
fore it is placed in the annealing oven. Particular 
attention is drawn to this fact, for the reason that all 
imitations of Tiffany peacock vases have been made by 
the application of enamel colors after the piece is com 


The blown glass for table use and decorative glass 
is fashioned in graceful shapes which are less fanciful 
and odd than Venetian or Bohemian productions. 
They look more like Greek or Japanese designs. 

Flower motifs are used for smaller pieces with the 
fine veins and threads of color pulled and twisted by 
hooks during the forming process. 

The iridescence of antique glass is due to decom 
position of the surface brought about by chemical 
action during the long period of exposure to the air. 
The iridescence is not permanent and may be rubbed 
off. In favrile glass this iridescence is reproduced in 
the texture of the glass by a secret process and is per 

Characteristic Colors of Tiffany Favrile Glass 

Some of the characteristic and unusual color effects 
in Tiffany favrile glass are : 

Gold Lustre, an iridescent old-gold coloring. 


" Samian Red/' the red of a lobster's claw. 
"Mazarin Blue/' a deep, rich blue with a purple 

" Tel-al-amana " or Turquoise Blue, shading from 

turquoise to peacock green. 
"Aqua Marine/' the color of deep water with 

bronze lights in it, or pale green with objects 

apparently floating in water. 

In spite of its apparent delicacy, the glass is tough 
and durable. " Favfile " is a coined word derived 
from " fabric/' or " fabrile/' and means " made by 

Chapter XIV 



There are two kinds of vases, those which are in 
tended to hold flowers and those which are solely for 
ornament. The flower holders are usually made of 
glass and are shaped according to the kind and num 
ber of flowers to be contained. 

The low shapes are : 

Low round bowls, sometimes very shallow. 
Round bowls with an irregular edge. 
Bowls with a flaring, ruffled edge. 
Bowls with a collar or ruffle turned over. 
Rose bowls. 

The medium height shapes are: 


Flaring slightly. 

Flaring widely. 

Funnel-shaped, with a stem supported by a 




Curved gracefully in about one-third of the dis 
tance from the top and then out again in a 
flowing curve. 

Very slender, for single flowers. 

The tall shapes are : 

Straight-sided column. 

Flaring from a point near the base. 

Flaring at the top only. 

Very slender, for single long-stemmed flowers. 

Same as in those of medium height. 

Table Vases 

Sets of vases may consist of four, five, or six vases 
of similar shape for table decoration. The vase in 
tended for the center is of a larger size than the others. 
They are often connected by a glass chain. 

A table decoration which is a revival of an old 
French pattern consists of a silver or gilt standard 
holding vases shaped like horns of plenty and connected 
by ornamental festoons of the metal. 

A very graceful table vase consists of a low, broad 
bowl with a flower-like vase springing from the center. 

These flower holders may be found in cut, pressed, 
and art glass and in a number of colors white, 
green, amber, mulberry, blue, black, and opalescent. 
The clear, delicately tinted or white glass is in better 


taste than highly ornamented glass for this purpose, as 
the vase should be only a setting for the flowers and 
should not call attention to itself. 

Ornamental Vases 

Ornamental vases are of many graceful shapes, but 
are often quite unsuited for holding flowers. They 
may be elaborately decorated with gold and color, and 
are sometimes made of several different kinds of glass. 
Tiffany glass is often found in forms resembling 
flowers, either colored to make the resemblance more 
complete or covered with delicate tracery. 

Glass Candlesticks 

Candlesticks of glass are usually of simple forms. 
They are : 



Smaller at the top 

Curved out in the middle 

With the corners cut off 



Six-sided, usually straight 


The bases usually follow the lines of the stems, and 
are four- or six-sided, cut off at the corners, or round ; 
but sometimes they are simple in order to balance an 
elaborate stem, or ornamented to set off a plain stem. 
Bases of candlesticks should be large enough to sup 
port the stick and the candle above it. They are 
therefore rather broad and heavy. 

While candlesticks are sometimes found in colors, 
they are nearly always of white clear glass with plain 
or light frosted cutting. The bases are frequently cut 
underneath. The straight-sided Colonial candlestick 
has no ornamental cutting. Shapes which are less se 
vere may have floral or star designs, but they are sim 
ple in style. The patterns are often acid-engraved or 

Candelabra of glass are hung with pendants of 
prisms ending in diamond points, which catch the light 
and increase their brilliancy by reflection. 

Candlesticks for the dining table are usually of glass 
or silver as they then correspond with the table fur 

Miniature candlesticks are used for the dressing 
table and for children's dressers as well as for chil 
dren's parties. 

Chapter XV 


The Lamp Department 

A Lamp Department includes many varieties of 
lighting standards and fixtures. The illuminant may 
be oil, gas, or electricity, and the illuminating devices 
may be : 

Wall fixtures 
Ceiling fixtures 


Oil lamps are portable because they are independent 
of a central lighting plant. A good oil lamp is also 
less trying to the eyes than the more concentrated elec 
tric light, but on the other hand oil lamps are much 
more troublesome as they need frequent refilling and 
cleaning. Oil is seldom used in wall or ceiling fixtures 
except on shipboard or in the country, as storage bat- 



teries now supply electricity even for the lights of 
moving trains. 

Gas, which may be supplied by means of rigid pipes, 
is more widely used in wall or ceiling fixtures. The 
flexible tubes which are needed for table lamps are 
made of rubber, covered with woven textile tubing. 
The tubes are easily cracked when bent, are rather stiff 
and unwieldy, and not very durable. They must be 
carefully watched to prevent leakage of gas and are 
condemned by fire insurance companies. 

The use of electricity has added many new varieties 
of lighting fixtures as well as duplicating those used 
for candles, oil lamps, and gas. Portable lamps may 
be attached to a light flexible cord, which is often con 
cealed in the standard and can be connected with a 
floor or wall socket at will. 

Types of Oil Lamps 

Oil lamps are made with either one or two flat 
wicks, or, in the case of student lamps, with a tubular 
wick. The oil reservoir which feeds the lamp is 
usually below the wick but in the student type it is in 
a cylindrical well at the side. The original student 
lamp was so constructed that the oil was fed evenly 
and abundantly to the* tubular wick and burned with a 
clear, steady flame in a tall cylindrical chimney. It was 
supplied with a porcelain shade green on the upper side 


and white underneath which gave a soft, pleasant read 
ing light that has not been surpassed, and seldom 
equaled, by any other device. The lamp could be raised 
or lowered at will on the standard which consisted of 
a base and stiff rod to which the lamp was attached 
by a screw. These lamps were of German manufacture 
and are now almost impossible to secure. The "student" 
lamps now used have two flat wicks placed side by side 
with an elevated oil well. Double student lamps have 
a central well and lamps on each side. 

Oil lamps can be made into electric lamps by merely 
putting an incandescent bulb in place of the wick and 
attaching a cord at the side or running it up through 
the base. 

Adjustable Lamps 

Adjustable lamps are so constructed that they may 
be turned in various directions, as well as raised and 
lowered on the standard. Floor lamps have wood or 
metal bases and are conveniently placed behind a couch 
or chair with the light exactly where it is wanted. 

Table lamps of this type may be used to advantage 
at a dressing table or in a library. By turning the 
shade upside down they will give indirect lighting. 
Small adjustable lamps are made to fasten on the backs 
of chairs or bedposts for the benefit of invalids or 
for those who like to read in bed. "Gooseneck" 


lamps have a flexible standard which permits many 
different adjustments. 

Lamp Chimneys 

Lamp chimneys protect the flame of a lamp in the 
same way as the sides of the lantern or the bell around 
a candle. The usual shape for a lamp chimney is a 
shape between that of a cylinder and a cone cut off 
at the top. It is larger at the base than near the top, 
but not so large in proportion as the base of a cone. 
The Argand or student lamp chimney is a straight 
cylinder with a collar or projection near the bottom. 

Lamp chimneys must be well annealed or they will 
break when heated. They should never be damp when 
the lamp is lighted since a drop of water will cool the 
spot it touches and result in breakage. 

Lamp Stands 

Lamp stands or bases may be of wood, metal, 
pottery, or glass. Beautiful ones are made from bronze 
and porcelain vases by piercing the side or bottom of 
the vase to admit the cord, and adding a lamp socket 
and shade frame to the top. 

Floor lamps have standards of plain mahogany or 
of gilded and painted wood in French and oriental 
designs which are sometimes very elaborate. They are 
also of iron, bronze, and brass or of metal painted in 


enamels. Adjustable floor lamps have very plain 

The less expensive standards for either floor or table 
lamps are made of a composition metal which is poured 
into bronze molds and sprayed by means of the air 
brush or spraying machine with enamel and lacquer 

Old ivory is produced by spraying with white or 
cream-colored enamel and spreading a brown solution 
over it. In some places the solution is entirely removed 
and in others only partially wiped off. 

A green antique bronze effect is produced by wiping 
a greenish solution on a copper bronze base. 

Very hard water-proof enamels may be mistaken 
for the metals which they imitate if they are put on 
skilfully. They are sometimes almost as viscous as 
glass and can only be applied by the spraying process. 


Lampshades may be of metal, porcelain, glass, paper, 
or textiles in many forms. 

Metal shades for reading lamps may be solid with 
brass or copper above and a silvered surface beneath 
to reflect the light. The light is too concentrated to 
be pleasant in a room without other illumination. Metal 
shades are also made in pierced designs sometimes 
studded with glass jewels in oriental fashion. 


Porcelain lampshades give a soft, pleasant light and 
are made in almost unlimited varieties, though the green 
and white are most common. 

Glass shades are now usually made either in the 
heavy semi-translucent opal glass or in iridescent 
Tiffany glass. The light metal frames in which opal 
glass is set are usually of composition molded in the 
desired shape and sprayed with enamel. Curved pieces 
are heated and bent from flat sheets of glass by the 
shade manufacturer. Glass domes are of molded or 
pressed glass. Many of these are painted on the under 
side and fired in a kiln. 

Parchment shades are made of a specially prepared 
paper which is given a hard leathery finish. 

A textile shade having the appearance of painted 
glass is made of scrim or cheese-cloth, hung loosely 
on a metal frame and varnished until it shrinks to fit 
the foundation. It is painted with enamels and when 

finished has the translucence and brilliant surface of 


painted glass. 

Shirred silk, tapestry, and cretonne are all used in 
making lampshades. An interesting lamp for a library 
consists of a bronze standard supporting a bowl lined 
with mirrors which reflect the light of a high wattage 
lamp upon the ceiling. Beneath the bowl are three 
other bulbs to make a reading light, and suspended 
from the top of the bowl is a white lined silk shade 


which makes the combination look like a well-propor 
tioned lamp of ordinary construction. 

Candlesticks and Candelabra 

Candlesticks are also found in the Lamp Depart 
ment. Besides the glass candlesticks described in Chap 
ter XIV, those of porcelain or bisque, brass, bronze, 
iron, and wood are found. Porcelain candlesticks are 
usually simple in shape, being round, square, or col 
umnar with plain bases. They are decorated with gold 
bands, fluting, and little painted flowers. Some French 
candlesticks have Watteau figures at the side. 

Brass and bronze candlesticks are simple in design 
unless they are of oriental patterns when they are apt 
to have dragons coiled around them. Some beautiful 
Egyptian candlesticks are of pierced brass. Russian 
brass candlesticks and candelabra have a kind of fret 
work ornament. 

Iron candlesticks are sometimes very elaborate as 
wrought iron is soft and malleable and may be fash 
ioned into scrollwork or plant forms which are often 
graceful and ornamental. 

Candelabra are stands or holders for two or more 
candles. They are made of the same materials as 
single candlesticks, but brass is the most common 
material. Russian candelabra with five or seven 
branches have a somewhat oriental appearance due to 


their fretwork ornamentation. Hanging candelabra 
are also made of hammered brass. 

Candle protectors are shaped like an inverted bell 
with the opening at the top. They are found with 
brass candlesticks which have a deep broad saucer and 
ring for carrying, as in an antique bedroom candle. 
The deep bell covers the entire candle and protects it 
from gusts of wind. The modern candlestick, bell and 
all, is a reproduction of the plain Colonial design. 

Glass balls and prisms decorate many candlesticks 
and chandeliers (originally meaning "candle-holder"). 
Gilt candlesticks and candelabra with marble bases and 
a row of glass prisms hanging beneath the candle are 
very bright and sparkling. When the prisms are raised 
at the side to the level of the flame, the brilliancy is 
greatly increased. The designs for these are French. 

Chandeliers decorated with many rows of balls or 
prisms are made for use with either candles, gas, or 
electricity. The light reflected from so many sparkling 
facets makes the whole fixture shine like gorgeous 
chains of precious stones. When chandeliers of this 
type are used in dining-rooms and banquet halls, the 
latter are given an atmospheric chill because of the 
coldness of the light. The glass prisms and tears have 
the appearance of suspended icicles. Light of a red, 
glowing tone, exemplified by indirect candle light, adds 
to the cheerfulness and warmth. 



Lanterns may be either movable or fixed. They 
may take the form of either candles, lamps, gas burners, 
or incandescent lights protected on all sides by a box, 
or cover of glass and metal combined. Oriental lanterns 
have jewels of glass inserted in a metal fretwork more 
or less open. 

Lanterns are suspended above or beside doorways 
and in exposed arches or passages. In the country a 
lantern is the light for those who travel on foot or by 
wagon or carriage. For automobiles, lanterns are re 
placed by the oil or electric lamp with a lens (see 
Chapter XVI) to redirect the light from the polished 
reflector and lamp. 

Ships* lanterns have cylinder lenses to make the 
light source appear as a "pencil" of light, by which 
beam candlepowers are built up. Such lanterns are 
used exclusively for signals. 

Lighting Fixtures 

Wall and ceiling fixtures are of many kinds, includ 
ing the older types of candelabra and lanterns and also 
many new ones made possible by the use of electricity, 
which is fast taking the place of all other methods of 

Side fixtures for gas have : 


1. An open flame usually surrounded by a glass 

shade or globe open at the top. 

2, An incandescent mantle covering the outlet in 

order to increase the light per cubic foot of 
gas burned. These should bie protected from 
drafts by a small glass shell in addition to 
the outer globe or shade. 
Side fixtures for electricity are: 

1. Candelabra with porcelain candles and either 

pointed or round incandescent lamps to rep 
resent the flame. 

2. Bells or other pendent lights. 

3. Lights inserted in the wall and covered with 

translucent glass. 

4. Segments of bowls, molding, or other fixtures 

which conceal the light from below and reflect 
it upon the upper wall and ceiling. 
Ceiling fixtures for gas are all hanging and only 
differ in the shape of the fixture, the number of lights, 
and other details. 

Ceiling fixtures for electricity may be : 

1. Pendent with visible lights in bells, candles, lan 

terns, or other forms. 

2. Pendent with invisible lights: 

(a) In translucent bowls semi-indirect sys 


(b) In metal bowls indirect system. 


3 Combinations of the indirect and semi-indirect. 

4. Ceiling lights either visible or concealed with 

translucent glass. 

Electric light fixtures should always be characterized 
by grace and beauty, although many of them are not. 
The adaptability of electricity has made it possible to 
reproduce old types of lighting and to create new ones, 
and the many new methods of treating and decorating 
glass give a very wide range for originality. Yet we 
see hosts of ugly designs as well as beautiful ones. 

Indirect Lighting 

Indirect lighting is secured by throwing all the light 
rays upon a reflecting surface by which they are diffused 
over a large space. 

The concentrated light of high wattage lamps may 
be used to great advantage in this way. The ceiling 
so lighted gives a soft glow which is very pleasant 
to the eyes. 

The lights are concealed in metal bowls lined with 
mirrors which reflect the light either upon the ceiling 
or upon white porcelain discs which again reflect it 
but break up and refract, or turn, the rays so that they 
are scattered and softened. 

Semi-Indirect Lighting 

The great objection to indirect systems is that the 


light source appears as a black spot on a light ceiling. 
This is psychologically wrong. Furthermore the main 
tenance costs are unfavorable. 

Semi-indirect or shadowless lights aim to secure 
the same softness and diffusion with greater light 

Semi-indirect lights have white or ground glass 
globes or bowls instead of the metal ones. These 
"filter" the light rays while the ceiling or disc above 
reflects and disperses them. 

Daylight Glass 

Colored articles viewed by daylight may have an 
entirely different appearance when viewed by artificial 
light of a reddish character. Cloth or ribbon carefully 
matched for color by artificial light may not match at 
all when viewed by daylight. Thus there is a demand 
for artificial daylight for color matching. Very few 
realize what is demanded to produce artificially a light 
similar to that emitted from the sky. 

It has been known for a long time that in daylight 
there are certain proportions of all the different colors 
in the visible spectrum. Upon analysis of the light 
emitted from our most modern lamp it has been found 
that the greatest per cent lies in the red end of the 
spectrum, while very little of the blue is present. If 
we surround such a light with a glass which functions 


as a selecting medium, transmitting red, green, and blue 
light in the same proportions that appear in daylight 
and absorbing the rest, we will have a so-called "day 
light glass." This glass when viewed in daylight has 
a bluish appearance because it transmits all the blue, 
absorbing some of the green and a large percentage of 
the red. 

To produce a true artificial daylight in this way, 
efficiency must be sacrificed, since the light from the 
red end of the spectrum, forming about 80 per cent 
of the whole, is in part absorbed by the daylight glass 
and is therefore a total loss. Consequently this ideal 
reproduction of daylight is never sought. In daylight 
lamps, Mazda "Cz" 75 per cent of the light from the 
filament is transmitted by the glass. In daylight illumi 
nating glassware about 40 per cent of the light from 
the filament is absorbed, while in local color-matching 
units, the glass reproduces daylight more nearly, and 
therefore is still more inefficient than the two preced 
ing. When color-matching glass is used, 12 watts per 
candle produce the same illumination as i watt per 
candle without the glass, 

History of Lamps 

The use of lamps is very ancient, though the ancient 
lamp would be a poor substitute for the modern one. 

The type found in Grecian ruins and seen in old 


drawings was a sort of shallow pitcher with a spout 
or nozzle at one end for the wick and a ring or flattened 
projection at the other for a handle. In the middle 
was a hole through which the oil was poured. Some 
times there were several holes for wicks. These lamps 
were made of terra cotta or of bronze. They were 
often decorated and also made in fantastic shapes. Only 
vegetable or animal oils were used, none of which were 
so satisfactory as the modern petroleum. Wicks were 
of twisted or plaited strands of flax or cotton. 

Lamps were also suspended by chains. They were 
similar to the hand-lamps in shape and material, but 
the decoration was on the under side. Lamps burning 
incense were used in temples and at shrines. 

The words "candle" and "lamp" are used inter 
changeably in the Bible. There were no candles of the 
modern type and candlesticks were really lamp stands. 
The seven-branched golden candlestick of the Jewish 
tabernacle had seven lamps at the ends of its branches. 

The simplest form of portable light was the torch 
which consisted of a long pole, the end of which had 
been dipped in pitch or covered with some other in 
flammable and slow-burning material. 

Lanterns are also of very ancient origin. The earlier 
ones were covered with horn, bladder, or oiled paper, 
which was more or less translucent. Chinese and 
Japanese paper lanterns have been very popular in 


Europe and America because of their gay colors and 
sometimes fantastic shapes. The Japanese Feast of 
Lanterns is one of the most brilliant and beautiful of 
national festivals. 

The discovery in 1853 of a method by which petro 
leum or coal oil could be refined and used for lighting 
made almost as great a change as the invention of the 
incandescent light. Before that time, animal and vege 
table oils, especially sperm oil from the sperm whale, 
were used for lamps and lanterns. 

Illuminating gas began to be used in 1802 and the 
incandescent gas light in 1826. The incandescent elec 
tric lamp was invented by Edison in 1879. It consists 
of a bulb containing a thin platinum wire which be 
comes incandescent when an electric current passes 
through it. 

Chapter XVI 


Requirements of Optical Glass 

The behavior of glass toward light rays is not only 
the source of its beauty but makes it one of the most 
useful of all materials. The optical properties of glass 
magnify the range and power of human sight when used 
in the telescope or microscope, and correct defects in 
vision when used in eyeglasses or spectacles. We can 
hardly imagine the modern world without glass lenses. 

The requirements of optical glass are so much more 
rigid than those of ordinary types that it must be made 
of exceedingly refined materials fused in special fur 
naces, with scientific exactness at every stage of the 

The value of optical glass, especially for large lenses, 
depends upon its transparency, freedom from color, and 
homogeneity. Glass which we are accustomed to call 
"transparent" really absorbs a considerable amount of 
light, as we may see by looking through several sheets 
of window glass placed together. When this glass has 
a decided color, such as a greenish tint, it absorbs still 



more light. Now for tableware or window glass this 
tint may be overcome by using decolorizing materials, 
such as arsenic, cobalt, or manganese (see pages 9 and 
1 6), but these do not really take out the color; they 
only neutralize it and they limit still further the trans 
parency of the glass. Therefore they cannot be used 
when transparency is so important. The original 
materials must be as pure as it is possible to make them. 

Veins or Striae 

Homogeneity, or "sameness/ 5 is of the greatest im 
portance in optical glass. In order to understand this 
we must remember that glass is not a simple substance, 
or even a solid compound substance, but a mixture of 
several materials which have hardened while in a viscous 
state. During the processes of melting and fining, these 
materials are not distributed in exactly the same pro 
portions all through the glass, and the result is that 
even the clearest "plate," if looked at from the end 
(through its greatest thickness), will be seen to have 
veins or striae running through it where the mixing 
has been imperfect. Any alumina or other impurity 
which the hot metal has absorbed from the crucible, 
even though so small an amount that it could only be 
discovered by a chemical analysis, will also cause these 
streaks or veins. 

They are practically invisible in glass of ordinary 


thickness but they are a serious defect in optical glass, 
because they deflect the rays of light. The most per 
sistent experiments and laborious processes have been 
used to eliminate these veins. 

Furnaces and Crucibles 

The manufacture of optical glass is an exceedingly 
expensive operation. First the furnaces must be small, 
containing only one or two pots, since they need constant 
attention. The crucibles are made of specially prepared 
refractory clay and heated for several days in a kiln 
near "the furnace. 

When the pot has reached the proper temperature it 
is taken up on an iron fork and quickly transferred to 
the furnace. The opening is then bricked up, leaving 
only the hole through which the materials are to be 
introduced and the pot is heated still further. Finally, 
just before the glass materials are poured in, a small 
quantity of cullet of the same composition as the glass 
which is to be made, is thrown in and allowed to melt 
This makes a glass coating over the fire clay and pre 
vents impurities from becoming absorbed by the new 
glass batch. 


Materials for optical glass must be pure and finely 
pulverized in order that the melting and mixing shall be 


perfectly even. For special purposes many new 
materials are used such as : 

Hydrated oxide of alumina (instead of silica) 

Barium nitrate 

Zinc oxide 

Boric acid 


The proportions of the materials are also varied to 
such a degree that there is a long list of glasses to suit 
every optical need. There is, however, great danger 
in altering the chemical composition of glass because 
it can easily lose its power of resistance to attacks by 
acids or alkalies. Some of the finest optical glass will 
become blurred in a very short time if exposed to 
dampness or even to the atmosphere. 


The materials are put in the pot very slowly as they 
boil up at first and the air bubbles must all be expelled. 
When the pot is full it is closed except for a hole 
through which the "stirrer," usually of fire clay, is in 
troduced. This stirrer is kept in constant motion in 
order to make the mixture uniform until the process 
of fining is complete. It is then sometimes withdrawn, 
but is often allowed to remain bedded in the hardening 

The glass is cooled as rapidly as possible without 


chilling any one part more than another; after the cool 
ing has reached a certain point the pot is placed in an 
annealing kiln and the process continues more slowly. 
Otherwise the glass would fly to pieces. 

When cold the fire clay is broken off, sometimes 
leaving a solid mass but more often the glass has been 
cracked and falls into a number of pieces. These are 
not equally clear and some are rejected at once. The 
best pieces are pressed into iron molds and heated until 
they take the form of plates, discs, or blocks. When 
cooled polarized light is passed through this greatest 
diameter (where two faces have been ground flat and 
parallel) in order to detect striae. The entire batch may 
yield not more than 20 or 25 per cent of perfect glass 
and large pieces are much rarer than small ones. The 
cost of large lenses is therefore much greater in pro 
portion to their weight. 

Jena Glass 

Modern optical glass was revolutionized by the ex 
periments of E. Abbe and O. Schott, two German 
scientists who established a laboratory and works at 
Jena. In 1885 they received a grant from the govern 
ment, and with this aid were able to perfect their 
processes until Jena glass became the recognized 
standard for the world. 

One of the serious handicaps to the Allies in the 


Great War was their inability to obtain Jena glass for 
range-finders, periscopes, field glasses, and other optical 
instruments. Before the war closed England, France, 
and America were making optical glass declared to be 
as good as that of Jena. 

American Optical Glass 

In America the demand for the rapid production of 
field glasses and other instruments for the army and 
navy has led to a method of cooling which is less waste 
ful and expensive but produces a less perfect glass. 

The process of melting and fining is the same but 
the contents of the crucible is carefully poured out on 
a slab, as in rolled plate, instead of cooling in the pot. 
The bottom and sides of the pot are chilled in order to 
keep the temperature even and the sheet of glass formed 
in this way is less likely to splinter and crack than the 
thicker mass. No part of this glass is entirely free from 
strise but they are so slight that the glass will serve 
equally well for many purposes. Photograph lenses, 
spectacles, and field glasses are made from this glass. 

The annealing of optical glass is a very slow process. 
It is done in kilns and takes from five or six days to a 
number of weeks. 


The grinding of all lenses is a tedious process, but 


large telescope lenses are so extremely difficult to make 
that only a few men in the world have been entrusted 
with them. The greatest lens-making astronomer in 
the world was the late Dr. John A. Brashear who 
ground the lenses for the Yerkes and Mt. Wilson 
observatories. The Yerkes telescope at Williams Bay, 
Wisconsin, is the largest of its kind, the lens being 40 
inches in diameter. At Mt. Wilson there is a lens 72 
inches in diameter, and in Canada one 100 inches in 
diameter, weighing 2^ tons, but these are both mirror 
lenses in which minute defects would not be fatal. ( See 
Chapter IX.) 

For panoramic sight, the surface of a lens must be 
correct to 1/100,000 of an inch. French periscope 
lenses were practically perfect, as they must be to 
photograph the flight of a cannon ball. All photo 
graphic lenses must be exceedingly accurate. 

Lenses and Prisms 

Lenses and prisms are shaped so that they will 
change the course of the rays of light which pass 
through them. Lenses have curved surfaces which bend 
the .light rays, and prisms have plane or flat surfaces 
which are placed so that they turn the light rays and at 
their edges break up the white light into the colors 
which compose it. 

Lenses may: 


1. Magnify or produce an image larger than the 

object, as in a microscope. 

2. Reduce the size of the image, as in a photo 

graphic camera. 

3. Bend all the rays into a "pencil" of light, as in 

a lighthouse. 

4. Collect heat and light rays, as in a burning glass. 

Without lenses and prisms we should have no tele 
scopes or magnifying glasses, no spectroscopes, or even 
eyeglasses to correct defects in human sight. 

Spectacles or eyeglasses may be either flat, colored 
glass merely to protect the eyes from light or to con 
ceal deformities, or they may be an aid to defective 

For correcting defective vision, prisms and spheri 
cal and cylindrical lenses are used. Prisms correct 
double vision. Spherical lenses are: 

1. Convex, to correct "long sight" (hyperme- 


2. Concave, to correct "short sight" (myopia). 

Compound and cylindrical lenses are useful in correct 
ing various forms of defective eyesight. 

These lenses are commonly made of crown glass (see 
page 155) or rock crystal pebbles. 

Opera glasses and field glasses are small telescopes 
with two or more lenses so adjusted that they magnify 


objects at a distance and seem to bring them near to the 
eye. Crown glass or rolled optical glass is used for 
these lenses as the striae are invisible unless the lens 
is viewed edgewise. 

For compound lenses or other union glass it is neces 
sary to have glasses of exactly the same coefficient of 
expansion. To test this the glass is blown in con 
centric balls with one glass interior and the other 
exterior. If the outer one expands less than the inner 
it will crack and split off. The glasses are then reversed 
and the experiment repeated. 

Laboratory Glass 

In chemical or physical laboratories, glass is an in 
dispensable material. Jars, tubes, retorts, and crucibles 
are made of it because of its transparency, cleanliness, 
and relatively great resistance to the action of chemicals. 

It is corroded by strong alkalies, but the only acid 
which has a noticeable effect upon it is hydrofluoric. 
It is also a non-conductor of electricity which makes it 
an essential part of electrical equipment. 

For laboratory use, however, even the slight effects of 
chemicals on ordinary glass are serious drawbacks in 
making experiments and the danger of breakage either 
from shock or from sudden changes in temperature 
has caused scientists to try new combinations of 
materials in order to overcome these defects. 


Laboratory, as well as optical glass, was developed 
with the greatest success in Germany at the Jena factory 
which became the center of the world's supply. When 
the supply was cut off by the Great War other countries 
began to make experiments of their own. 

In the United States five or six new factories were 
soon started in order to fill this great need and much 
of their product has been passed by the Bureau of 
Standards by which all glass made for laboratory use 
must be tested. Seven tests are given in the following 
order to determine the resistance of the glass : 

1. Water 

2. Mineral acids 

3. Carbonate alkalies 

4. Caustic " 

5. Ammonia and salts of ammonia 

6. Heat shock 

7. Mechanical shock 

Resistance to chemicals and heat is even more im 
portant than to mechanical shock, such as dropping or 
striking, which may be more easily guarded against. 

Some of the materials used in these new glasses are 
rare and expensive and the process of manufacture 
requires much more care than ordinary glass. Their 
future development in this country may depend on some 
sort of government support, such as the Jena manu 
facturers have had. 



Thermometer tubes are made of blown glass drawn 
out very fine. One of the characteristics of viscous 
glass is that it will retain the shape given to a tube by 
the blowing process no matter how finely it may be 
drawn. If the opening is triangular in the beginning 
it will remain triangular and not become round. 

Clinical thermometers, for use in testing fever tem 
peratures, have a triangular tube, so small that the 
mercury cannot be seen except when the instrument is 
held in certain positions and will remain suspended until 
shaken down. 

The white line seen in the tubes of some ther 
mometers is made by flattening a cake of white enamel 
on the side of the bubble of glass and dipping them 
together into the molten glass again. When "drawn" 
the enamel follows the line of the tube. (See Chapter 

Chapter XVII 


Kinds of Glass Used in Windows 
The glass used in windows may be : 

Sheet glass 

Plate glass 

Rolled plate 

Figured rolled plate 

Polished rolled plate 

Sheet Glass is blown in cylinders 5 feet or more in 
length. These cylinders are split open and flattened 
out in a kiln. The glass is graded according to its 
freedom from wavy lines, air bubbles, and other 

Plate Glass is made by grinding and polishing the 
best quality of sheet glass on both sides in order to 
remove the wavy surface. 

Rolled plate is made by pouring the glass out upon 
a flat surface and rolling it. Rough cast plate is not 
transparent, but the surface may be polished like sheet 


Figured rolled plate is made by means of rollers with 
engraved surfaces which press a pattern into the glass 
before the metal has hardened. Rough and figured 
rolled plate is used for glass screens and for skylights 
where transparency is not desired. 

Polished rolled plate is much heavier than sheet glass, 
ranging in thickness from 3/16 of an inch upward. It 
is used for large panes, such as those in shop windows. 

Window Glazing 

Window glazing, the art of setting glass, has evolved 
the following forms of windows: 




English casement 

Leaded lights 

Double-Hung Windows 

The windows to which we are accustomed in modern 
houses are made in two sashes, with or without a central 
bar dividing the panes of glass. These sashes are hung 
in the window frame on pulleys with weights at the end 
of each cord to balance the sash, which may be raised 
and lowered with ease. In country houses may be 
found windows which have no weights and therefore 


requite spring bolts which slip into holes in the frame 
and hold them at certain heights. 

In double-hung windows the glass is set by the 
glazier in a groove near the outside of the framework 
of the sash and made secure with putty or cement 
pressed down around the edges on the outside. When 
the cement has hardened the window is also water 

Casement Windows 

In spite of the greater convenience of the double- 
hung windows, the older casement type is considered 
more artistic for many styles of architecture and has 
now come into quite general use. These casement win 
dows are swung on hinges like doors and are made of 
small panes of glass, sometimes set in a framework of 
wood, sometimes leaded, that is, put together with 
strips of lead either in simple squares or diamonds or 
in fancy patterns. 

French Windows 

French windows extend to the floor like double doors. 
They often open on porches, but sometimes only onto an 
iron grill on the outside of the base. French windows 
may have a single narrow pane of glass. They are 
characteristically high and narrow. 


English Casement Windows 

English casement windows are broad in proportion 
to their height with high sills and are usually grouped 
two or three in a row. When the framework of these 
windows is of wood it is made in the factory in the 
ordinary way, except that it has additional cross-pieces 
and smaller panes . 

Leaded Lights 

When window glass is set in lead the construction is 
not quite so simple. The lead for these windows is 
drawn by hydrostatic presses into long strips with a 
cross-section like the letter "H." (For metal drawing, 
see "Housefurnishings Manual.") There are over a 
hundred varieties of lead strips but all of them have 
a similar cross-section with two broad pieces or 
"flanges" connected by a narrow "heart." The width of 
the flanges ranges from 1/8 to i inch and the hearts 
also vary according to the thickness of the glass to be 
inserted. The hearts are sometimes made of steel to 
give greater stiffness, but the lead is then much harder 
to bend and manipulate. 

A window made of leaded lights is glazed on a flat 
table or bench. Two strips of lath are first placed so 
that they form a perfect right angle, and are securely 
fastened. This angle serves as the corner from which 
the window is built up. The leads are then straightened 


in a small vice and the flanges are opened with a wooden 
tool to admit the glass. If the latter is cut in squares 
or diamonds the glazing is done with long straight 
pieces of lead running perpendicularly or at the same 
angle with the line used as a base and short pieces of 
equal length for the intersecting sides. In elaborate 
patterns the leads may need a great deal of bending 
and manipulation, requiring the skill of a trained crafts 

When the glass has been placed in position it is 
secured with bench nails until the leads are applied, 
then another row is built in the same way. Finally the 
outer leads are laid on, two more laths are nailed 
against them, and the joints are all soldered on one 
side. It is then carefully turned over and soldered on 
the other side and a cement made of white lead, linseed 
oil, and putty is brushed into all the cracks and joints to 
make them water-proof. 

Kinds of Glass Used in Leaded Lights 

Colorless glass appears as : 

Crown glass, which is made by a spinning process 
and is in the shape of discs about 4 feet in 
diameter marked with concentric, wavy lines. 
The heavy centers of these discs are called "bull's 

Rippled glass, which has a wavy surface. 


Embossed, engraved, or etched glass (see Chapter 


Brilliant cut, on plain or frosted surfaces. 
Beveled and figured glass. 

Colored glass may be : 

Pot metal color, either solid or streaked by dipping 

the blow pipe into pots of different colors and 

working them together. 
Flashed glass (see page 106). 
Opalescent glass (see page 103). 
Antique glasses. 

Color may also be applied in the form of : 
Painted enamels and 
Silver stain. 

All of these colors are described in connection with 
the treatment of stained glass. 

Colored glass is used in mosaic patterns with the 
figures opalescent but studded with jewels of trans 
parent color. A medieval fashion has recently been 
revived, consisting of transparent leaded panes with 
small unsymmetrical, painted insets representing scenes, 
heraldic devices, or other symbols. 

Much of the domestic painted or opalescent glass is 
raw in color, ugly in design, and inappropriate to its 
setting. The poor quality of the glass and the crude 
designs have brought it into disfavor as the barest 

Courtesy of Pittsburgh Art Glass Co. 
Figure n. Leaded Glass 


simplicity is better than decoration badly done. There 
are, however, many opportunities for beautiful work, 
entirely suited to its setting. Uncolored leaded glass of 
simple pattern can hardly go wrong, but when color or 
pattern, or both, are added they must be handled with 
taste, some knowledge of color and design, and, if 
possible, an acquaintance with the history and develop 
ment of glass decoration. 

Figure n is a good example of domestic leaded 
lights, simple in treatment. 

History of Window Glass 

To our comfort-loving minds one of the most im 
portant uses of glass is in windows where its trans 
parency or translucency admits light into our homes 
while shutting out the air. In warm climates this is 
not so important, however, and we therefore find no 
evidences of the use of glass for this purpose in the 
Far East or in Egypt, though it was set as jewels or 
ornaments in their brass or stone work. 

There are remains of glass windows in the ruins of 
Herculaneum and Pompeii and those of Roman villas 
in Britain, but only the very rich could afford such a 
luxury. The openings in medieval castles were closed 
with wooden shutters and covered with draperies, but 
in the homes of burghers in the towns, glass was gradu 
ally introduced. In the ninth century glass was used 


in churches and domestic fashions seem to have fol 
lowed the ecclesiastical ones except that the treat 
ment was simpler, and more transparent glass was 

The finest domestic glass was made in Switzerland in 
the seventeenth century. This glass consisted chiefly 
of small panels exquisitely painted in miniature with 
enamel colors. Miniature painting on glass became 
the national art of Switzerland, where it held its own 
for a century after it had been lost or degraded in the 
rest of Europe. Picture panels which were made for 
wedding gifts or exchanged by trade guilds are now 
preserved in museums, especially the one at Lucerne. 
The favorite subjects were the exploits of the family or 
their coats of arms, which had become exceedingly 
elaborate in the seventeenth century. Some of our 
modern houses have revived this use of coats of arms 
in hall windows where the bright colors are at least 
pleasing to the eye, whether anybody knows what they 
mean or not. 

For many years the makers of window glass were 
interested only in perfecting their processes and de 
veloping a clear, flawless glass, but the time came when 
artists condemned this mechanically perfect glass as 
entirely lacking in beauty. Windows made with such 
material were only transparent squares in the wall to 
which they added no charm either of color or form. 


Stained Glass 

All glass colored in the batch might be called 
"stained, " but the term "stained glass" is usually under 
stood to refer to the glass found in church or memorial 
windows. The art of stained glass includes design as 
well as material. 

There are at the present time several conflicting 
theories concerning this form of art glass, which can 
be fully appreciated only by artists but are of interest 
to everyone interested in glass. The men and women 
who have the choosing of church windows should be 
able to distinguish between the different styles, even if 
they are not artists. 

The three types of modern stained glass windows are : 




Sometimes all three are to be found in one church, 
giving a unique effect, but not one to be commended. 
The enamel-painted window is the one most widely 
used, but it is believed by many artists to be a passing 
style. The two other types are the result of efforts to 
treat glass in a more characteristic way, but they pro 
ceed in almost opposite directions, differing not only in 
the treatment of the glass but also in the effects 


Enamel-Painted Windows 

Enamel-painted windows have been the generally ac 
cepted type since the seventeenth century and have no 
clear theory of glass design. They are made of colored 
glass pieces separated by lead lines, but, except in 
simple, geometrical patterns, the leads are not of great 

The more elaborate windows are heavily painted with 
enamels, that is, with metallic paints mixed with a 
flux to make them adhere to the glass. The effects 
sought are similar to those in other paintings and the 
artists have learned the painter's technique. Sometimes, 
in order to give the desired perspective, deep shadows 
and heavy masses of color are used, which make the 
glass practically opaque. 

Eminent artists have painted these pictures and the 
designs are often beautiful, but they are not true "glass 
pictures." They suffer from the use of a method which 
belongs to pictures intended to be looked at rather than 
through and they do not bring out the beaut} of the 

Opalescent Windows 

Opalescent, or Tiffany, windows are the result of 
many experiments made by the artist, John La Farge, 
and further developed by Louis C. Tiffany, who tried 
to create a new art of glass, stained in the batch instead 
of being superficially painted (see page 119)- 


The material is very beautiful, with an exquisite 
blending of colors, delicate shading, and iridescence pro 
duced by the combinations of rich, metallic oxides and 
remarkable effects of line and form made by the skilful 
manipulation of the glass in its molten state. (See 
Chapter XIII, "Tiffany Favrile Glass.") 

Antique Glass Windows 

Antique windows are the result of a study of the 
early art of stained glass. They are made of trans 
parent colored gja^s and are therefore nearer the 
enameled windows than the opalescent, but the only 
pigment used on them is peroxide of iron without a 
flux. This is sometimes replaced by peroxide of 
manganese. If the former is used it gives a brown 
shading while the manganese is black but no new color 
is added by either one. They only serve to give detail 
to the picture outlined by the leads and to lower the 
light. According to an old proverb, "The glass work 
er's palette is his glass." 

Antique Glass 

The making of stained glass like that of the thirteenth 
and fourteenth centuries has been considered one of the 
lost arts, because glass of such richness and variety of 
color and depth of tone was supposed to have been made 
by processes of which the secret had been lost. 


This is not the fact. The beauty of the old glass was 
not due to secret formulas. On the contrary its variety 
of color and texture was largely the result of imper 
fections in the glass ! The modern, commercially per 
fect glass with which we are familiar is too uniform 
for the glassworker's purpose. 

The old, crude methods of manufacture were most 
uncertain as to product. The various metallic oxides 
produce different results at different furnace tempera 
tures and sudden variations in temperature will have 
strange effects. 

Air bubbles and impurities were the result of crude 
methods of fining and variations in thickness were due 
to other limitations. We do not know whether the old 
glassworkers appreciated the value of these imperfec 
tions which were sometimes serious enough to mar the 
beauty of the metal, but often had the opposite effect. 
Air bubbles or 8 dust when seen against the light became 
prismatic, refracting the rays of light like the inner 
facets of jewels and giving to the glass a crystalline 
quality which it ordinarily lacks. 

Streaks of color, clouded effects, and uneven thick 
ness were variations which added much to the possibili 
ties of the color scale and the craftsman of that day 
added to these unsought variations the mixing of colors 
on the blowpipe, flashing the metal from one pot on that 
of another, and other devices for producing the effect 


he wanted. His greatest allies, however, were the 
lead lines which gave to each of his strong, pure colors 
its greatest intensity and to the whole picture its 
wonderful brilliancy. 

Reproductions of Antique Glass 

When artists began again to use the strong lead lines 
and to aim at true glass technique, they also tried to 
reproduce the metal of the old craftsman. In this effort 
they have been more than successful. It is now pos 
sible to get air bubbles and streaks and cloudiness by 
scientific methods instead of depending on accident. 

The best antique glass is of English manufacture. 
It is all made by hand and each successful variety has 
back of it many costly experiments. For this reason the 
maker must have the promise of support in his venture 
and thus far the United States has not given this 
promise. Windows in this country are a combination 
of the flat-toned domestic and imported antique glass, 
the latter being used for the more brilliant effects. 

Antique glass is usually blown in cylinders and then 
flattened into sheets 24 inches long and 16 inches wide. 
One variety called "Venetian" is blown into a mold hav 
ing a screw pattern on the inner surface. While still 
soft it is removed to another mold having the screw 
pattern running in the opposite direction so that the 


intersecting lines produce lozenges which are used as 

Color is flashed on a colorless base, as in ruby glass, 
which is always made in this way, or it may be^on 
another color, gold pink (made with gold oxide) being 
flashed on yellow, blue, or purple to make certain very 
brilliant colors. 

A glass similar to the antique, called "Norman slab/' 
is colorless, or, rather, a greenish white. It is blown 
into a mold shaped like an iron box, which chills the 
metal so quickly that it spreads over the mold very un 
evenly, producing a wavy appearance like water. 

The Making of Stained Glass Windows 

Like architecture, with which it has a very close con 
nection, stained glass is both an art and a craft. It 
begins with the design of the artist, but it ends with the 
very practical art of glazing. Windows are openings 
through which a building is lighted and therefore 
should be wind-proof and rain-proof, but not light- 
proof, as some unfortunately are. ' 

The process of constructing a window involves many 

minor operatons. These may be grouped as follows : 

i. Making the small colored design. For picture 

windows there are two additional stages in this first 

process : 


(a) Making figure studies 

(b) Drawing large cartoons 

2. Making the large "cut line" drawings indicating 
the position of the leads. The sections of these draw 
ings are all numbered. 

3. Cutting out the sections with pattern shears, which 
are three-bladed, leaving a space for the leads. 

4. Laying each section on glass of the color desired 
and cutting the glass with a steel wheel (instead of a 
diamond as it was formerly done). For enamel-painted 
windows only the ground color is needed. In antique 
windows the pieces are smaller and there is great care 
taken to choose those of exactly the right texture and 
color gradations. For opalescent windows the choice in 
volves not only color but lines and suggestions of form, 
as the picture is to be a glass mosaic. If the right effect 
is not secured by the first choice the glass may be 
"plated/ * with one piece on top of another. 

5. The pieces are next assembled on a glass easel for 
the purpose of completing the design. They are tem 
porarily attached to this easel with wax. 

6. Enamel-painted windows are now ready for the 
completion of the design. As the different colored 
enamels are not of the same composition they do not 
"fire" at the same temperature and the heat necessary 
to fuse one color on the glass would melt another one 
completely. They must therefore have the harder 


enamels put on and fired first and the softer ones later. 

Antique windows are painted in a similar way except 
that the pigment is without variation of color or flux. 
The method, however, is quite different because the 
effect is to be flat. The design is worked over several 
times, always with iron peroxide, called "antique 

First, the outlines are drawn in with the pigment 
mixed with French fat oil and turpentine. The whole 
design is then stippled over with a soft badger brush, 
the pigment being mixed with water and gum arable. 
This is rubbed down to give shading and high lights, 
the glass is given a coating of coal oil and the design 
again strengthened and softened by the application of 
the pigment ground in oil of tar and coal oil. Both 
hard and soft brushes are used, some of them very finely 
pointed and with handles having sharp metallic points 
with which the color may be cut away. 

Some of the best work is a combination of etching 
and painting. Flashed glass is used which has the 
upper layer cut away in certain places, exposing the 
color beneath and this coat may be further varied with 
a coat of silver stain. 

Silver Stain 

This is the one true stain used on all kinds of stained 
glass. It is made of a solution of silver which gives 


the glass a beautiful series of yellows from a pale, 
greenish shade to a deep orange, without destroying its 

Opalescent glass also must have certain features 
painted, such as the faces, hands, and feet of persons 
in the pictures, but it cannot be fired without losing its 
play of color and iridescence. 


Glass was formerly put in a muffle or closed kiln for 
firing, in order that it might be protected from the 
fumes and smoke of the fuel. Small gas furnaces are 
now used. The best kilns are tunnel-shaped, about 8 
feet long and 3 feet wide, with an arched roof 21/2 feet 
high in the center. The glass rests on an asbestos- 
covered tray on each side of which is a series of gas 
jets which may be turned on and off either separately 
or at the main key. 

Firing in a gas kiln takes from half an hour to an 
hour and a half. If the results are not satisfactory the 
process is repeated. 


Glazing is the final assembling of the window. Two 
straight pieces of wood are placed at right angles on 
the glazier's bench and securely fastened, forming the 
corner from which the window is to be put together. 


The leads are stretched and straightened and clipped 
into suitable lengths and the outside leads are laid 
against these laths. 

The working drawing is placed on the board and, 
row after row, the glass is set in place with leads be 
tween. At intervals pieces of wire are soldered in 
which are afterwards twisted around tie bars. 

The antique window designs need the leads which are 
of several different widths, some of them quite broad. 
The glass in these windows is in small pieces, and if 
the leads were not part of the design they would mar it. 

In the painted windows the leads are not an important 
part of the design, and in the opalescent they are still 
more inconspicuous. 

When the assembling is completed the joints are 
coated with oleic acid and soldered on both sides. 
Finally a cement made of white lead, linseed oil, and 
putty is brushed into the spaces between the leads and 
the glass and worked down into the cracks until the 
window is water-proof. 

Stained glass windows assume one of two following 
forms : 

Lancet, high, narrow, and pointed at the top like a 

Rose or circular. 

The windows may be divided into sections by stone 


Effect of the Finished Window 

The beauty of a stained glass window is very much 
affected by its location. Those which are to be placed 
nearly on a level with the eye can be given delicate 
treatment, but those to be seen at a distance must be 
given bold lines or the design will be weak and blurred. 
The lines are not only softened by distance but the light 
which shines through the glass is refracted so that it 
narrows even the leads. Work which may seem harsh 
and crude on the easel is only strong and well defined 
at the proper distance. 

The effect of light is all-important. Windows with 
"hot" colors should not be. on the south side of -the 
building to receive the glare of a summer sun, but 
against a cool, gray light. The brilliancy of adjoining 
windows and the lights which will fall across the 
picture, must also be considered. 

The artist who is to design the window should al 
ways see its setting. Otherwise he cannot know all o 
these points. Drawings and photographs may indicate 
the architecture of the building, but cannot give an 
idea of color and light. 

Stained Glass Design 

Enamel-painted and opalescent windows are alike in 
one respect. They are intended to look like pictures. 
Rounded forms, shadows, and perspective give one the 


sense of looking through the window at a scene beyond. 
The pictures are often beautiful, but they are not archi 
tectural in design, as wall decorations should be, and 
they sadly obscure the light. 

In this respect the opalescent glass is an even greater 
offender than that which is painted in enamels. The 
large quantities of metallic oxides and the creases and 
ridges which look so like drapery or landscapes are too 
heavy to be translucent. These mosaics are seen at their 
best only when there is a cross-light or when the build 
ing is otherwise illuminated than by the windows. 

Antique windows are not paintings in, the ordinary 
sense, that is, they do not attempt the painter's effects 
of perspective. The strong leaded lines enclosing their 
fragments of color give to the artist a material which 
is quite unique. Not form or even color is the basis of 
this art, but light. 

The designs in antique windows are not massive even 
when the space to be filled is a large one. One of the 
unfortunate features of the massive designs sometimes 
seen is that they dwarf their surroundings. By keep 
ing the designs small, the apparent height of the window 
is increased. Grisaille (or grayish) windows have a 
background of silvery gray with suggestions of green, 
blue, or amber, and medallions of more intense colors 
set against it. 

The glass worker's pigment is used to intensify the 


I |-wSuiu <w-rft>hi|i 

Figure 12. A Stained Glass Window 

The Captain Simpkins memorial window, Church of St. John, the Evangelist, 
Beverly, Mass., designed and made by Charles J. Connick 


effects of light and color even more than to outline the 
pattern. It is heaviest near the leads, lowering the tone 
of the light and preventing its refraction across them. 
From the leads it shades off gradually to a point of 
greatest clearness and brilliancy near the center of the 

On the other hand the design itself is almost in 
silhouette ; the shadows are indicated by differences in 
color tone rather than with pigment. 

In Gothic architecture the leads are often but a con 
tinuation of the stone traceries in which the windows 
are set and the painted outlines have the effect of a 
finer series of leads, while each piece of glass is treated 
in such a way as to bring out all its color values. 

Since windows are usually seen at a considerable 
distance the color makes its impression before any de 
sign can be seen. If the distance is great the design 
may not be clearly seen at all, the window is only a 
group of color spots or color masses. 

In one modern Gothic church the most beautiful 
window is behind the organ where only a suggestion of 
its design can be seen. But no person can enter the 
church without having his attention arrested by the 
shafts of intense blue light, like blue fire behind the 
silver gray organ pipes. 

Figure 12 is an example of a lancet window with the 


background in grisaille and the central figure and the 
side panels in rich but clear colors. The lead lines form 
a part of the pattern. In the small panes are symbolic 

Part IV The Glass Industry 

Chapter XVIII 


Wonders of Glass-Making 

" Among the discoveries due to chance and perfected 
by man's intellect, the invention of glass is certainly one 
of the most important. Two examples taken from 
two extremes of creation, the infinitely great and the 
imperceptibly small, will sufficiently prove this the 
telescope, which brings the heavenly bodies within the 
range of the astronomer's study, and the microscope, 
which may be said to be still more useful." 1 

Glassmakers of Egypt 

The ancient Egyptians were workers in glass as they 
were in pottery and many other arts. 

The first evidence of the domestic use of glass is 
found in the frescoes of Thebes, and on some of the 
earliest tombs glassblowers are 'represented. Many 
remnants of Egyptian glass, all beautifully iridescent 
with earth-made colors, have been found also in ruins 

l Wonders of Glass-making. Sauzay. 



of buried palaces which have been excavated. 
The Egyptians made many articles of a deep, trans 
parent blue glass, using it for small vases, mosaics, 
beads, imitation stones, scarabs, bracelets, scent bottles, 
and charms. Less often they colored their ornaments 
with pale buff, deep green, and in rare cases with red. 
Sometimes the piece was decorated with bands of 
white, yellow, or turquoise blue, and in some instances 
the whole surface was colored. Birds in mosaics are 
said to have been represented with such accuracy and 
delicacy of detail that each separate feather of wing 
and tail could be easily distinguished. In the British 
Museum is a human-headed hawk not exceeding, three- 
fourths of an inch in its greatest dimension. Other 
examples characteristic of Egyptian skill in the art of 
glass-making are specimens of beautiful glass jewelry 
found in Memphis and now at the Salle Historique at 
the Louvre, and a yellow glass scent bottle with the 
name in blue glass. In the British Museum is an ex 
quisite little blue and orange glass bottle bearing the 
name of Thothmes II (eighteenth dynasty, about 1590 
B.C.); and in the Bulak Museum is an elaborate 
bracelet found in the tomb of the mother of one of the 
kings of the eighteenth dynasty. It is formed of 
microscopic gold, red, and blue glass beads, strung on 
fine gold wire in a symmetrical design of triangles. 


Theban Works of Art 

Some of the cups of varied colors found in Thebes 
show great skill in what may be called glass-porcelain, 
usually in blue or green. Both the molding and the 
cutting of glass were also practiced there, as shown in 
figures and ornaments cast in a mold, and in vases and 
beads engraved in various designs. 

Glass of Other Oriental Countries 

Glass was also made in India and in China, but the 
Indian glass was very defective and Indian methods 
were primitive. The Chinese probably copied the 
methods of the Phoenicians, but most of their glass 
was in imitation of precious stones. 

Assyrian Workmanship 

Quantities of small glass articles, such as amulets, 
were early exported from Egypt to Assyria. The As 
syrians understood the glazing of pottery and did 
much of it, as we learn from their ornaments and their 
glazed architectural bricks. The first specimen of 
their glass was a vase found in Nineveh, inscribed with 
the name of an early king; while a greenish glass bowl 
found in 1852 bears the name of Sargon (722 B.C.) 
that is, in the eighth century B.C. This vase is now in 
the British Museum. It is supposed to be the oldest 


specimen of transparent glass yet discovered; as those 
from Egypt appear to belong to a period earlier than 
the sixth or seventh century B. c. The Sargon vase 
was blown in one solid piece and then hollowed out and 
shaped by a turning machine. Two larger vessels of 
alabaster were found with it and all were probably 
used for holding ointment or perfume. A rock crystal 
lens was also found, supposed to have been ground on 
a lapidary's wheel and to have been used as a mag 
nifying glass. Blue glazed pottery, glass bottles, and 
other vases of elegant shape, some of them decorated 
in gilt, were unearthed at the same time. 

Persian Glassware 

Persia also produced some beautiful glass, specimens 
of which may be found in the British Museum and 
other collections; but Tyre and Sidon were the cities 
most celebrated for glass-making. 

According to an old legend, sailors from a Tyrian 
ship carrying a cargo of niter, went on shore to 
eat. Finding no stones upon which to place their pot, 
they set it upon blocks of niter, and used seaweed for 
fuel When the fire died down they discovered that 
the niter had melted and, fusing with the sand and the 
ashes of the seaweed, had made glass. Whether this 
story is fact or fable, it is certain that the glass fac- 


tories of this enterprising group of merchants were 
noted up to and during Roman times. 

Sidon is said to have invented glass mirrors and to 
have known the value of manganese in making glass 

We know that Phoenician citizens used the blowpipe 
and the graver. 

Characteristics of Grecian Glass 

Greece, which excelled in pottery, paid little atten 
tion to glass-making. The Greeks in Rhodes produced 
glass vessels, such as small bowls of clear crystal and 
harmonious colors. Bottles of opaque blue or green 
decorated with gold have been found in Grecian tombs. 
As a rule the Greeks preferred the blue or crystal glass. 
Grecian articles of glass must, however, have been 
largely imported, since there is no trace of the manu 
facture of glass on Greek soil. 

Roman Glass 

The Romans used glass extensively for domestic 
and architectural purposes and also for personal adorn 
ment. Factories were established as early as the first 
century A.D. The emperor Nero was a great lover 
of glass and an enthusiastic collector, and by his ex 
ample stimulated the rich Romans to pay extrava- 


gant prices for glass, crystal, and murrine ( a costly ma 
terial not definitely known) vases to use on the table 
at their banquets. Through the encouragement of the 
royal families there was also much luxurious ex 
travagance in toilet and perfume bottles; the Roman 
ladies and their slaves carried their own toilet ap 
paratus to the baths. Mourners gathered their tears 
in tear-bottles hardly one-half inch in height, and 
placed them beside the ashes of their friends ; and also 
poured wine and milk from fancy bottles on the funeral 
pyres. Some of these funeral and tear-bottles may be 
found in the Louvre. Other bottles supposed to have 
been intended for presents are engraved with the pic 
ture of a heart and the word " Amor." Beautiful 
color effects were obtained from the use of green, 
blue, purple, amethyst, amber, brown, and rose, in both 
opaque and transparent glass ; some eight or ten shades 
of blue varying from lapis to turquoise were known. 

Varieties of Glassware 

There were also many styles of design for the glass 
ware, including perfume, cosmetic, and funeral bot 
tles, drinking cups, flasks, bowls and other vessels, dice, 
mosaics, small ornaments, and especially imitation 
stones; the latter were often carved as intaglios and 
cameos, or set in beautiful filigree work. Cinerary 

A Amphora B and C Ampullas D Vase 
Figure 13. Examples of Roman Molded Glass 


urns were used. Roman ladies carried glass balls to 
cool and whiten their hands, changing the ball as the 
glass heated. At banquets slaves poured wine and 
water from large carafes or decanters into the drink 
ing cups of the guests. 

Glass was blown, molded, pressed, and cut. The 
crystal glass made by the Romans was clearer and 
stronger than that of the Egyptians, and so like the 
real or rock crystal as almost to defy detection. 

In Figure 13, A shows a violet-colored Roman am 
phora a tall two-handled jar which was used to 
hold wine or oil The surface has decayed and has the 
iridescence found in most ancient glass. It is encircled 
with a series of horizontal alternate narrow flutings 
and ribbons. 

Figure B portrays an ampulla, a vase used to hold 
perfumes and oil. It is made of opaque light blue 
glass much decayed, molded in relief, and ornamented 
with an amphora, a diota (two-handled cup) and other 
vases placed between six columns supporting pointed 
arches. Near the base are bunches of grapes and fes 

Figure C gives an illustration of another ampulla. 
It is of light green glass with the surface divided by 
projecting lines into 6 compartments containing in re 
lief an amphora, a syrinx (Pan's pipes), a patera (a 


shallow bowl or cup used for pouring libations), and 
crossed scepters; above these compartments, the ves 
sel is fluted. 

Figure D represents a vase of dark glass much de 
cayed, upon which a human face is molded in relief. 

Glass of Pompeii and Herculaneum 

Both these cities have yielded varied and splendid 
examples of Roman glass now stored in the Bourbon 
Museum of Naples and elsewhere. More than four 
thousand such articles have been collected, among 
them the Naples and Portland vases discovered in a 
tomb in 1644 and placed in the British Museum. The 
Portland vase is always referred to as the most beau 
tiful known specimen of the glass engraver's skill. It 
was at first supposed to be carved from a precious 
stone, but on closer inspection it was found to be made 
of a dark blue glass with exquisite cameo-like figures 
which are carved out of a superimposed layer of 
opaque white. 

Varieties of Bottles 

Among the Pompeiian relics are numbers of square 
glass bottles in which housekeepers kept their wine, 
oil, vinegar, honey, etc.; some of these bottles are a 
foot and a half high, while there are hundreds of 
smaller bottles of other types. There are glass plates 


fourteen inches across. A fragment of one patera 
made of a blue glass that is as splendid as a sapphire, 
with milk-white cameos on it, representing a twig of 
ivy leaves enclosing the head of a ram, suggests Pliny's 
words, " They sculptured glass more delicately than 

Other Glassware 

Glass cups, called Christian glass, in colored designs, 
are also found among the relics of the catacombs of 
Rome. The subjects pictured are religious, such as the 
Nativity and the raising of Lazarus. Some of the cups 
have purple in the draperies, green in the sea waves, 
and pink in the faces, while the more ornate specimens 
are decorated with silver, gold-leaf, and powdered 
gold. Little crystal glass fish are also found, together 
with vases supposed to have held sacred oils. 

Venetian Glass 

Very little is known of glass manufacture in Italy 
immediately after the fall of the Roman Empire, as the 
industry almost died out with the removal of the 
government from Rome to Constantinople. Some 
Italian refugees, during the invasion of the terrible 
Huns under their leader Attila, fled to Venice, where 
the industry was kept alive. Among these refugees 
were glassmakers, who about the fifth century started 


the industry, which was soon to become one of the 
most extensive and world renowned in the history of 
glass-making. The marine alkali-yielding plants and 
the abundance of sand about Venice had, no doubt, 
much to do with the rapid development and the beau 
tiful products of the Venetian glassmakers. But the 
Venetians also utilized foreign commodities. Boats 
were sent to Syria to collect the white sand for which 
their glassware was celebrated, and special woods were 
brought from great distances. 

The Emperor Constantine had taken expert glass- 
makers to Constantinople, but the fall of that city in 
1204 drove many Greek workmen back to Venice with 
their new recipes to enrich the industry. The Vene 
tians guarded their secrets with the greatest care. If 
any workman carried his skill to another city he was 
ordered back and his relatives were imprisoned until 
he came. Glassmakers were highly honored and many 
of them were given the rank of nobles. 

Figure 14 shows an ancient Venetian glass furnace 
with the glassblowers at work, and Figure 15 shows 
the tools used. 

Murano a Famous Glass Center 

In 1291 fear of fire drove the council to pass laws 
abolishing glass furnaces within the city, and the glass- 
makers were driven to the lagoon island of Murano, a 

ABlowpipes B Glass Pots C Working Holes 
Figure 14. Ancient Venetian Glass Furnace 



suburb of Venice, which has been a famous glass center 
ever since. In the early part of the seventeenth cen 
tury there were three hundred glass manufactories in 
Murano, and nowhere in the world could their beau 
tiful products be matched. The vases, cups, bottles, 
and decanters of delicate crystal were prized by kings 
and often were more costly than if they had been made 
of gold. 

In 1300, Murano artists began to coat plates of glass 
with an amalgam of tin and mercury, and their mir 
rors became the standard throughout Europe. In 1436 
they began to use color in glass; the earlier products 
were clear crystal with a greenish or violet tinge. 

Murano made the most beautiful beads, tableware, 
bric-a-brac, and the beautiful brown glass flecked with 
brass filings known as aventurin. Their glass was soft 
so that it could be spun, woven, or fashioned into the 
daintiest designs, and they also understood that the 
reheating of glass added brilliancy; a single piece, it is 
said, was heated as many as fifty times. To the 
Murano artists, with their extreme delicacy of taste 
and touch inherited from their ancestors, coupled with 
endless study of their art, may be ascribed a fame 
which eclipsed that of any other glass-making center 
in Italy, so that for a long time Venetian glass enjoyed 
a monopoly. In recent years there has been a revival 
of the skill of the Venetian craftsmen. 


Development of Art in Other Countries 

The development of glass-making in France, Ger 
many, and England in the seventeenth and eighteenth 
centuries had an injurious effect on the industry in 
Murano. The invention of flint glass was a serious 
blow to the industry, as flint glass is soft and heavy and 
suitable for cutting, while the light, thin Venetian ware 
cannot be cut. Glassmaking in Murano declined dur 
ing the eighteenth century to such an extent that of 
300 factories only one remained in the early part of 
the nineteenth century. 

The modern renaissance of Venetian glass is due to 
the efforts of C. Pietro Biguglia (1845) and later of 
Salviati, who revived the old processes and invented 
others, and practiced them with freedom and fine ar 
tistic instinct. Backed by English capitalists, Biguglia 
reproduced old forms of Venetian glass and exhibited 
it at industrial expositions with conspicuous success. 

Spanish Glass 

Numerous traces of early glass furnaces are found 
in Spain, a result no doubt of the spread of the in 
dustry from Rome throughout her provinces. Small 
jars, cups, phials, thickly molded saltcellars, tear-bot 
tles, and bracelets found in tombs suggest home manu 
facture of them in the valleys of the Pyrenees. Much 
of the glass of Barcelona (1324) bears a resemblance 


to the old Venetian glass and seems to have been made 
both for home and export use. Many beautiful ex 
amples of Spanish glass are found in the South Ken 
sington Museum. 

Bohemian Glass 

During the sixteenth century glass-making in Bo 
hemia became a recognized industry, when goblets and 
tankards of white glass with colored coats of arms, 
millefiori (see Chapter XII), and other decorated glass 
were made in its factories. In 1609 Casper Lehmann 
invented engraving on glass and the ancient art of 
cutting was revived. In 1679 ru by glass was intro 
duced, and the action of hydrofluoric acid on glass, 
which made etching possible, was also discovered or 
applied in 1670. 

The industry developed rapidly during the seven 
teenth and eighteenth centuries. Bohemian glass was 
not so delicately fashioned as the Venetian, but it was 
of purer materials and therefore clearer; the engraved 
glass of Bohemia was very beautiful. Flashed glass 
(see Chapter XI) was much used, and was most effec 
tive when engraved or cut to bring out the contrast 
of color between the rich ruby or violet and the crystal 

Other Varieties 

A potash-lime glass was made by the Germans in 


imitation of the Venetian, but the colorless variety has 
always been known as Bohemian glass. 

Toward the end of the sixteenth century skilled rock 
crystal cutters from Milan advanced the art rapidly 
in the crystal and glass cutting factories at Prague, 

Early Art in France 

France had some glass factories as early as the 
second century ; the imperial factory at Frontencennes 
was supposedly the cradle of all later factories in Nor 
mandy. The glass was of low quality and of a 
greenish tinge. During the Roman occupation the 
native industry died out and Roman glass was used 
instead. The characteristic Roman articles vases, 
wine bottles, dishes, etc. are found, some of them 
bearing such Latin inscriptions as " Vale " and 
" Salve/' French museums abound in specimens of 
this Roman glass which has been unearthed in their 

By 667 A. D., foreign workmen, particularly Greeks 
and Romans, began to revive the industry. 

The city of Poitiers abounded in wood and other 
materials, and ruins of ovens and melting pots mark 
sites in its districts where glass was made, 

Normandy was the first province to grant privileges 
to glass workers. In the tenth and eleventh centuries 


noble families followed the art, and " gentlemen " 
from Normandy went to establish factories in other 
cities. In the time of St. Louis it was fashionable to 
use glass on the table. 

While the Eastern countries excelled in mosaics, to 
the French belongs the distinction of superior work in 
glass painting and stained windows. Painted glass 
windows are said to have originated in the School of 
Limoges about 800 A. D., at which time a Venetian 
colony was established there. The casting of plate 
glass was discovered about 1693; blowing was em 
ployed up to this time, 

The town of Baccarat in France has since 1765 been 
the center of plate glass and crystal factories which 
are world renowned. It is one of the three oldest 
glass centers in western Europe. The people of the 
district all work in the factories as their ancestors have 
done for generations, and produce a glass of great 
beauty and delicacy. In 1823 D'Artiques established 
in this town the world renowned " Crystalleries de 

Many European palaces and public buildings are 
decorated with panel or plate mirrors, crystal glass 
cases, lamps, and vases of Baccarat glass. The fac 
tories excel in cut and engraved pieces, light and deep 
rock crystal, and glass with rich ornamentation in gold. 
One odd and interesting feature is the glass which is 


decorated with paintings on opaque foundations to re 
semble porcelain. 

English Glass 

The records of ancient glass-making in England are 
meager. The Druids had rudely shaped colored beads 
which they used as charms and which they probably 
obtained in trading with the Phoenicians, who went to 
Britain for tin. Most of the glass found in tombs and 
recovered cities is Roman, however, as it resembles 
that of Rome, France, and middle Europe. Among 
such relics are beads, vases, and balls of crystal glass, 
tear-vases and bottles six or eight inches square. 
Glass must have been plentiful even in Saxon times, 
judging from the quantity found. The oldest painted 
windows in England are those of Canterbury (1174), 
which date from the Norman period. 

Glass tumblers and ale and beer glasses were in use 
on the tables at banquets. In a drawing on an Anglo- 
Saxon calendar in the British Museum, seated figures 
are shown drinking from glass cups or elongated tum 
blers of hornlike shape and blown very thin. 

Importation rather than home manufacture seems to 
have been encouraged. 

Growth of the Glass Industry in England 

In 1677 the Duke of Buckingham brought glass- 


makers from Murano to Lambeth, England, to make 
crystal vases, looking-glasses, and other articles. In 
1685 political disturbances sent French glassmakers to 
England, so that in 1696 there were 88 glass factories 
making chiefly bottles, mirrors, and ordinary flint glass 

The distinction of perfecting lead or flint glass be 
longs to England, as does also the development of the 
art of glass cutting. Lead glass was much softer and 
more sparkling than the lime crystal used by the Ger 
mans and the Bohemians, and the English cut glass 
soon surpassed any that was made on the continent. 
London, Bristol, Birmingham, Belfast, Dublin, and 
Glasgow became important glass-cutting centers. 

The finest specimens of English glassware belong to 
the period between 1780 and 1810. Nearly all of it 
was tableware. Stemware of all kinds, tumblers, de 
canters, saltcellars, pitchers, and mugs in almost end 
less variety are now gathered by the collectors of this 
fine type of glassware. Some glasses were thin and 
delicate, while others were, heavy enough to pound the 
table without injury when this was the custom. 

Characteristics of English Glass 

English glass shows marked individuality. Bristol 
glass is especially prized ; but all of it is interesting and 
most of it is beautiful. From the many " baluster " 


stems and plain bowls of the earlier types, to the fine 
cutting, engraving, and trailed decoration of later 
manufacture, one may trace a clear line of develop 
ment. Certain peculiarities, such as " tears " or bub 
bles of air which are found in earlier sterns, are devel 
oped by a process of drawing out and twisting into the 
mysterious air twists of later specimens. 

This old glass has the clear ring of the lead crystal 
and much of it is beautifully colored. Greens, from a 
clear apple-green to the deep color of the emerald, deep 
sapphire blue, amethyst, and old rose may be found 
among these old glasses. Political history is also writ 
ten in the Jacobite pictures and symbols with which 
some of them are engraved. 

.English tableware lacks the delicacy of the Vene 
tian and the fanciful decoration of the Bohemian glass, 
but it is wonderfully satisfactory for its purpose. 

Chapter XIX 



Early Experiments 

The American colonists made a number of attempts 
to produce glass, but for various reasons they were un 
successful. A few English glassmakers came to 
Jamestown in 1608 and tried to start a factory, and 
early records mention some Italian bead-makers. 
Wheeling had several small glass houses in its early 
history, and Pennsylvania launched several enterprises 
but all were shortlived. There was a lack of skilled 
workmen and the sand used was of inferior quality. 

There was no general development of the industry 
until about the middle of the nineteenth century. The 
glass that was produced before that time was poor in 
quality and crude in style. The better grades were im 
ported from England, and only such articles as com 
mon bottles and heavy table glass were of American 

About 1840 attempts were made to produce some 



decorative ware. Bottles were made in sapphire blue, 
emerald green, claret, and other brilliant colors ; some 
were shaped like log cabins or cider barrels, and the 
American eagle or the stars and stripes were used as 
patriotic decorations for tableware. Opal glass was 
fashionable for candlesticks, drawer handles, and simi 
lar articles. 

Pioneer Glass-Making Concerns 

The foundation of the glass industry was laid near 
Boston when the New England Glass Works was es 
tablished, and for many years Boston led in the manu 
facture of flint and colored glass of all kinds. 

Th6 first furnace had six pots and forty workmen, 
but in 1865 five furnaces, of ten pots each, were 
operated, five hundred workmen were employed, and 
glass valued at $500,000 was produced annually. 

Through the enterprise and liberal policy of this 
company, factories for making glass were also estab 
lished in other parts of the country. Workmen were 
brought from abroad, and capital was freely expended 
to make the industry permanent. 

In 1855 William L. Libby, who was 'then a confi 
dential clerk of one of the large glass importers located 
in Boston, bought the glass factory of his employers 
and for twenty years enjoyed an enviable reputation in 
the Massachusetts industry. Realizing the necessity of 


cheap fuel, however, he moved to Toledo, where first 
natural gas and later petroleum were available. The 
Libby Glass Company of Toledo, one of the largest of 
the United States glass manufacturing concerns, is the 

Another notably successful plant was started in 1852 
by Christopher Dorflinger of Brooklyn, with a capital 
of $1,000, for making glass for lamps and chimneys. 
The discovery of petroleum at that time had created a 
great demand for lamps, and his furnaces increased 
from one with five small pots to four in 1861 and fif 
teen in 1865. During that year he moved his fac 
tories to White Mills, Pennsylvania, where he now 
operates one of the largest manufactories of cut glass. 

Growth of the Industry 

The growth of the glass industry in the United 
States has been due to : 

The development of pressed glass. 

The invention of the automatic bottle machine. 

The improvements in furnaces. 

The use of oil and gas for fuel. 

Pressed Glassware 

The manufacture of glass by means of metal molds 
was practiced to some extent in England and America 
as early as 1834. The idea of pressing the molten 


glass into the required shape by means of a rnetal core 
or plunger was suggested by a carpenter in Sandwich, 
Massachusetts, and taken up by the New England Glass 
Company with successful results. 

The perfection of this type of glassware was 
achieved by a Pittsburgh company which took the first 
prize for fine pressed glass at the Paris Exposition in 
1867. The goblets and wine glasses produced by this 
company could hardly be distinguished from those 
made by blowing and cutting. 

Pressed Lime Glass 

Until 1864 pressed glass was always made of flint or 
lead, with potash and saltpeter, which made it nearly 
as expensive as cut glass. In that year a Wheeling 
glass company experimented with bicarbonate of soda 
and lime, and succeeded in making a clear, brilliant 
glass at about one-third the cost of the lead glass. 

The use of this lime glass caused a rapid growth in 
the pressed glass industry in the West, and a corre 
sponding loss to the flint glass manufacturers of the 
East, who could not compete with the western product 
on account of its lower cost of production. This re 
sulted in the disappearance of many eastern glass 
Invasion of Foreign Markets 

The purity of color and the excellent design of 


American pressed glass, together with its comparative 
cheapness, has made a market for it not only at home 
but also in foreign countries, both in Europe and 
South America. 

The Owens Bottle Machine 

Another discovery which revolutionized the bottle- 
making industry was the invention and perfection of 
the Owens automatic bottle machine. No hand opera 
tions are necessary except the oiling and care of 
the machine. It makes bottles of all sizes and shapes, 
and the saving of labor is enormous. In 1914 between 
sixty and seventy of these machines were in use. 

Improvements in Furnaces 

There were no important changes made in the types 
of glass furnaces used until 1870, when increased 
competition led to improvements by which less fuel 
was made to produce more heat. Larger furnaces 
were built, many of them holding from thirteen to fif 
teen pots, which sometimes contained two tons of glass 

The use of natural gas for fuel gave the Middle 
West its greatest advantages over other sections of the 
country ; and it is there that the glass industry now has 
its center. There are, however, several important 
manufacturing centers in the East, among them Mill- 


ville and Glassboro, New Jersey ; and Bridgeton, White 
Mills, and Philadelphia, Pennsylvania. 

In the Middle West 

In western Pennsylvania, Carbondale is a center, 
West Virginia and Ohio have many plants, and Toledo, 
Ohio, makes large quantities of pressed glass as well as 
superior blanks for eastern cut glass factories. 

Muncie and Gas City, Indiana, are important cen-. 

Alton, Illinois, has the largest flint bottle manufac 
tories in the world, 4,500 workmen being employed. 
Chicago and some small towns in the neighborhood 
have numerous plants for manufacturing and cutting. 

Pittsburgh, Pennsylvania, is the greatest glass 
manufacturing center in the country. It produces al 
most every type of glass. In 1887 the Pittsburgh Plate 
Glass Company began the creation of what is now the 
greatest plate glass works in the world. 

Pennsylvania leads as the glass-producing state, 
with West Virginia second. The large deposits of 
white siliceous sand in the latter state, as well as the 
abundant supply of coal and natural gas, have caused 
the rapid growth of the industry. 

Today the United States leads the world in the 
manufacture of glass and glassware. It imports some 
European art glass and glass for lenses, but exports 


greater quantities of machine-made glassware and a 
large amount of cut glass. 

As a result of war conditions, the trade in glass be 
tween this country and South America has been 
greatly increased, as well as the orders from European 
markets. American machinery has been installed in 
many foreign glass manufacturing plants. 

America imports glass from Austria Hungary, Ger 
many, France, England, Belgium, Italy, The Nether 
lands, Sweden, and Japan. In Belgium glass-making 
was considered the national industry before the war. 

Chapter XX 


Qualifications for Selling Glass 

The selling of glassware requires taste, intelligence, 
and imagination on the part of the salesperson. While 
its beauty always attracts shoppers, the great variety 
of styles and designs is confusing. Also most people 
fail to appreciate the quality and suitability of glass 
ware with the same discrimination which they show in 
choosing clothing and other practical articles. 

A knowledge of the composition of glass, of the dif 
ference between lead glass and lime glass, and of the 
reasons for the greater cost of lead crystal, will often 
sell the more expensive article. A few remarks re 
garding the manner in which metallic oxides produce 
color by fusing or firing make an interesting point; 
and even the " ringing " of a crystal goblet with its sil 
very tone adds to the value and attraction of the article. 


The process of melting, fusing, and forming glass 
is like a fairy story to those who have not heard it, 



Blown glass, for instance, has a new interest for cus 
tomers when they learn how it is made. Thus a 
knowledge of the various processes of manufacturing 
the different kinds of ware is an essential part of the 
commercial information of the salesperson. 

The salesman should understand the difference be 
tween cut, semicut, and pressed ware; acid polish, fire 
polish, and polishing on wheels. Etching, engrav 
ing, and carving should also be clearly understood, as 
well as the difference between needle-etching and plate- 
etching. Then the various methods of applying color 
and gilding are not only interesting but important, be 
cause of the greater durability of certain forms of 
decoration. Articles for mere ornament need not be 
so durable as those which are to be in constant use. It 
is therefore less unfortunate to have a vase with a dec 
oration which will soon wear off than it is to have 
water glasses with the same defect. 

Other Points of Importance to Customers 

An acquaintance with modern trade centers, both 
foreign and American, will give interest and authority 
to a salesperson's statements. Thus the distinct char 
acteristics of Venetian, Bohemian, Baccarat, and Bris 
tol glass have greater meaning when arguments can be 
based on definite information. 

Design is of special importance in glassware, and a 


cultivated taste is first of all necessary that one may be 
really helpful to the customer. Then, a knowledge of 
the particular designs belonging to any one period, 
such as the Colonial or the Jacobite, will be serviceable 
in aiding her to make a suitable choice. The names of 
the designs, especially in cut glass, should be learned 
and properly applied as they always attract attention 
and interest. The exclusiveness of a design gives it an 
added value to many customers, while standard pat 
terns of recognized merit will appeal to the more con 


It is estimated that two-thirds of the cut glass sold 
is intended for gifts. Thus the salesperson may often 
make a return or an exchange unnecessary by learning 
something of the purpose for which the article is in 
tended and the possible tastes of the person to whom 
it is to be given. These must often be mere guesses, 
but any clue may save some blunders. Thus, when a 
gift is to be made to one who " has everything," some 
thing of an exclusive design is more likely to please 
than a commonplace article which is likely to be a du 

Then, too, if tactful suggestions are made, gift 
buyers may select more expensive presents and be bet 
ter satisfied, because they feel that they have the right 


thing; while on the other hand some who have spent 
less than they had anticipated are thereby made per 
manent customers. 


Glass is usually arranged in as effective a manner as 
possible, so that its decorative value may be thoroughly 
appreciated. Single pieces as well as sets may, how 
ever, suffer from their surroundings and not be seen 
to the best advantage. It is often wise to place them 
in a corner where they have no more brilliant neigh 
bors to dull their beauty; or perhaps there may be 
pieces which will actually help to set them off. The 
value of proper surroundings is nowhere more evident 
than in a Glass Department. 


The glass on sale in a department should always be 
spotless and shining. The salesperson may give help 
ful information to customers as to the care of their 


The washing of glassware has much to do with its 
beauty. Glass is slightly acted upon by alkalies; 
therefore strongly alkaline soaps or washing powders 


will dull or scratch the surface. Water at the boiling 
point will also affect the polish. 

Glasses or pitchers which have contained cream or 
milk should be rinsed with lukewarm water softened 
with a little soda before being washed with the other 
pieces, as otherwise all the glass will have a clouded 
appearance. Water bottles or pitchers which have a 
deposit of lime on the inside may be cleansed by put 
ting in tea leaves, covering them with vinegar, and 
shaking the bottles. A teaspoonful of hydrochloric 
acid in a little water will also remove this deposit. 
The bottle should be rinsed immediately* 

Carbonate of ammonia causes flint glass to become 
brittle so that it will easily break and pieces will fall 

Glass should be washed in clean, warm (not hot) 
water, with a little white soap. Some housekeepers 
believe that it is cleaner when rinsed in water which 
contains no soap; others rinse in slightly soapy water 
and dry and polish on hot towels. 

Glass is often broken by pressure from the dish 
cloth or dish mop when washing the inside. The fol 
lowing suggestion is a good method for delicate cups 
or glasses : 

" Have enough water in the dishpan so that when 
the glass or cup is turned upside down it will be en- 


tirely full of water; now lift the glass quickly, still 
keeping it upside down and being careful not to tip it. 
It will remain full of water until it reaches the surface, 
when the rushing in of air will force the water out so 
suddenly that it will carry all food particles with it. 
This is an excellent method for washing sherbet and 
lemonade glasses." 1 

A writer in " Crockery and Glass " gives the follow 
ing suggestions for cleaning cut glass : 

" First make a warm soap-suds and wash the pieces 
with an old tooth-brush which will fit into the curved 
shapes and cut figures. Rinse in clear, warm water 
and wipe with a linen towel. After this polish with a 
warm towel and set in a box of sawdust for a few 
hours. The sawdust absorbs the moisture in the in 
cisions not reached by the towel, and also heightens the 
polish. When taken from the sawdust rub with a piece 
of tissue paper and the glass will sparkle like crystal/' 

Things to be Avoided 

Glassware should not be arranged in piles as it is 
heavy and brittle. Pieces are apt to be chipped off, 
and sometimes the lower pieces in the pile are cracked 
by the mere weight of those above. Such arrange 
ment is particularly unsuitable for cut glass. 

1 From Choice and Care of Utensils, by Ida S. Harrington, Farm House 
Series No. 5, Cornell Reading Courses. 


Glass should be protected against extremes of tem 
perature, such as cold storerooms or overheated chests. 
Very hot or very cold water, chilled or hot food, may 
cause it to crack. It should be tempered or warmed 
before putting in hot liquids, or cooled before filling 
with ice-cream. 

When boiling water or boiling syrups are to be 
poured into glass, the danger of breakage is lessened 
by putting in a silver spoon. 

Glass is very little affected by moisture, air, or light. 
Even after being buried in the earth for many years 
the only deterioration is an oxidation of the surface 
which shows in iridescent colors as in antique glass 
ware. Therefore with proper care and handling glass 
may be considered almost indestructible. 

Chapter XXI 



A. Tableware 

1. Cut Glass 

2. Pressed Glass 

B. Toilet Sets 

C. Decorative or Art Glass 

A Tableware 

i. Articles in Sets 

Grape Juice or Iced Tea 
Wine, Cordial, Liqueur, Cocktail 
Punch or Lemonade 

Mayonnaise or Whipped Cream 
Almond or Relish 
Sugar and Cream 



Single Articles 

Water Bottles 

Cruets for Oil, Vinegar, Catsup 





Whipped Cream 



Compotes or Compotiers 
Bonbon Dishes 

Ice-cream Platters 
Sandwich Plates 
Celery Trays 
Jam and Marmalade Jars 
Sugar Bowls 
Sugar Sifters 
Sugar Trays 
Salt and Pepper Shakers 
Spoon Holders 
Dinner Bells 
Toothpick Holders 


Knife Rests 

Syrup Jugs 

Fern Dishes 

Punch Ladles 

Salad Forks and Spoons 

Iced Tea Spoons 

Baking Dishes 


Cake, Pie, and Bread Pans 


3. Materials 






Metallic Oxides 




Rock Crystal 

4. Manufacture 







5. Decoration 



Silver Deposit 
Body Color 

Single Color 

Iridescent Colors 

Fire Colors 

6. Kinds 






B Toilet Sets 

1. Articles 

Night Sets 

Guest Sets 

Toilet Bottles 

Toilet Sets 

Puff Boxes 

Pin Trays 

Comb and Brush Trays 

Jewel Boxes 

2. Materials, Manufacture, Decoration, Kinds 

See 3, 4, 5, 6, under A 

C Decorative or Art Glass 

I. Articles 



Flower Bowls 

Flower Baskets 

Card Holders 


Pin Trays 

Comb and Brush Trays 

Jewel Boxes 

2. Materials, Manufacture, Decoration 

See 3, 4, 5, under A 

3. Kinds 

Same as A-6 



Glass Manufacture, Walter Rosenhain. Van Nostrand, $2 
Principles of Glassmaking, Powell. Geo. Bell & Sons (Lon 
Glass in the Old World, Wallace Dunlop. Field & Tuer 


Wonders of Glassmaking, Alexandre Sauzay. Scribner, $i 
Laboratory Guide of Industrial Chemistry, Rogers. Van 

Nostrand, $1.50 

The Glaziers Book, E. L. Raes. Maclaren & Sons (London) 
English Table Glass, Percy Bate, B. T. Batsford. Scribner, 

Decorative Glass Processes, Arthur Duthie. Van Nostrand, 


The Lure of the Antique, W. A. Dyer. Century, $2.40 

Marietta, Marion Crawford. Macmillan, $1.50 

Crockery and Glass Journal, Trade Journal 

International Studio, Special articles 

J. P. Morgan collection 

Development of Cut Glass Industry in the U. S., W. F. 

American Glassware, Old and New, E. A. Barber. Keramic 

Studio Pub. Co., $i 
Art of Glass, Neri 
Notes on the History of Glassmaking, Alexander Nesbit, 

Catalogue of Slade Collection of Glass, Felix ^f^^utS 
Reminiscences of Glassmaking, Deming James (only print) 
Principles of Glassmaking, Powell, Chance, Harris. Geo. 

Bell & Sons (London) 




ABBE, E. f 144 




marine plants near Venice, 182 

potash and soda, 12 
ALUMINUM, 16, 141, 143 
ANNEALING, 42, 184 

process, 42 
ARSENIC, 16, 141 



BACCARAT, 38, 188 


BARIUM, 16, 17, 143 


BATCH, 20, 21, 32, 33 



BEADS, GLASS, 51, 174, 184, 189 




BLANKS, 35, 55, 57, 60, 96 

battledore, 35 

blowpipe, 35 

glass blowpipe, 35 

measuring stick, 36 

pincers, 36 

shears, 36 

spring balance, 36 

tongs, 36 

working rod, 35 

glass, 35 

automatic machines, 38 
bottles, 47 
cut glass blanks, 55 
shaping stemware, 72 
Venetian, 109 

iron, 35, 36 

BLOWPIPE, 35. 36, 37. no 

characteristics, 114 

history, 115, 186 

medallions, 115 

methods of ornamentation, 114 

sources, 114, 186 
BORAX, 16, 17 
BOTTLE GLASS, 4,5. 60 

ancient, 180 

blown, 47 

made by automatic machines, 47; 49 
molded, 47. 48 
tear, 178, 185. 189 








CANDELABRA, 124, 131. 132 

CANDLESTICKS, 123, 131. *32, 138 


CANES, GLASS, no, in 



CHALK, 16 



143, 148 
COBALT, 141 


COLONIAL DESIGNS, 88, 124, 132 
COLORED GLASS, 17, 52, 103, 106, no, 



COLORS (See also "Bohemian," 
"Egyptian," "English," "Ro 
man," "Tiffany," "Venetian," 
etc., glass") 
pot metal, 115 




CROWN GLASS, 147, 148, iSS 
C TANK, 31 

CULLET, 22, 32, 142 

American, 62 
blanks, 55, 59 

CUT GLASS Continued 
characteristics, S3 
cut rock crystal, 63 
cutting wheels, 56 
designing, 55 
differences between English and 

American, 62 
English patterns, 62 
figured blank glass, 59 
floral patterns, 63 
judging values, 61 
labor cost, 57 
machines for cutting, 61 
materials, 54 
miter cuts, 62 
polishing, 58, 60 
process, 54 
roughing, 57 
smoothing, 58 
standard patterns, 88 
stone engraving, 56 
tracing the design, $6 


DECOLORIZERS, 9, 16, *4* 
acid-etching, 68 
colored, 96 

methods of ornamenting glass sur 
faces, 96 

appropriateness to use of article, 85 
cut glass, 86 

miter cuts, 62, 86, 87 
engraved patterns, 89 
form or shape, 83 
fundamentals , 83 
good, 92 

center of interest, 90 
composition of line, 9* 



DESIGN Continued 
pattern Continued 
elements of , go 
gradation, 91 
laws of , 89 
radiation, 91 
repeated patterns, 90 
symmetry, 91 
shape, importance of, 83 

cut and blown glass articles, 84 
use of color, 92 



beads, 174 

colors, 174 

first evidence of domestic use, 173 

glass porcelain, 175 

imitation stones and jewelry, 174 

mosaics, 174 

transparent blue, 174 
ELECTRIC LIGHT, 125, 126, 135, 136, 137 

daylight lamps, 136 

fixtures, 134, 135 

incandescent lamp, invention, 139 

shadowless lights, 136 

r29, 130 



ENGLISH GLASS (See also "Cut 

ancient, 189 

centers of cutting industry, 190 

colors, 191 

Druids, 189 

early factories, 190 

individuality, 190 

perfection of flint or lead glass, 190 


political history, 191 

tableware, 191 


needle-etching, 67 

plate-etching, 68 

sand-blast etching, 68 


PAVRILE GLASS, 117, 120 
FINING, 33, 143 

annealing, 42 

gathering, 34 

molding, 41 

polishing, 44 

pouring, 34 

sadling, 34 

varieties of kilns, 43 
FIRE POLISH, 44, 46 
FLASHED GLASS, 106, 114. 156 
FLINT, 6, 10 

FLINT GLASS, n. 185, 190 
FLUXES, 12, 33 

Baccaret crystal factories, 188 

D'Artiques, 188 

Frontencennea, 187 

painted windows, 188 

plate glass casting, 188 



FRIT, 22, 32 
FROSTING, 63, 69, in 

ancient Venetian, 182 

calcar, 31 

construction, 23 

C tank, 31 

fire clay, 27 

fuels, 24 

kinds, 23 

manufacture of pots, 28 

pot furnaces, 25 

tank furnaces, 29 



fixtures, 132, 133, 134 
history, 139 
illuminating, 125, 139 
lamps, 126 
mantles, 134, 139 
GATHERING GLASS, 34, 37, 38, 4*t 48, 

55, 72, 106 

gold banding, 97 
gold leaf, 97 
gold resist, 96 

beauty, 3, 4 
durability, 3, 4 
utility, 3 
divisions according to composition, 


nature of (See "Nature of glass' 

early experiments, 192 


growth of, 194 

improvements in furnaces, 196 

invasion of foreign markets, 195 

pioneer concerns, 193 

Pittsburgh and the Middle West, 

pressed lime glass, ^95 

display, I 

divisions of department, 2 



"Bohemian," "Egyptian," 

"English," ** French," '* Roman, '' 
and "Venetian Glass") 

ancient varieties, 178 

Assyrian, 175 

Bohemian, 186 

"Christian glass," 181 

early art in France, 187 

Egyptian, 173 

English, 189 

Grecian, 177 

modern development, 185 

oriental countries, 175 

Persian, 176 

Pompeii and Herculaneum, 180 

Roman, 177 

Spanish, 185 

Theban, works of art, 175 

Venetian, %8i 




IMITATION GEMS, n r 52, 175, 178 
INCANDESCENT LAMPS, 134, 135, 136 

invention, 139 

antique glass, 119, 179 
modern glass, 104, 105, 118 

JARS, 77 


KELP, ii, 13, 14 

KILNS, 43 
intermittent, 43 


development in U. S., tests, 149 

Jena glass, 149 

materials, 149 

resistance to acids, alkalies, shock, 
etc., 148, 149 

thermometers, 150 

uses, 148 
LADLING, 34, 35, 118 
LAMP STANDS, 128, 138 
LAMPS, 125 

adjustable, 127 

electric, 126, 127 

floor, 128 

LAMPS Continued 

gas, 126 

history, 137 

oil, 125, 126, 139 

portable, 126 

student, 126 

table, 127 

glass, 130 

metal, 129 

parchment, 130 

porcelain, 130 

textile, 13*0 

automobile, 133 

feast of , 139 

Qhinese and Japanese, 138 

history, 138 

oriental, 133 

ships', 133 

LEAD, 6, 11, 15, 17, 18, 52, 54 

construction, 154 

kinds of glass used, 155 
LBHMANN, CASPAR, 114, 186 
LEHRS, 42 

continuous, 43 

difficulty, 145 

Yerkes and Mt. Wilson telescopes, 


automobile, 51 

compound, 147, 148 

concave, 147 

convex, 147 

cylindrical, 147 

eyeglass, 147 

gas mask, 51 

lighthouse, 147 

magnifying, 147 

microscope, 147 

mirror, 80, 146 



LENSES Continued 
periscope, 145, 146 
photograph, 146, 147 
spherical, 147 
testing, 148 

LlEBIG, J., VON, 79 


daylight glass, 136 

fixtures, 125, 133. 135 

illuminated, 125 

indirect, 135 

semi-indirect, 135 
LIME, 6, ii, 15, 59, 108 

chalk, 16 

crystal, 59 

gypsum, 1 6 

limestone, 16 
Low COLOR, 45 



fusing and fining, 22, 32 

mixing the batch, 21 

preparation of sand, 20 
MARVERING, 37, no 

MATERIALS, GLASS, 5, 54, 108, 114, 
118, 176 (See also "Lead, 1 * 
"Lime," "Potash," "Sand," 
"Soda," and "Coloring ma 

METAL, GLASS, 34, 46, 93 



MIRRORS, 79. 82, 130, 184, 188, 190 

amalgam, 79 

platinum, 81 

silvered, 80 
MOIL, 39 
MOLD, 39, 41 

blank, 49 

finishing, 49 

measuring, 48 

neck, 49 
MOLDING, 41. 48 


MURANO, 43, 108, 182 


115, I74 I75 178, 180, 186, 189 

a neutral salt, 8 

artificial mineral combination, 5 
different from precious stones, 6 
possibilities for artistic treatment, 

viscosity, 5, 34 




OIL LAMPS, 125, 126, 138, 139 





American, 145 

during World War, 145 

furnaces and crucibles, 142 

Jena glass, 144 

manufacture, 143 

materials, 142 

power of resistance, 143 

requirements, 140 

veins or striae, 14** I44f 1 4S 
OVENS (See "Furnaces," "Kilns") 
CHINE, 49, 146 

PATERA, 179, 181 
PEARLASH, xx, xa 
PITCHERS, 77, 85, 87 

casting, 188 

figured, 152 

polished, 152 

rolled, 151 
PLUNGER, 39t 40, 48 

acid, 44, 60 

cut glass, 58 

mirror, 80 

silver deposit, 100 
PONTIL, 48, 72 (spe also "Punty") 
POTASH, 6, xo, 12, 54, 80 

American, 13 

POURING, 34, 35, so 


TORIES, 187 

different from glass, 6 

imitations in glass, n, 52 
PRESSED GLASS, 38, 40, 44, 46 
PRISMS, 62, 132, 146, 147 
PUNTY, 38, 72 (See also "Pontil") 


crystallized silica, 10 

flint, 10 

rock crystal, 64 


RED LEAD , 15 
RESIST, 67, 68, 70 

gold, 96 % 
ROBINET, M., 38 

ancient lens, 176 

collections, 65 

cut, 63 

cutters, 187 

for lenses, 147 

genuine, 64 

works of art, 64 

amphora and ampullas, X79 

" Christian " glass, 181 

color effects, 178 

crystal, 179 

factories, 177 

many designs, 178 

patera, 179 

Portland vase, 180 






arrangement of stock, 203 
care, 203 

cleaning glassware, 203 
knowledge of manufacture, 199 
points of importance to customers, 


qualifications for selling glass, 199 
suitability, 201 

Chile, 14 
SAND, 6, 7, ", 54, i*4. *7<5 
preparation, 20 
sand beds, 9 
sandstone, 10 
SCHOTT, O., 144 
SEAWEED, n, 14. *?6 

almond, 76 

bedroom and toilet, 76 

berry, 75 

finger-bowl, 75 

flower, 76 

grapefruit, 75 

grape- juice, 75 

iced tea, 75 

mayonnaise or whipped cream, 76 

punch and lemonade, 75 

sherbet, 75 

sugar and cream, 76 

water, 74 

wine, 75 




SILICA, 6, 10, n, 54.64 


engraving, 101 

original process, 101 

process of manufacture, 98 
SILVER STAIN, 105, 156, 167 

cut glass, 58 

silver deposit, 100 
SODA, ii, 12, 14. 108 

Chile saltpeter, 14 

salt-cake, 14 
SODA- ASH, 14 
STAINED GLASS, 105. *59 

antique, 161, 162 

definition, 159 

design, 159, *6o, 161, 165, 170 

enamel painted, 160 

flashed glass, 164 

opalescent, 160 

plated, 160 

silver stain, 167 

types, 1 60 

Venetian, antique, 164 
STARS. 62 



bell-shaped, 73 
drawn, 73 
ovoid, 73 
straight-sided, 73 
variety of, 72 

shaping, 72 

the "boss," 72 





STRIAE, 141, 144 




TAZZA, in 



TELESCOPE Discs, 80 

MAKING, 146 
TIFFANY GLASS, 117, 130 

characteristic colors, 117 

meaning of Pavrile, 120 
TRAILING, 70, 73, 105, 109 

limited by coloring materials, 141 
TUMBLERS, 74, 190 


Portland, 180 

Sargon, 175 

lamp, 128 

ornamental, 132 

table, 7, 122, 

varieties, 121 

American reproductions, 93, 113 

beauty of design and color, 92, 107, 



composition, 108 

curious shapes, 108 

examples, 113 

mirrors, 184 

process of formation, 109 

tools, 183 

varieties, nr 
VERRE DE SOIB, 103, 104 


WINDOW GLASS, 151, 155, 159 

antique glass, 161 

casement, 153 

design for stained glass, 170 

double hung, 152 

effect of finished window, 169 

enamel painted, 160 

English casement, 154 

French, 153, 188 

opalescent, 161 

Stained glass, 159, 164 
WORKING HOLE, 29, 10,9 


ZINC, 17 



1 04 390 

03 <