GLASS
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_Reprinted June, 1918._
_Reprinted June, 1919._
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[Illustration:
AN OLD GLASS HOUSE, A.D. 1790
_Frontispiece_
]
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_PITMAN’S COMMON COMMODITIES
AND INDUSTRIES_
GLASS
AND GLASS MANUFACTURE
BY
PERCIVAL MARSON
CONSULTANT UPON REFRACTORY MATERIALS, ETC.,
HONOURS AND MEDALLIST IN GLASS MANUFACTURE.
LONDON
SIR ISAAC PITMAN & SONS, LTD., 1 AMEN CORNER, E.C.4
BATH, MELBOURNE AND NEW YORK
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PRINTED BY SIR ISAAC PITMAN
& SONS, LTD., LONDON, BATH,
NEW YORK AND MELBOURNE
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PREFACE
Who is not acquainted with glassware in some form or other? From the
early days of the Ancient Egyptians the art of glassmaking was known,
and it is now one of our most important industries, supplying as it does
many articles for our common domestic use and convenience. Glass windows
have introduced comfort and convenience into every home; for by their
means light is admitted into our dwellings without the wind, rain and
cold, and we enjoy the blessings of the one without the inconveniences
of the others. The purposes for which glass can be used are manifold;
and in domestic articles it contributes largely to our cleanliness and
health. In the use of spectacles, table glass, mirrors, bottles, and
many other goods our dependence upon glass becomes very evident. The
degree of proficiency attained in the manufacture of glass is still more
remarkable when we consider the various kinds of glassware used in
physical, chemical, astronomic, medical, and other scientific
investigations. Many of the wonderful results of the present times would
not have been attained without the aid of glass in supplying the needs
of our scientific investigators. Before August, 1914, few people
realised the important part glass occupies in the production of war
munitions. The importance of optical glasses for telescopes, gun sights,
and microscopes is well known. Again, glass plays an essential part in
every ship, locomotive, motor-car, aeroplane, and coal mine, and if
defective glasses were supplied there would be a great loss in our
industrial efficiency. The manufacture of high explosives or special
steels could not be carried on without the supplies of laboratory
glassware to enable the chemist to carry out his delicate tests.
Upon the outbreak of the present war our supplies of certain types of
glassware were not made in Great Britain, but imported from abroad, and
it was owing to the energy and enterprise of a Scottish glass
manufacturer, with some assistance from a well-known scientist, that a
start was made in making these much-needed goods, and what might have
been a serious crisis was averted. Professor Herbert Jackson and the
Institute of Chemistry placed at the disposal of glass manufacturers
numerous formulas for the special glasses that were urgently required,
and later on this work was recognised by the Government; and now the
investigations are being continued by a committee, with the assistance
of the Government, under the control of the Ministry of Munitions. This
committee is now rendering the greatest assistance to manufacturers in
the general development of the glass trade and the reclamation of the
ground lost in previous years. There is now every hope that Britain may
raise again to eminence and perfection this very important industry of
glassmaking. One of the chief objects of this volume is to supply within
a small practical treatise the general available information upon glass
manufacture, much of which, although familiar to many manufacturers or
those engaged in glass works, will be of great assistance to those who
are commencing a study of this very interesting and complex subject.
Few people have any idea of the vast and enormous trade done on the
Continent in the manufacture of glassware for export to Great Britain
and British Possessions abroad, and on this account it is essential that
so important a subject as glass manufacture should form some part in the
technical education of our universities and trade schools, so that a
section of the rising generation may be taught to understand the
manufacture of such a necessary commercial product, and assist in
recapturing the trade from the Continental glass works in supplying our
needs. That some progress has been made along these lines is evident by
the establishment at Sheffield University of a school in Glass
Technology, and it is to be hoped that similar schools will be
established in other centres, staffed by capable instructors and
supported by the co-operation of the glass manufacturers.
The author gives in an Appendix the literature accessible to those who
wish for further information upon the subject, and trusts that, in the
presentation of these notes, in response to the demand for such a book,
a useful purpose will have been served by introducing the first
principles of glass manufacture to those interested.
It affords me great pleasure to acknowledge the valuable aid that has
been rendered me by Mr. S. N. Jenkinson, Professor Herbert Jackson, and
Mr. Frederick Carder, to whom I am much indebted.
My thanks are also due to the following firms: Messrs. Melin & Co.,
Crutched Friars; The Hermansen Engineering Co., Birmingham; The Glass
Engineering Co., Edinburgh; and Banks & Co., Edinburgh, who have kindly
supplied me with illustrations.
PERCIVAL MARSON.
CRAIGENTINNY,
EDINBURGH.
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CONTENTS
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CHAP. PAGE
PREFACE V
I. HISTORY 1
II. THE CHEMISTRY OF GLASS-MAKING AND THE 4
MATERIALS USED
III. THE CHEMICAL AND PHYSICAL PROPERTIES OF 15
GLASS
IV. THE COMPOSITION OF THE DIFFERENT KINDS 24
OF GLASS
V. COLOURED GLASS AND ARTIFICIAL GEMS 28
VI. DECOLORIZERS 32
VII. THE REFRACTORY MATERIALS USED 36
VIII. GLASS HOUSE FURNACES 43
IX. GLASS-MELTING POTS AND THEIR MANUFACTURE 59
X. LEHRS AND ANNEALING 71
XI. THE MANIPULATION OF GLASS—GLASSMAKERS’ 76
TOOLS AND MACHINES
XII. CROWN, SHEET, AND PLATE GLASS 89
XIII. TUBE, CANE, AND CHEMICAL GLASSWARE 96
XIV. OPTICAL GLASS 104
XV. DECORATIVE GLASSWARE 108
XVI. ENGLISH AND FOREIGN METHODS OF GLASS 118
MANUFACTURE COMPARED
APPENDIX 123
INDEX 125
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LIST OF ILLUSTRATIONS
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PAGE
AN OLD ENGLISH GLASS HOUSE, A.D. 1790 _Frontispiece_
HORIZONTAL CRACKING-OFF MACHINE 1
INTERIOR VIEW OF AN ENGLISH 44
GLASS-MELTING FURNACE
EXTERIOR VIEW OF AN ENGLISH 46
GLASS-MELTING FURNACE
SIEMENS SIEGBERT REGENERATIVE
GLASS-MELTING FURNACE—
FIG. A. CROSS SECTION 48
FIG. B. SECTIONAL PLAN 49
Fig. C. SECTIONAL ELEVATION 50
A MODERN GLASS HOUSE. HERMANSEN’S 52
CONTINUOUS RECUPERATIVE GLASS-MELTING
FURNACE, COVERED POT TYPE
HERMANSEN’S CONTINUOUS RECUPERATIVE 53
GLASS-MELTING FURNACE, 8-POT TYPE
HERMANSEN FURNACE—
FIG. A. SECTION THROUGH GAS PRODUCER 54
FIG. B. CROSS SECTION THROUGH GAS 55
PRODUCER
FIG. SECTIONAL PLAN 56
“THE HARLINGTON” BOTTLE-MAKING MACHINE 79
GLASS WORKER’S CHAIR 81
GLASSWARE BLOWN IN MOULDS, FIG. A. AND 85
B.
VERTICAL CRACKING-OFF MACHINE 87
FOUR STAGES IN CROWN GLASS MAKING (A, B, 90
C, D)
SIX STAGES IN SHEET GLASS MAKING (A, B, 91
C, D, E, F)
MACHINE FOR SMOOTHING BOTTOMS OF 110
TUMBLERS
GLASS ENGRAVING 113
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GLASS AND GLASS
MANUFACTURE
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CHAPTER I
HISTORY
The discovery of making glass is attributed to the early Phoenicians.
Pliny relates that certain mariners who had a cargo of soda salt, having
landed on the banks of a river in Palestine, started a fire to cook
their food, and, not finding any stones to rest their pots on, they
placed under them some lumps of the soda from their cargo. They found
that the heat of their fire had melted the soda and fused it with the
sand of the river bank, producing a transparent glass. The natives in
the vicinity where this discovery was made in process of time carried on
the practice of fusing sand with soda and other materials to make glass,
until they succeeded in improving and bringing the art to a high degree
of excellence. Discoveries amongst the ruins of Pompeii and Herculaneum
present some first-rate examples of the skill attained by the ancients
in glassmaking: glass was found to have been used there, admitting light
into dwellings in the form of window glass.
The ancient Egyptians have left us many distinct proofs that glassmaking
was practised in Egypt. At the same time, the glazing of pottery was
also carried out, proving that they knew the mode of mixing, fusing, and
melting the proper ingredients for glassmaking. Among the tombs of
Thebes many specimens of glass and glazed pottery beads have been found,
which suggests a date about 3,500 years ago.
From the Egyptians, the Greeks and Romans acquired the art of
glassmaking, which in Nero’s time was so highly developed that clear
crystal glasses were produced in the form of drinking cups and goblets,
which superseded the use of gold cups and were much prized by the
Emperor in those days.
Many specimens of old Roman glass discovered have been preserved in the
British Museum, and, although many valuable pieces have been lost by
disintegration and collapse due to the influence of years of exposure,
there still remain some very fine examples which show that the Romans
were highly skilled in glassmaking. One of the finest examples of the
work of the ancient Romans in glassmaking is the Portland Vase, which
was unearthed near Rome. This is an ornamented vase showing white opaque
figures upon a dark blue background. The white opal appears to have been
originally cased all over the blue and the beautiful figures carved out
in cameo fashion, with astonishing patience and skill upon the part of
the operator.
The Venetians and Muranians followed the Romans in the art, and examples
of old Venetian glassware show rare skill and ingenuity. To the
Venetians belongs the honour of first making glass at a cost to allow of
its being more generally used, and they also introduced the art of
making window glass and drinking vessels into this country. Jacob
Verzelina, a Venetian, introduced such glassmaking into England, working
at a factory in Crutched Friars, London, between 1550 and 1557, where he
made window glass, afterwards carrying on similar work in other places
about the country until his death in 1606.
Not until 1619 were glass works started in the neighbourhood of
Stourbridge. There we find some remains of a factory worked by Tyzack
about that date in making window glass in the village of Oldswinford.
That Stourbridge should have been selected as one of the early centres
for glassmaking is probably due to the presence in that locality of the
so necessary and important to glass manufacturers in building their
furnaces and pots, and the coal used for maintaining the fires for
melting their glass.
Stourbridge was known for a long time before this as a centre for the
mines producing , and eventually this clay was adopted for making
glass-house pots; now many other sources are available for these
fire-clays. Much of the antiquity of the glassmaking of England is
hidden in the neighbourhood of Stourbridge, and the writer has himself
found a few antique specimens of old green devitrified window glass
embedded in the subsoil of some fields near Oldswinford, probably relics
of the Huguenots, who practised and extended the art of glassmaking in
that district. Other important centres for glassmaking now are York,
London, Manchester, Edinburgh, Newcastle, and Birmingham; but, although
glassmaking has reached a high degree of excellence in this country,
there is nothing yet comparable with the extensive factories which exist
abroad. The conservatism of many English manufacturers, and the adverse
influence of the Glass Makers’ Society, considerably restrict the
progress of this trade compared with the broad and progressive manner in
which it is carried on abroad.[1]
Footnote 1:
_See_ article “Trade Unionism,” in last chapter.
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