الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
It is necessary for one who wishes to grasp successfully
the principles underlying the process for the production of glass
on large scale to possess some knowledge of the sciences upon
which glass technology is founded.
The chemical knowledge upon which the making of good glass
depends is fundamental, but, until recent years, has been sadly
neglected. It has been the custom to construct batches from for-
mula handed down from generation to generation, and often jea-
lously guarded, but no knowledge of the changes involved durirtg
the process of manufacture was deemed necessary. As a result,
when slight deviations from the normal conditions occured, usually no one was available who could set matters right, and difficulty and even disater followed. It may be cited, for instance, the
variation of composition of the batch materials. It is now known
that a small change in the proportion of certain substances pre~
sent, in the glass (i.e., iron oxide, alumina, Sbz03, etc.) makes great differences in the appearance or properties of the product
obtained. Ag?in, variations of moisture content in batch materials
may affect substantially the amounts of the various oxides enter¬ing the glass, and their ratio to one another.
To one versed in chemistry the variations indicated are at once seen to be vital; they can be determined by anyone possess¬ing Cl knowledge of chemical analysis, and, when this is done, the batch can be altered accordingly, so that the glass may remain
cons tan t in compos it ion. The older glas s manufac turc’ 1’S were a 1 so
entirely at the nlercy of those who provided them with materials,
and even ln cases where substances of good average purity were
regularly supplied, it was not impossible, and even probable, that
ow and again compounds unfit for use, from the point of view of
purity, were delivered. In general, no means but those of chemi¬cal analysis ~ould serve to detect and reject the faulty materials.
Where, in spite of precautions, difficulties actually occur (in this category devitrification and the production of stony metal) through inefficient batch-mixing, too Iowa temperature of
founding, or attack on the refractories, one who is equipped with some chemical knowledge will be more likely to get to the root of the trouble than one who is totally unversed
An understanding of the structure of various mat~rials, ref-
ractories as well as batch, metals and extraneous ones, and their
reactions during the glass making process makes it possible to
define the source of glass defects, generally or specifically in
Egypt. Stones and cords will remain a muisance to everyone con-
cerned with the glass melting process, because frequently neither
the cause of the defects, nor its remedy can be dealt with ade~
quately.
For stone problem to be solved more is required than just
the identification of the crystalline contents, the essential interest in the problem concerns the source of its origin and
the question what technological action in the glass-melting pro¬cess will lead to its solution. Some knowledge of what had hap¬pened from the source until the ultimate condition in which the
stone is found, in brief the historical development, is of very
important. Concequently the microscopic image will have to be