Glass blowing, Agricola, De re metallica. 16th C Credit: Wellcome Library, London. http://wellcomeimages.org
by J. C. Harrington Reprinted from The Chronicle, Volume X, No. 1, March 1957
Since the Spring meeting of the Early American Industries is to be held at the Corning Glass Center at Corning, New York, the Editors of the Chronicle felt that it would be appropriate to devote a considerable amount of space in this issue to the first real American Industry, glass manufacture. The operation that the visitor sees today at the Steuben Factory at Corning is in many respects comparable to the operational steps first utilized at Jamestown, Virginia shortly after the first permanent English settlement in the new world was established at that site in 1607.
Because 1957 marks the 350th anniversary of the settlement at Jamestown and because the reconstruction of the first "Glass House" on Glass House Point near Jamestown is one of the many phases of the 350th anniversary celebration, the Editors contacted Mr. J. C. Harrington in relation to an article for this issue. Mr. Harrington is the Eastern Regional Archeologist for the National Park Service and was instrumental in the investigation of the original site of the first Glass House and its eventual reconstruction. The Glass House near Jamestown will be open to the public April 1, 1957. Mr. Harrington is the author of a brief publication entitled, "Glassmaking at Jamestown", which was prepared as part of the glassmaking study being carried on by the National Park Service of the United States Department of the Interior and Glass Crafts of America.
Soon after starting archeological excavations at the Jamestown glasshouse site in 1948, a visitor asked what we expected to find. As I recall, my answer was "probably remains of the furnaces, some broken glass, and possibly some of the glassmakers' tools." These are the kinds of things the archeologist expects to uncover when he digs; this is the evidence he uses to reconstruct the original scene and the things that happened there. At the site of the Jamestown glass factory we found the ruins and the broken glass, but no tools. In addition, a great deal of other information came to light which showed quite clearly what the original furnaces looked like and how they were used. Enough pieces of broken melting pots, for example, were found to enable us to reconstruct several and to count at least twelve separate pots. On every hand was ample evidence that glass had been made there in considerable quantity. The size of the wooden structure housing the operation was revealed; a water well was found at one corner of the building; charcoal and ashes showed the kind of fuel used. In fact, enough evidence was uncovered to permit an entirely satisfactory reproduction to be built near the original foundations. This reproduction will be in operation throughout most of each year, with costumed glass blowers making little pale green bottles and other objects, just as similar objects were made when the factory began operation under the direction of Captain John Smith in the fall of 1 608. *
Disappointed as we were in not finding the traditional blow pipes and other standard glassworkers' tools, at least we were confident we would have no difficulty in determining what implements were used and what they looked like. For one thing, it is firmly believed, and with justification, that the equipment used in making glass by non-machine methods has changed very little during the past few centuries. Glassworkers will say "Why my grandfather and his grandfather used tools just like the ones we use today." On the whole, this is true, but like all craftsmen's tools, changes from generation to generation do occur, although they are often too slight to be apparent unless some entirely new implement is developed.
More reliable information was needed, however, and for this we turned to contemporary descriptions and pictures. They are by no means plentiful, but those available are fairly satisfactory. The earliest reliable source is Agricola's chapter on glassmaking in his book on mining. His several views on the interiors of glass houses, one of which is reproduced in this issue, shows a number of glassmaking tools, as well as the conventional equipment of a glass factory of the mid-sixteenth century. Publications on glassmaking for the next two centuries, or more, copied Agricola's illustrations, and with very little change except for the workmen's clothing. For example, Blancour's treatise, published at the end of the seventeenth century, shows a view in a glasshouse almost identical to Agricola's. Far more important for the purpose of reconstructing the Jamestown glasshouse, Blancourt's work contains an excellent illustration and description of glassmaking tools.
For the century and a half between Agricola and Blancourt, there is no good source for glassmaking tools. The only detailed publication on glassmaking during the period is Neri's L'arte vetraria, published in 1612. Unfortunately, Neri dealt primarily with' materials and the art of fabrication. Such things as tools were apparently considered everyday matters familiar to every glass worker. Merret's excellent translation of Neri's work, published in 1662, adds new material on furnace construction and operation, but does not tell us much about the workmen's tools.
Actually, this void is not as serious as one might at first think. Comparison of Blancourt's illustrations with Agricola's shows that the conventional glasshouse equipment, except for certain possible changes in furnaces and melting pots caused by the introduction of coal as fuel and the invention of lead glass, did not change materially during this relatively long period. It was not too difficult, therefore, to design the tools that the Jamestown glassmakers were likely to have used. The major ones are shown herein and described in more detail in my booklet, Glassmaking at Jamestown.
In addition to those shown, the Jamestown workmen probably also had one or more wooden tools for smoothing and shaping glass objects. They may also have had some simple open-top "dip" molds of brass, used for giving bottles and tumblers their basic shapes and imparting the ribbed or writhen surface, popular at this time. There would also have been a stone slab, probably of marble, known as a "marver," on which the initial "gather" of glass was rolled. And, of course, there were wooden buckets and tubs for water, barrels for shipping the finished products, a wheelbarrow or two, and other auxiliary implements, such as shovels, axes, sledges. wedges, and such. Examples of these less specialized tools have been found in abundance in the excavations at the townsite on Jamestown Island, a mile from ·the glasshouse site. But thus far, not a single fragment of a glassblower's special tools has been identified among the thousands of iron objects recovered in the excavations on the Island.
Comparing our conjectural reconstructions of the glassmaking equipment of 1608 with that used in a modern glass factory where glass is still made by the old hand method, we do, in fact, see few differences. The blow pipe and punty rod today are somewhat longer. One principal difference in the blowpipe is that the early ones were partially covered with wood or other material, as shown in the old drawings. This was possibly necessitated by their shorter length.
Today the craftsman uses a far greater variety of tools, although he still relies primarily on a wood paddle (battledore), wooden "block" for shaping, and iron pincers, shears, and scissors. Today's "chair" usually has longer arms, but this is only because larger objects are blown, necessitating a greater rolling space for the punty rod. The "marver" today is steel, rather than stone, and there are other concessions to more permanent materials. But the glass worker today who says that the tools of his craft have remained unchanged is essentially right. Mostly, he has added to his assortment rather than making any drastic changes in the basic equipment.
Just as today's craftsman is able to step back 350 years in to the reconstructed glasshouse a t Jamestown and make glass in the manner of 1608, so one of the original Jamestown workmen, if he should miraculously come to life, could quickly adapt himself to a modern glass factory. His biggest surprise would probably be the shorter hours, the coffee break, and the music blaring mysteriously from a little magic box overhead.
* The site is located on Glass House Point near the Colonial Parkway in Colonial National Historical Park. Construction of the reproduced glasshouse and its operation as an educational exhibit is a joint project of the National Park Service and the American Glass Industry.
Notes On Glass Blowing
The information contained in these notes was extracted from "Glassmaking at Jamestown", by Mr. J. C. Harrington, National Park Service. This pamphlet was printed in 1952 by the Dietz Press of Richmond, Virginia. This publication was prepared as part of the Jamestown glassmaking study carried on jointly by the National Park Service of the United States Department of the Interior and Glass Crafts of America.
Three types of furnaces were used at Jamestown; a kiln for firing new pots and preheating pots before being placed in the working furnace; a furnace for "fritting"; and one for annealing, called a "lehr" or "leer".
The composition of glass largely consists of silica, which occurs most commonly in sand. The materials added were mainly soda and lime, with potash sometimes substituted for soda, or used along with it. These are known as "flux" today, but at Jamestown were called "salts". Until lead glass was developed in England in the late 17th century, glass was made from these basic ingredients. A final ingredient was old glass, or "cullet" which was probably gathered up around the settlement for the first operations and later accumulated from waste glass around the glass house.
Besides the actual blowing of glass two other operations required considerable skill. The first was that of "Fritting", on the preliminary partial fusion of the raw ingredients with the resulting product called "frit". This was performed in a furnace known as a "cakar", and the workman was known as a "founder". To make "frit", the sand lime, potash, and soda were thoroughly mixed and shoveled onto the ledge at the back of the "calcar". As the heat of the furnace rose, the "founder" stirred the mixture and worked it over with a long-handled rake or hoe. As soon as this semi-fused mixture reached the proper stage, it was quickly pulled out of the furnace onto a stone platform, and, after cooling, was broken up and stored for future use.
The second skilled operation was the making of melting pots. The break-up of these pots were enormous due to the intense heat which caused the pots to start to soften and the corrosive action of the glass which ate into the pot and eventually destroyed it. A proper clay was used, and as in brick making, underwent a lengthy treatment before ready to mold. When finally molded, it was placed in the kiln.
The fire was re-started in the furnace and the proper combination of "frit" and "culler" placed in the pots. As the "bater" melts more ingredients were added, until about a full working day the pots were fully charged. During this early stage of melting, the material was stirred with a special iron rake. Impurities rose to the surface causing a white spongy scum to accumulate. This "sand Gall", or "sandever", was removed at once with an iron ladle, and as one writer stated, the master-workman has "to scum the Sandever, and dross, from the pot wherein he worketh". Gradually the heat of the furnace increased until finally, after another day, vitrification was complete and a true glass had been achieved. Fire was then slackened just enough so that the molten mass was at the right temperature for working. Fires also had been started in the annealing furnace so that they would be ready to receive the completed glass.
An experienced worker known as the "servitor" collected the blot of glass – called the "gather" – on the end of a hollow iron tube, called a "blowing iron". While it was hot the "servitor" rolled it to and fro on a marble slab so that it might be firmly united; and then gently blew into the hollow iron raising the molten glass. In order to lengthen and cool the glass during the blowing he several times raised the iron above his head and whirled it about. While the "servitor" had been giving the glass (called the paraison at this stage) its general shape, the master workman had made a small "gather" on the end of another iron tool, called a "ponteglo" or "ponte". This is simply a solid iron rod, shorter than the blowing iron, and slightly enlarged at the end so that the "gather" will stick to it better. By means of this second "gather" of molten glass, the "ponte" was attached securely to the "paraison" by pressing the new "gather" against the end of the "paraison" exactly opposite to the point where it was still attached to the blowing iron. The "paraison" was then cracked or cut from the blowing iron. By this time the glass having cooled too much to work, was held in the working hole (glary hole) of the furnace and brought back to a workable temperature. The master workman then went to his "chair". This is a sort of wooden bench with flat arms extending out in front of the seat. Seated in the chair, the master workman rolled, or trundled, the "ponte" back and forth over the arms of the "chair", and at the same time widened, constricted or otherwise shaped the pliable glass until the desired form was achieved.
During the process he might have had to re-heat the glass several times. As the finished glass article was still very hot and had to be cooled gradually to give it the necessary final strength, the workman removed it from the "ponte" by giving the "ponte" a sharp blow. One of the helpers then carried it to the annealing oven, or "leer" using a forked stick or a two-pronged iron rod. The objects were stacked in a compartment at the back of the "leer", and when the space was filled the opening was blocked up and the fire allowed to go out. The gradual cooling of the stone structure produced the desired annealing effect. In two or three days the "leer" was opened and the articles removed.