Glass manufacturing was a closed occupation in Medieval Europe concentrated in Venice and closely guarded by the guild and Italian authorities of the time. Glass making requires high temperatures and therefor a fired furnace. Traditionally with wood. Given the risk to adjacent buildings the Venetian authorities centred glass making on the Island of Murano. This provided increased security of the trade secrets but also stifled development of the art further. Crude light green glass was also made in forests of Germany ‘waldglass’. But the big changes developed in England in the early 17thC and cider played its role as a stimulus. Several Italian glassmakers were already operating in England by this time, a key one being Jacob Verzelini from Murano and set up a furnace in London. He needed Royal protection being an alien and achieved this in 1574. The terms including a clause requiring him to instruct Englishmen in the art. Forest glass makers were also active especially in the Weald. The first successful English glass maker to obtain a royal warrant was was William Robson who by 1610 was in control of the crystal glass market. He took over the glass furnaces from an other Englishman Salter at Winchester House London, a glasshouse that features large in the development of glass bottles. By the late 16th C wood shortages were becoming a problem in Elizabethan life. The early industrial revolution of iron and glass making was competing for wood with traditional industries such as shipbuilding and domestic use eg. even in Henry VIII’s reign laws were enacted for 12 ‘standills’ or tall trees to left standing on each acre of woodland cut over. This led to a major change in the glass industry; the change to coal. However that was not a simple process, coal burns at a higher temperature and required changes in the composition of the ingredients. Which was difficult as the science of glass making was largely unknown, the ‘recipes’ being handed down in families as closely guarded secrets. Breakthrough finally came for a consortium . The patentees included courtiers Sir Edward Zouch and others in the trade including Thomas Percival to whom the invention as attributed. This was bitterly opposed to those including Robson who made glass from wood. Robson was on the losing side but entered protracted litigation over the next 15 years! However the Winchester furnaces were in the hands of Zouch by 1612 and converted to coal.
The company grew and by the time of his 3rd extension in 1615, 5 new patentees were included including Mansell. His history is interesting; a younger son of an old family he climbed the ladder of Royal patronage by first entering the Navy aged 15 and showed great bravado in battle earning a knighthood and by 1603 was the Vice Admiral of the Narrow Seas. He then become land based as Treasurer of the Navy where he combined his fiery temperament with his zeal for advancement and had been interested in several speculative ventures before glass. Mansell was an excellent recruit to the Zouch syndicate as he he took a more vigorous leadership as is his character. He has been described as a Welshman with the manners of an Admiral and the brains of a financier”.
At this point a new but pivotal name appears in the story. James Howell another Welshman who ended up writing a history of James II, as the manager of the Broad Street glassworks. He did not survive long as a manager but learned the trade and history well.
The company under the control of Mansell gradually overcame all opposition and despite heavy losses fighting law suits against the monopoly and investment needed in coal glass production made a modest return. The end of the Monopoly came in 1642 when the Parliament cancelled the Royal patent on grounds that the King did not have the right over Parliament. This was just one of the grievances that led to the Civil war. However by then the coal process was well established and reverting to wood was no longer a threat. This gave England a technological lead over Europe in glass production which would continue for many decades. One such problem and the technical solution was the discolouration of the glass from the fire needed to heat it. When wood is used the glass turned green . Hence forest glass could not be used for window glass or crystal. Neri the Venetian authority on glass in his book of 1612 wrote ” that the fire in a furnace must always be of hard and dry wood taking heed of its smoak, which always hurtheth especially in furnaces where the vessels and pots stand open” and the glass will then receive imperfections and notable foulness”. This important work was translated into English by Sir Christopher Merrett another key figure in the development to fine sparkling champagne and cider and a member of the Royal Society. The solution to this was to cover the pots but this lowered the temperature of the glass in the pots. The discolouration with coal was worse. The solution was increased draught. This could be increased by wind tunnels under the furnace the use of bellows and finally the development of a chimney. The physics of the latter were not understood at the time but it is thought one of the first furnaces to employ a ‘chimney was at Broad Street factory where the furnace was placed under the open spire of the derelict monastic church of the Austin friars. These observations were hinted in a document of 1612 when Sturtevant reported glass had successfully been made with coal at Broad Street factory . The use of a chimney to create a draught was first described by a German alchemist Glauber in German in 1646 and not translated to English until 1651.
An existing chimney on a glass furnace can be seen at Catcliffe near Sheffield.
During Mansell’s control of the glass trade no major changes occurred in the design of bottles. Those of glass being small and thin and fragile or more commonly made of ceramics. . However by 1650 a new bottle appeared, thick, strong and dark. The curious history behind this came clear from a patent dispute. A patent was granted to Colnett in 1661 who claimed he had invented these bottles and could make them in standard sizes before the Civil War and that during the unrest others had started making bottles of a similar nature. This was countered by several people who worked for Digby the next principal in the glass story.
They petitioned that Colnett also worked for Digby and it was he who had invented the new bottle; over 30 years before. Colnett did not defend this, and his patent was transferred to Digby. Sir Kenelm Digby was a polymath of the time. A courtier, scientist, Royalist, dilettante and sailor. The son of one of the Gunpowder Plotters who was hung drawn and quartered! From 1633 to 1636 Digby was a Gresham College and acquainted with Mansell, and on excellent terms with James Howell the manager of Mansell’s Broad Street glassworks. James was injured in a duel and Digby healed his wound with his Powder of Sympathy. (This is in fact nothing more than copper sulphate put at the time was considered the leading edge of medicine and was related to alchemy also practiced by many eminent scientists of the time such as Boyle another founder member of the Royal Society with Digby) . This nascent development and company was interrupted by the Civil War and Digby was imprisoned in Winchester house, which by lucky coincidence, was the site of a longstanding glassworks where he learnt more about glass bottle making. There is a strong possibility that Digby established a furnace at Newnham on Severn close to the heart of Cider and Perry making.
Just North of Newnham is May Hill, famous for Perry production. It is said the best Perry Pears grow in sight of this low but visible hill in Monmouthshire Gloucestershire and Herefordshire.
And Combining Perry with glass bottle making here is a photo of Flakey Bark Perry trees growing on Glasshouse road, so mamed because of a previous glass making factory here.
It could well be Digby’s bottles that Scudamore used in his sparkling cider experiments. Certainly Samuel Pepys mentioned these new bottles in 1663 “Thence to Mr. Rawlinsons and saw some of my new bottles made, with my crest upon them, filled with wine, about five or six dozen”. That Digby invented the new bottles is attested to by the fact that Collnett had his patent declined. Digby was awarded the patent but sadly for him the era of Royal Patents was effectively over after the Restoration. Parliament securing more powers over the Monarch. Quite what the invention was is also unclear. Various sources have pointed to coal fired furnaces operating at higher temperature with wind tunnels and chimneys but this was already being employed by Mansell to make the standard glass. Other suggestions were new formulae of ingredients for the higher temperature glass and certainly these were changed. Digby may well have experimented with these at Gresham College and later at Winchester House. Other suggestions were the uncovered pots ( for increased heat) which gave the new glass a dark near black appearance from smoke particles.
This was soon associated with its strong nature and as colour in a bottle was not a disadvantage compared to a drinking glass, became to represent a sign of quality. Certainly French bottle makers tried to copy the colour. Another advantage of the dark colour of the glass was that it conferred longer aging qualities to the wine by reducing the harmful effects of UV light. Another suggestion was the addition string lip needed to tie the corks down. And finally economics. And finally as per the patent description the standardisation of size.
These bottles were cheaper to make than crystal and window glass with wood fired furnaces. Soon with competition from new glassworks formed since the loss of patent exclusivity the price dropped below the price of other glass and finally below the price of stone or ceramic bottles. Initially being a scare commodity owners had their crest placed on the bottles as Samuel Pepys above. Each bottle the property of the user to be refilled. (contrary to Collnett who wished the manufacturers’ crest on each bottle). Once the price dropped and the bottles became more available, houses and inns ordered them in hundreds if not thousands, without crests, for storage and maturing of wine champagne and cider. Initially made by blowing through a pipe the glass into a globe and then a long neck , ( “when you have gathered some hot glass on the end of a blowing tube and blown it in the form of a large bladder swing the tube with the glass appended to it, beyond your head as if you intend to throw it and the neck will be stretched by this action” ) . The binning of bottles changed the shape from this ‘onion’ to cylindrical by the use of moulds, being easier to lay bottles on the side than neck down, positions needed to keep the cork wet.
Hence the development of the standard wine bottle of today.
Even though these heavy strong bottles are nowadays associated with Champagne the French were slow adopters partly because they preferred still wine. The first coal fuelled dark bottle factory in France was that of Thevenot in Picardy ( the county with coal researves and close to champagne district and Paris ) established in 1709. This was timely with Ruinart prbottling the first sparkling champagne in 1730. ( after the edict of Louis XV in 1728 allowing wine to be transported in bottles. The establishmment of French verre anglais bottle glass industry being one of many industrial espinage and technology transfers that occurred both ways across the English chanel! By 1737 a glassworks close to Paris was making 500,000 bottles per year for the wine industry.