three and a half centuries of bottle manufacture
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THREE AND A HALF CENTURIES OF BOTTLE MANUFACTURE
This paper looks at the development of the bottle glass industry in England. The production of bottles is
considered from both a typological perspective and through the chemical composition of the glass used.
Samples of bottles and bottle production debris from many different production sites have been analysed to
determine their chemical composition. The changes in the social organisation of the industry are discussed in
relation to the changing materials and technologies employed in bottle production.
Glass manufacture has been an important industry inEngland for nearly four centuries. There are threesectors based on the types of glass made: windows,tablewares and bottles. This paper looks at themanufacture of bottles and draws together severalstrands of evidence: documentary sources, thetypological development of bottles and the chemicalanalysis of the glass used to make them. A study ofbottle manufacture provides insights which extendfar beyond this particular industry and contribute tothe idea of a ‘long’ Industrial Revolution. Thetechnologies employed in the glass industry and theorganisation of labour underwent dramatic changesin the 16th and 17th centuries, and again at thebeginning of the 20th century, but during the ‘classic’Industrial Revolution (1760–1830) few significantchanges took place.
The English glass industry was of minor signifi-cance until the late 16th century when continentalglassmakers were brought to England. The early17th century saw the adoption of coal fuel in theindustry; an innovation which continental competi-tors struggled to emulate for the following century orso. Several important glass technologies, such as thecolourless lead crystal glass which was the corner-stone of the tableware industry, were developed inEngland.1 In terms of the sheer quantities of glassmanufactured, however, it was bottle productionthat dominated the English glass industry. Before theearly 17th century few bottles were manufactured,and these were usually thin-walled and wide-mouthed. These bottles appear to have functionedprimarily for serving liquids rather than storing ortransporting them. By the middle of the 17th centurya new type of bottle (almost immediately called theEnglish bottle) appeared which had several featuresthat made it more suitable for the storage andtransport of liquids. This was thick-walled and sorelatively robust for a glass vessel, and it had anarrow neck which enabled the vessel to be sealed.
The English bottle had a major impact on themanufacture and distribution of a range of bev-erages. This paper examines the vexed question ofthe invention of the English bottle and then traceschanges in the industry over the following threecenturies.
THE INVENTION OF THE ‘ENGLISH’ BOTTLE
The origins of the ‘English’ bottle are uncertain andwere contested even in the 17th century.2 The‘English’ bottle was clearly in existence by the middleof the 17th century; in his diary Pepys records, ‘sawsome of my new bottles made, with my crest uponthem, filled with wine, about five or six dozen’.3 Thepractice of applying ‘seals’ clearly shows that the‘English’ bottle was in existence by 1650,4 and it hasoften been assumed that it was invented at about thesame time.5 The c. 1650 origin has found support inthe general absence of ‘English’ bottles from Civil Warand earlier sites. Substantial excavations at PontefractCastle6 and Sandal Castle,7 for example, have failed toproduce ‘English’ bottles. Nevertheless, an earlierorigin for the ‘English’ bottle is accepted by many.8
The earlier date is based on patent applications andother submissions made in 1661.9 A draft Act ofParliament (10 April 1661) awarded a patent for themanufacture of glass bottles to John Colnett (JeanColinet). Petitions were submitted in opposition to thepatent by various glassmakers and the matter inves-tigated by the Attorney General, who concluded that,‘Sir Kenelm Digby first invented the glass bottlesnearly 30 years since, and employed Colnett andothers to make them for him and they have since beenfrequently made by him and also by the petitioners’(Attorney General’s Report, 1662).10 This reportsuggests that the invention of the ‘English’ bottleoccurred c. 1632. This earlier date finds support in theLondon Port Books which list ‘English’ bottles asexports from 1634.11
Some archaeological evidence for early possiblebottle production has been provided by excavations
Industrial Archaeology Review, 34. 1, 37–50, May 2012
# The Association for Industrial Archaeology 2012 DOI: 10.1179/0309072812Z.0000000002
of two glasshouses. Excavations at Kimmeridge, Dorset,which operated between 1618 and 1623, have recoveredfragments of thick glass vessels, including long neckswith a thick ‘string rim’.12 Similar vessel fragments(necks with string rims) have also been recovered fromthe glasshouse at Shinrone, Ireland, which operatedbetween 1620 and 1641.13 The material from both ofthese early glasshouses shows some similarities withearly ‘English’ bottles, in particular the long narrowneck, the thick walls and string rims; however, nonesurvive to show the overall shape of the vessel. Thesevessels appear to have been made from a less stronglycoloured glass compared with bottles made in thesecond half of the 17th century.
BOTTLE DEVELOPMENT: BOTTLE SHAPES AND
The huge number of bottles manufactured and theprogressive changes in their form (Figure 1) havelong been used by archaeologists to date thearchaeological deposits in which they have beenfound.14 The earliest bottles were mouth blown andwere probably made without the use of a mould(‘free blown’). The shaping of the glass usually tookplace in several distinct phases. The first step was thegathering of sufficient glass from the furnace on theend of a blowing iron. This glass was inflated to forma crude oval shape (the parison). The parison was
FIG. 1. Some typical English bottles: a 5 middle 17th century (‘shaft-and-globe’), b 5 late 17th century (‘onion’), c 5
early 18th century (mallet), d 5 late 18th century (cylindrical), e 5 early 19th century (Ricketts), f 5 late 19th century(Codd bottle), g 5 early 20th century (crown cap top). Drawn by Chris Evans.
38 DAVID DUNGWORTH
shaped by rolling it on a smooth stone table (themarver). The parison was then reheated at thefurnace to make it soft enough to be further inflatedto the required size. The shape could be furtheradjusted by stretching the glass or rolling it on themarver. Pincers and other simple tools could be usedto further adjust the shape. The earliest bottles had aglobular body with a long neck (shaft-and-globe,Figure 1a). The bottom was pushed in to provide astable base on which the bottle could stand. By thelate 17th century, bottles were provided with shorternecks and bodies that were more squat (Figure 1b).The early 18th century saw the appearance of shortcylindrical bodies (‘mallet’) that were almost cer-tainly made using moulds (Figure 1c). It is likely thatthe earliest moulds were ‘dip’ moulds (Figure 2).These moulds were simple cylinders that did notopen; instead the glass was introduced, blown to fillthe mould and then withdrawn vertically. Some18th-century bottles with a cylindrical body but witha slightly wider shoulder were almost certainly madein such moulds.15 Inventories for a Bristol glasshouseindicate that iron and brass bottle moulds wereintroduced there in the 1730s.16 Dip moulds
continued to be used in the manufacture of cylind-rical bottles until the middle of the 19th century.17
By the later 18th century the cylindrical bottleswere made rather taller (Figure 1d). The formationof the taller bodies may have been assisted by the useof hinged two-part moulds (Figure 3); however, theearliest illustration of such moulds is 1849.18 HenryRicketts obtained a patent in 1821 for a three-piecemould (Figure 4) which allowed the shaping of the
FIG. 2. The manufacture of free-blown bottles. From left to right: the glassworker inflates the parison (note the simpleone-piece or dip mould at his feet), the kick or pushed in base is formed, the string rim is applied, and the neck finished(from Diderot’s Encyclopaedia).
FIG. 3. A two-piece bottle mould (Pellatt 1849, 103).FIG. 4. The Ricketts patent three-piece mould (UKPatent 4623, 1821).
THREE AND A HALF CENTURIES OF BOTTLE MANUFACTURE 39
neck and shoulders as well as the body of the bottle(Figure 1e). The Ricketts mould allowed the produc-tion of bottles of a uniform size, although capacitywould vary slightly as the glass was still gathered byhand. The Ricketts mould could also be used toemboss words and symbols on the glass; many 19th-century bottles were produced with lettering whichusually indicated the contents of the bottle(Figure 1f). The ‘finish’ (the rim) was still completedby hand, although in the later 19th century a specialpair of tongs was developed which allowed theshaping of a uniform finish.
The development of carbonated drinks in the 19thcentury stimulated changes in bottle design andmanufacture.19 The Codd bottle was one highlysuccessful example of a bottle designed to maintainpressure inside a bottle (Figure 1f). A glass ball (oftenreferred to as a marble) was introduced into the bottleduring manufacture. Once filled with a carbonateddrink, the pressure kept the marble pressed against therim of the bottle and so prevented escape of the gas.
Despite the increased use of moulds, bottlemanufacture through most of the 19th centuryrequired the use of human lung power to inflate theglass. Human labour was also used to gather therequisite amount of molten glass and to ‘finish’the bottle (that is, to complete the neck and mouth).The later 19th century, however, saw the beginningof attempts to mechanise the bottle glass industry.The mechanisation of bottle glass production hasbeen reported in detail20 and only the key points willbe outlined here. The sequence of mechanisation can
be divided into three main phases: the earliestmachines (c. 1880–1905), the Owens and similarautomatic machines (c. 1905–50) and the ISmachines (c. 1950z).
The second half of the 19th century saw a variety ofpatents granted for the manufacture of bottles usingboth moulds and compressed air. The best-known ofthese patents were those awarded to Howard Ashleyin the 1880s for a ‘press-and-blow’ machine.21 Theglass, which was still gathered by hand, was placed ina simple hinged mould. A plunger was used to pressthe glass and form the neck; the plunger was thenremoved and compressed air used to inflate the glassand form the body (Figure 5). The use of the machineallowed a single worker to produce 1560 bottles in thesame time that a traditional team of four wouldproduce 720 bottles.22
The need for the Ashley and similar machines to befed the correct amount of glass by hand was asignificant restriction on their effectiveness. MichaelOwens developed an automatic machine in the lastdecade of the 19th century which both gathered glassand formed this into a bottle.23 The Owens machinehad a series of ‘arms’, each with a parison andfinishing mould. As the machine was rotated, eacharm would be dipped into the molten glass andvacuum suction used to gather the required glass.The machine was rotated to allow the next arm togather glass; while the gathered glass in the first armwas inflated using compressed air to form the bottle(Figure 6). Owens machines required no skilledlabour for their operation and could produce 20
FIG. 5. An Ashley Plank bottle-making machine produced for the Science Museum in 1923.# Science Museum
40 DAVID DUNGWORTH
bottles per minute (or 10,000 bottles in an eight-hourshift). Owens machines were widely used in the firsthalf of the 20th century, although broadly similarmachines (often smaller and cheaper) were developed.24
Many of these machines employed a gob feederwhich could accurately gather the exact quantity ofglass required and deliver it to the formingmachine.25 Machine-made bottles had uniformfinishes that encouraged changes in bottle closure.The two developments that had most impact on themanufacture and use of bottles were the crown capand screw top. The crown was patented in 1892 andcomprised a metal disk with crimped edges whichcould be pushed round the bead rim of the bottle.The screw-top closure started in the late 19thcentury with a thread moulded on the inside of theneck and a corresponding threaded ‘cork’, but in the20th century the external thread and a correspond-ing metal ‘cap’ became the most widely used bottleclosure.
The third development in the mechanisation ofglass bottle production was the IS machine whichwas first patented in 1932 and came to dominate theindustry from the 1950s onwards.26 IS machinesemployed gob feeders to gather the glass and thebasic forming techniques remained the same: parisonand finishing moulds and compressed air. It was thearrangement of the IS machine that was radicallydifferent — the arms did not rotate and each pair ofmoulds operated independently. This arrangementallowed more intense use of each pair of moulds andenabled individual moulds to be serviced while theothers continued to operate.
BOTTLE DEVELOPMENT: RAW MATERIALS AND
Glass bottles have mostly been made using fairlysimple raw materials in order to keep production
costs as low as possible. The principle ingredient forordinary bottles has always been sand which is richin silica (SiO2). Silica has a very high meltingtemperature, however, and so glassmakers havealways added fluxes to lower the melting tempera-ture. Commonly used fluxes have contained one orboth of the alkalis, sodium (Na) and potassium (K).Alkalis have almost always been more expensivethan sand, and so bottle makers have used themsparingly. A glass can be made with just silica andalkali, however, it will not be durable; it will quicklybegin to corrode. The addition of a range of elements(almost any divalent element but especially calcium,Ca) will stabilise the glass and make it durable. Therole of glass stabilisers was not well understood byearly glassmakers, however, the sands and fluxesused were often impure and contained sufficientcalcium to yield a stable glass.
Considered from the point of view of the rawmaterials used, the manufacture of glass bottles canbe divided into four chronological phases. These fourphases have been identified by considering both theavailable documentary evidence as well as modernscientific analyses of historic bottle glass (Table 1).Each source has its own limitations. The documen-tary sources provide varying degrees of detail andthis is most sparse for the early phases. Many of thedocumentary sources replicate each other in waysthat say more about contemporary attitudes tointellectual property rights than they do aboutindustrial practice. The scientific analyses show thefinal composition of the glass but cannot alwaysidentify all of the raw materials (Figures 7–16).Nevertheless, the two sources compliment eachother; in some cases the true significance of onesource only became apparent when compared withthe other source. In most cases the chronologicalphases have been identified through the chemicalcomposition of bottle glass, but the interpretationhas been enriched by a consideration of thedocumentary evidence.
FIG. 6. An Owens bottle-making machine with itsinventor.# Owens-Illinois
TABLE 1. SOURCES OF CHEMICAL ANALYSIS OF BOTTLE
Kimmeridge, Dorset27 1618–23
Haughton Green, Manchester28 1616–53
Silkstone, South Yorkshire29 c.1660–c.1700
Vauxhall, London30 1663–1704
St Thomas Street, Bristol31 c. 1712–c. 1774
Limekiln Lane, Bristol32 c. 1700–c. 1830
Cheese Lane, Bristol33 c. 1700–c. 1800
Bedminster, Bristol34 c. 1750–c. 1820
Nailsea, Somerset35 1788–c. 1850
Portwall Lane, Bristol36 1788–c. 1820
Hightown, West Yorkshire37 c. 1850–c. 1985
THREE AND A HALF CENTURIES OF BOTTLE MANUFACTURE 41
PHASE 1 (c. 1630–c. 1700)
The first phase covers the period from the initialinvention of the English bottle to the end of the 17thcentury during which the main flux in bottle glasswas terrestrial plant ash. The glass is a high-limelow-alkali (HLLA) glass and has the same chemicalcomposition as glass used to manufacture sometablewares38 and most windows.39 The low alumi-nium (Figure 9), high phosphorus (Figure 11) andrelatively low iron (Figure 15) content of early 17th-century bottles suggests that these were made simplywith sand and plant ash. Medieval and early post-medieval sources that describe the manufacture ofthe most utilitarian classes of glass frequentlymention the addition of plant ashes to sand.40 Theplants used were those readily available in forests; inparticular bracken and trees, with most later sourcesstressing the use of trees. The calcium content of theglass (Figure 13) is likely to have been providedalmost entirely from the plant ashes used. The shift
from forested regions to the coalfields at thebeginning of the 17th century would have reducedaccess to traditional plant ashes. The early (1615–20)coal-fired furnace at Wollaton, Nottinghamshire,was reported to have made use of elm, fern and‘straw’ from legumes.41 Christopher Merrett’s 1662translation of Neri’s Art of Glassmaking contains anextended commentary in which he states that, ‘forgreen-glasses in England, they buy all sorts of ashesconfused with one another […] but the best andstrongest of all English ashes, are made of thecommon way thistle’.42 Merrett goes on to list analmost bewildering array of suitable plant asheswhich includes hops, bramble, hawthorn and eventobacco. While not explicitly mentioning bottleproduction, it seems likely that this green glasswould have been used to make bottles. The ironcontent of this glass was sufficiently high to ensurethat it was all green in colour, however, this wasconsistent with the use of these bottles for the storageof wine and beer.
PHASE 2 (c. 1700–c. 1845)
The second phase of bottle glass covers the 18thcentury and the first half of the 19th century. The
FIG. 7. Chronological changes in sodium concentra-tion in English bottle glass (sources: see Table 1). Theincrease in sodium from the mid-19th century reflects theuse of synthetic soda. The horizontal error bars indicate thedating uncertainty (largely based on archaeological contextdates). The vertical error bars indicate the variation inchemical composition for each site and/or phase ofproduction.
FIG. 8. Chronological changes in magnesium concen-tration in English bottle glass (sources: see Table 1). Thelow magnesium concentration in recent glass reflects theswitch to relatively recent pure raw materials.
FIG. 9. Chronological changes in aluminium concen-tration in English bottle concentration in English bottleglass (sources: see Table 1). The low aluminium concentra-tion in recent glass reflects the switch to relatively pure rawmaterials.
FIG. 10. Chronological changes in silicon concentra-tion in English bottle glass (sources: see Table 1).
42 DAVID DUNGWORTH
year 1845 has been selected as a convenient (althoughapproximate) end date, as this was the year that theExcise regulations were repealed. The glass of phase 2shows many similarities with that of phase 1: it is stillessentially a HLLA glass, however, the concentrationof a number of elements show progressive changeswhich indicate significant changes in the raw materialsused.
Through the 18th century a number of the elements(aluminium, phosphorus, iron and strontium) in theglass show gradual change. The decline in thephosphorus concentration (Figure 11) is most easilyexplained as a result of the gradual reduction of theproportion of fresh plant ash.43 Plant ashes were stillutilised in glassmaking during the 18th century, butincreasingly it was the leached ashes (rich in calcium)that were used. Rees’s Cyclopaedia describes commongreen bottle glass as being made ‘almost entirely ofsand, lime, and sometimes clay, alkaline ashes of anykind, as cheapness or convenience direct, and moreespecially of kelp in this country […] [to which] issometimes added the earth remaining from salineashes, after the alkali and salts have been extracted bylixiviation, and in England slags from iron furnaces’.44
While the decline in phosphorus appears to show adecline in the use of traditional plant ashes, thesteady increase in strontium (Figure 16) probablyreflects the increased use of kelp. Kelp is mentionedby many of the 18th- and 19th-century sourcesdiscussed above and it is known to be rich instrontium.45 Recent research into strontium inhistoric glass has focused on the identification ofstrontium in window glass and the confirmation ofkelp as the source of the strontium.46 The strontiumcontent of 18th-century window glass (0.3–0.6wt%SrO) is significantly higher than contemporary bottleglass. This suggests that smaller proportions of kelpwere used in bottle glass compared to window glass.This is supported by the written evidence which oftenrefers to the use of two parts kelp to one part sandfor window glass.47 Very few contemporary bottleglass recipes are quantified but it would seem thatkelp was often only one fifth of the batch.48
The rise in aluminium (Figure 9) could reflectchanges to cheaper (darker) sands, increased use ofblast furnace slag and/or the addition of clay, bricks orsuitable rocks. The relatively substantial increase iniron (Figure 15) is unlikely to be due to the use of blastfurnace slag as such slags at this time typicallycontained only a few wt% of iron.49 Boswell providesdata on the composition of sands used in the bottleindustry during the early 20th century; however, none
FIG. 11. Chronological changes in phosphorus con-centration in English bottle glass (sources: see Table 1).The low phosphorus concentration of recent glass reflectsthe switch away from plant-based alkalis.
FIG. 12. Chronological changes in potassium concen-tration in English bottle glass (sources: see Table 1). Thehigh potassium content of early glass reflects the use ofterrestrial plant ashes.
FIG. 13. Chronological changes in calcium concentra-tion in English bottle glass (sources: see Table 1).
FIG. 14. Chronological changes in titanium concentra-tion in English bottle glass (sources: see Table 1).
THREE AND A HALF CENTURIES OF BOTTLE MANUFACTURE 43
of these contain enough iron to give rise to the ironconcentrations seen by the end of the 18th century.50
There is a correlation between aluminium and ironcontent, which could reflect the use of increasedquantities of clay and/or brick.
While the change in aluminium, phosphorus, ironand strontium content of the glass can be linked to thelimited documentary sources, the chemical analysis ofsamples of bottle glass and glassworking debris fromdated archaeological contexts shows how glassmakersprogressively changed their raw materials. The moststriking aspect of the changes at this time are the factthat the major components (silicon and calcium) showvirtually no change while a range of minor and traceelements either increase or decrease. The changes incomposition are certainly due to a complete change inall materials, except sand; however these changeswere achieved gradually and without making exces-sive changes in the overall character of the glass.Between 1700 and 1800 the iron content rose from1.8 to 2.4wt% Fe2O3, that is, 0.006wt% per year.Change at such a pace would be imperceptible at thescale of a single working lifetime. The most attractiveexplanation for this continuous but gradual change isthat glassmakers were constantly exploring the limitsof their glass. They had a range of ingredientsavailable and probably inherited a standard recipefrom earlier glassworkers. Initially, glassworkersprobably added small amounts of a new material,for example soapmakers’ waste. They would havejudged the use of the new material against the physicalproperties of the glass rather than its chemicalcomposition. If the glass could be easily melted and,once molten, could be inflated and keep the requiredshape, then it would be judged successful. Anadditional consideration would probably have beenthe durability of the finished glass. Economic con-siderations provided the motive force to use, as muchas possible, cheaper ingredients.51 The data outlinedabove is consistent with a workforce that was attunedto its basic medium and prepared to explore itsmaterial limits through trial and error.
The raw materials used in bottle glass manufacturewere also affected by the taxation on glass.52 Onewitness to the 1835 Commissioners of Excise reportsbeing prosecuted for using a particular raw material,while others reported that they avoided the use of arange of materials ‘solely by the dread of theconstruction which might be put upon a doubtfulclause of an excise statute’.53 Nevertheless, a casualexamination of early 19th-century bottles shows thata small proportion is very pale green. Contemporarysources provide little information on the materialsused for the manufacture of pale green bottles before1845. The Excise laws prevented the use of finematerials in order to maintain a distinction betweencommon bottle glass and flint glass (used forpharmaceutical phials and the like) as these weretaxed at very different rates. Cookson implies that hewas producing some pale bottles using cullet (wasteglass) from window glass manufacture but that hehad been prosecuted for it.54
PHASE 3 (c. 1845–c. 1918)
The bottle glass of phase 3 is some of the mostchemically varied, but there are few detailed doc-umentary sources for its manufacture and relativelyfew samples of glass of this period have been analysed.The repeal of the Excise Laws in 1845 had freed thebottle industry from the requirement to use only thecoarsest materials. Glassmakers were free to chooseany materials which suited their purposes. The bottleglass of this period tends to fall into one of two types:a dark green or brown HLLA glass which continuesthe tradition of phase 2 HLLA glass, and a pale greensoda-lime-silica (SLS) glass which shows some simila-rities with contemporary window glass. Both types ofglass contain little or no phosphorus, potassium orstrontium which indicates very little use of plant ashes(terrestrial or marine). The HLLA glass containsincreased levels of sodium (but very low levels ofpotassium) compared to phase 2, suggesting that itwas fluxed with a small proportion of Leblanc soda.
FIG. 15. Chronological changes in iron concentrationin English bottle glass (sources: see Table 1). The low ironcontent of recent glass reflects the switch to relatively purematerials and the desire for colourless bottles.
FIG. 16. Chronological changes in strontium concen-tration in English bottle Glass (sources: see Table 1). Thehigher strontium content of 18th-century glass is probablydue to the use of seaweed ash (kelp).
44 DAVID DUNGWORTH
The SLS glass has a much lower iron content than theHLLA glass and was probably made using betterquality raw materials, including low-iron sands. Thesematerials were considerably more expensive and theiruse was restricted to the manufacture of a limitedrange of bottles, in particular the emerging range ofbottles designed to hold carbonated drinks. While thedark green or brown colour of conventional HLLAglass (due to its high iron content) was beneficial forthe storage of many alcoholic drinks, the newcarbonated drinks industry had new requirements.55
These drinks were commonly flavoured and colouredwith fruit juices; the marketing of these drinks madeuse of their colours and so the colour had to be visibleto the customer. This visibility was only possiblewhere the glass was not strongly coloured. The changeto purer but more expensive ingredients was aligned,therefore, to an increased appreciation of the con-sumer, their preferences and their willingness to pay apremium.
PHASE 4 (c. 1918 onwards)
The final phase covers the period since the glassbottle industry mechanised. The chemical analysis ofglass bottle manufactured since mechanisation showsthat all are SLS glass and mostly with very low ironcontents which would result in a colourless glass.56
The impact of mechanisation on the sorts ofmaterials used in the industry is well known fromdocumentary sources.57 The most important con-sideration in making glass is its viscosity: it must besufficiently fluid during gathering and inflating toproduce the desired shape, but must become suffi-ciently solid on cooling to retain this shape. Theviscosity of glass changes dramatically with tempera-ture; it becomes increasingly fluid at high tempera-tures. The viscosity at any given temperature isdetermined primarily by the composition of the glass.
In general, increasing the proportion of alkali andother fluxes will make a glass more fluid at any giventemperature. When bottles were formed using lungpower alone, the glass viscosity was a relativelyunimportant consideration. The human factor inglass forming was a boon where many of the rawmaterials were recycled. The variable nature of theraw materials meant that the glass could behave inslightly different ways on different days of the week.The individual skilled worker could, however, adaptthemselves to the inevitable variations in thebehaviour of the molten glass. The development ofmechanical forming inevitably brought a need forglass with different heat-viscosity properties. Earlymachines, such as the Ashley plank, could beoperated using glass of essentially the same characteras that made using lung power alone; however, latermachines, in particular the Owens machine requiredglass which would set more slowly.58 It was quicklyfound that the most suitable glass composition was asoda-lime-silica glass. Typically this would contain17wt% soda (Na2O), 9% lime (CaO) and 73% silica(SiO2), with the balance (1%) largely provided byalumina (Al2O3). Subsequent developments aredifficult to trace through the analysis of archaeolo-gical samples due to the rather imprecise nature ofcontext dating. Nevertheless, data on 20th-centurybottle glass can be found which suggests that, sincemechanisation the proportion of silica has remainedunchanged, while lime has been slightly increasedand soda decreased (Figure 17).59
Some green glass was produced with elevatedlevels of iron, although it is not certain whether thiswas deliberately added as a distinct colourant orsimply made use of cheaper (darker) sands. Smrcek60
identified the deliberate use of chromium in place ofiron to produce green glass from the 1960s.61 It islikely that, as bottle-making factories became larger,it was cheaper to secure a single source of low-iron
FIG. 17. Documented changes in the composition of UK-produced bottle glass in the 20th century.
THREE AND A HALF CENTURIES OF BOTTLE MANUFACTURE 45
sand to be used for all bottles but deliberately addsuitable colorants (such as chromium) to particularbatches depending on customer requirements.
There is limited data available on the quantities ofbottle produced in England over the last threecenturies. For almost the first century of productionthere is no indication of the rate of production.Houghton’s 1695 Essays reveal that some 40 glass-houses were engaged in bottle manufacture with anannual output of 240,000 dozens, or 2.88 millionbottles.62 For most of the 18th century there are noreliable sources, however, the records of the ExciseDuty indicate that the period 1775–1835 saw annualproduction of 10 to 20 million bottles from virtuallythe same number of glasshouses recorded byHoughton at the end of the 17th century.63 Themechanisation of the industry saw an incredible leapin production (Figure 18). In 1913, 280 millioncontainers (including bottles) were produced eachyear and by 1965 this had increased to five billion ayear.64
There is slender evidence for the economic basis ofearly bottle manufacture. Angerstein’s description ofglass bottle manufacture in Bristol in 1754 includesa detailed account with some useful economicinformation.65 Nevertheless, a careful analysis ofhis figures suggests that they do not tell the wholestory. Angerstein says that each furnace has fourcrucibles and that each will hold 1cwt (50.8kg) ofbatch (raw materials). He does not say how long ittakes to melt and then work this much glass, butreference to later practice suggests that this wouldtake 24–36 hours. In a typical week, therefore, theglasshouse would melt 16cwt (0.8tonnes) of glass.Angerstein reports that, for each cwt of glass melted,a tax of 2s 4d was paid which would give a weekly
tax bill of £1 17s 4d. This glass was used to produce240 dozen bottles which were sold for 20d per dozengiving a weekly income of £20. The production of240 dozen bottles by four teams in a week seems lowcompared to William Powell’s suggestion that oneteam could produce 60 dozens in a day.66 Themanufacture of 240 dozen bottles from 0.8t of glasswould produce bottles with an average weight of0.25kg which is very low compared to typical bottlesof the period which weigh 1kg.67
Angerstein provides information on the labouremployed including their rates of pay from which itcan be seen that each crucible was worked by a teamof five. Within each team the weekly pay varied from4s to 25s per man and the total weekly wage bill was£14 8s 0d. Labour costs thus appear to haverepresented almost three-quarters of the value of thebottles produced. The only further informationprovided on the costs of the raw materials used isthe coal which was consumed at a rate of 1.5–2 tonsper day and cost 7d per sack (of three bushels). Theweekly fuel bill can therefore be estimated between £28s 7d and £3 5s 4d. The identified weekly expendituretherefore amounted to £18 13s 11d–£20 5s 8d againstan income of £20. Taking these figures at face valuesuggests that the raw materials must of necessity havecost almost nothing, however, it is difficult to see howthe glasshouse described by Angerstein could makeany kind of profit.
SOCIAL ORGANISATION AND STATUS OF
LABOUR IN THE GLASS BOTTLE INDUSTRY
The bottle glass industry has undergone significantchanges in the scale of production and the technol-ogies employed; these have both had significantimpacts on the social organisation and status of theworkforce. The early post-medieval glass industrywas characterised by an integration of labour and
FIG. 18. Numbers of bottles produced per year.
46 DAVID DUNGWORTH
capital. What little evidence there is for theorganisation of the medieval industry suggests thatindividual glasshouses were largely owned and runby yeoman farmers.68 It is surmised that, for some atleast, glassmaking was a seasonal activity which wasintegrated into the changing activities of the agri-cultural year. This pattern of what was effectively apart-time and owner-operated industry appears tohave persisted for at least some glasshouses until atleast the late 17th century. An unnamed glassmakerfailed to appear at the Wakefield Quarter Sessionsbecause he ‘was at plow’.69 The arrival of Frenchglassmakers in the 16th century brought men whoregarded themselves as minor nobility, gentil-shommes verriers.70 Glassmaking families in bothNormandy and Lorraine had been granted wide-ranging privileges during the medieval period. Theindependence of these men is well illustrated by adispute between a family of Norman glassmakersand English glassmakers. The Frenchmen had beeninvited to England by Jean Carre who had beengranted a patent for glassmaking in 1567.71 One ofthe conditions imposed on Carre was that he mustensure the training of English workers. Unfortunately,the contract between Carre and the Frenchmen didnot bind them to provide this training. When a partyof Englishmen arrived at the glasshouse of Peter andJohn Bungar, a fight ensued in which one of theBungars used a blowing iron with ‘hotte glass metalapon yt’ as a weapon.72 The independent spirit ofmany glassmakers continued into the 18th century:
Yesterday a press gang went into the glass-house in White Fryars to press some of the menat work there, but they were no sooner got inbut the (molten) metal was flung about ’em,and happy was he that could get out first, andin hurrying out they ran over their officer, whowas almost scalded to death.73
The financial rewards of glassmaking appear to havebeen considerable. Although the French glassmakerswho arrived in England in the late 16th centurysometimes pleaded poverty, ‘they were poor only incomparison with rich merchants or the gentry onwhose estates they settled’.74 The glassworkers’ payreflected their skill and status: in the mid-18thcentury the glassworking chair would be headed bya man who would earn up to 25s per week,75
compared to craftsmen in the building trade whowould typically earn 12s per week.76 Angerstein’sfigures for a Bristol glasshouse suggest that labourwas the single most expensive item in the manufac-ture of bottle glass. As a group, glassworkersmaintained a position in society somewhat ahead ofmost industrial workers. In 1738 a parade was heldin Bristol of representatives of most trades in honourof a visit by the Prince and Princess of Wales. Theglass makers ‘went first dressed in white Holland
shirts, on horseback, some with swords, others withcrowns and sceptres in their hands made of glass’.77
A shift in the status and labour relations ofglassworkers may have begun as early as thebeginning of the 18th century. Seventeenth-centuryglasshouses were established, owned and worked byan individual or family.78 Many of the glassworkerscan be identified by their surnames as descendants ofthe French glassmakers who emigrated to England inthe late 16th century. These men were often acutelyaware of their gentilshommes verriers lineage, andmost 17th-century glasshouses were owned by menwho took apprentices. This practice continued atsome glasshouses into the 18th century; however,new glasshouses tended to be established by partner-ships which often included no more than one actualglassmaker. The Hoopers glasshouse on Avon Street,Bristol, was set up in 1720 by a partnership whichincluded one glassmaker, one glasshouse pot maker,a barber surgeon, an innkeeper, a maltster, twomarines, a soapboiler, a sugar baker, three merchantsand five hoopers.79 Some of the partners probablyregarded glassmaking as complimentary to theirexisting business interests either something theyproduced could be used in a glasshouse, or viceversa — vertical integration.
The interest of soapmakers in several Bristolglasshouses80 is unlikely to be a coincidence.Indeed, 17th-century regulations in Bristol preventedsoapmakers from disposing of their waste in theriver, but glasshouses provided the opportunity todispose of their waste at a profit. Another importantgroup of investors were those with existing commit-ments in the manufacture and sale of alcoholicdrinks. Such investors had an interest in seekingpreferential terms for the bottles that were increas-ingly used for the storage and transport of a range ofbeverages. Nevertheless, some of the new investors inthe glass industry approached their ventures from apurely capitalistic point of view with little directinterest in the working of the glasshouse or the fateof its products. The change in the background andinterests of the owners of glasshouses can perhaps belinked to technological changes in glass manufacture.By the end of the 17th century the large conicalbuildings used to contain glass furnaces werebecoming increasingly popular.81 These large build-ings would have required considerably more capitalexpenditure compared to earlier glasshouses.
The 18th-century influx of investors and ownerswho were not themselves skilled in glass manufacturecan be identified from contemporary records, such ascourt cases, sales, and so on.82 Less information isavailable on the relationship between the new breedof owners and those who laboured in the glass-houses, although written sources do provide a fewhints. In 1743 the Newcastle Journal advertised thesale of a glasshouse ‘with a complete set of tools andworkmen’.83 While there can be no suggestion that
THREE AND A HALF CENTURIES OF BOTTLE MANUFACTURE 47
workers were legally tied to this particular glass-house, the advert indicates that a change of owner-ship was divorced from a change of workforce. Anexample of poor relations between owners andworkers can be seen in the prosecution of JamesWatkins in 1752. Felix Farley’s Bristol Journal of 15August reports that Watkins, who had worked atThomas Warren’s glasshouse in St Thomas Street,was arrested for the theft of a brass bottle mould;however, in the same newspaper (16 September) itwas reported that Watkins was acquitted.84
Glassworkers may have shifted from owner-work-ers to wage-labourers, but they maintained a degreeof control of their own work and workplace that isseen in few other industries. It was common formanufacture to be measured and rewarded by theteam rather than the individual. Powell describedbottles as made by a ‘a set of hands’ or team of fivecomprising a ‘gatherer’, a ‘blower’, a ‘wetter off’, a‘workman’, and a ‘boy’.85 It was usual for the teamto be required to produce a specific number of bottleswithin a shift, and they were paid for these bottlesrather than the time it took them to produce them.More bottles could often be made if there was timeand glass available and these would be paid at anadditional rate. In some cases the senior man in theteam was given the entire sum of money due and hethen decided how it should be subdivided betweenthe different members of the team. Recruitmentwithin the workforce was limited to sons ofglassworkers and required the completion of longapprenticeships. The power of the glassworkers canbe seen in the comment made by one 19th-centuryglasshouse owner following the repeal of the exciseLaws, ‘we have exchanged the excise for a muchseverer taskmaster, videlicet, our own men’.86 Suchsentiments no doubt helped push owners to formtrade associations. Indeed, the Glass BottleManufacturers of Yorkshire Trade Association wasformed to ‘unite ourselves together for our commongood and the benefit of the trade generally; towithstand the aggression of our men’.87 The work-force were opposed to the mechanisation of theirindustry and it has been argued that ‘the failure ofthe Ashley Machine Company was largely due tounion opposition’.88 Mechanisation may have beenattractive to owners as a way of reducing costs,89
however, the draw of de-skilling the workers, and soreducing their power, should not be underestimated.
The so-called English bottle comprised a robustvessel with a narrow neck. This contrasted withearlier bottles and allowed the storage and transportof liquids, especially alcoholic drinks. The Englishbottle was quickly adopted and its production helpedEngland to dominate the glass industry for centuriesafterwards.
The bottles themselves as well as the raw materialsand technologies used in their manufacture and theorganisation of the workers who made them have allundergone extensive change in the centuries since theEnglish bottle first made its appearance. Early bottleswere made simply using sand and plant ashes. Theywere generally made in small glasshouses by menwho owned and worked in the glasshouses. Thebottles themselves were entirely produced using lungpower and fabricated by hand with simple tools. The18th century saw gradual changes in both therelationship between the workers and their productsand in the nature of the products themselves.Increasingly, the glasshouses were larger and moreheavily capitalised with more separation of ownersand workforce. The recipes used to make the glassgradually became more ‘industrial’ with ever-increas-ing proportions of low-value materials, especiallywaste materials from other industries. The bottleswere still shaped using human lung power, butincreasing use was made of moulds to producestandardised shapes and sizes of bottle. Although theworkforce no longer owned the plant and premises,it remained one of the most powerful and autono-mous industrial groups.
The mechanisation of the bottle glass productionthat took place at the beginning of the 20th centurysaw far-reaching changes to the industry. Whilemechanisation allowed an increase in the productionof bottles, it is also possible to view mechanisation asa strategy employed by capitalists to de-skill and de-power their workforce. Despite the gradual erosionof the status of glassworkers, in the 19th centuryglassblowers were still well paid and well organised.The labour costs formed a relatively high proportionof the overall production costs for most types of glassproduct. Machines offered the possibility of remov-ing the reliance on a workforce that was oftenviewed as difficult. Contemporary cost analysisshows that machine-made bottles could be mademore cheaply than mouth-blown ones, however,although savings were made in labour costs, materialcosts actually rose. The machines were not able todeal effectively with the traditional high-lime low-alkali (HLLA) glass that was used in the productionof mouth-blown bottles. The only glass that wouldwork with the machines was a soda-lime silica glassmade using relatively pure and expensive ingredients.
I would like to thank the many colleagues without whomthe research for this paper would not have been possible.My thanks are due to the archaeologists who provided thenumerous samples of bottle glass and glassworking wastefor chemical analysis that form the basis of much of thispaper (Bruce Williams, Bob Jones, Anne Finney, RegJackson, Kieron Tyler, Hugh Willmott and MichaelChapman). The research would have not been possiblewithout the assistance of fellow researchers (Eleanor
48 DAVID DUNGWORTH
Blakelock, Caroline Jackson, Cath Mortimer, VictoriaLucas and Carlotta Gardner) who completed the chemicalanalysis of material from many of the sites used in thispaper.
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2. Charleston, R.J., English Glass and the Glass Used inEngland, c.400–1940 (London: Allen and Unwin, 1984),93–95; Godfrey, E.S., The Development of EnglishGlassmaking 1560–1640 (Chapel Hill: University ofNorth Carolina Press, 1975), 228–32.
3. Wheatley, H.B. (ed.), The Diary of Samuel Pepys(London: George Bell and Sons, 1893), Friday, 23October 1663.
4. Egan, G., ‘London — Axis of the Commonwealth?’, inG. Egan and R. L. Michael (eds), Old and New Worlds(Oxford: Oxbow Books, 1999), 61–71.
5. Hume, I.N., ‘The Glass Wine Bottle in Colonial Virginia’,Journal of Glass Studies, 3 (1961), 93; Willmott, H., EarlyPost-Medieval Vessel Glass in England (London: Councilfor British Archaeology, 2002), 86.
6. Roberts, I., Pontefract Castle: Archaeological Excavations1982–86 (Leeds: West Yorkshire Archaeological Services,2002).
7. Mayes, P. and L.A.S. Butler, Sandel Caste Excavations1964–1973: A Detailed Archaeological Report (Wake-field: Wakefield Historical Publications, 1983).
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9. Godfrey, ref. 2, 228–9; Phelps, M., ShinroneGlasshouse, Co. Offaly, Ireland. Analysis of 17th-Century Glass Vessel Fragments (Portsmouth: EnglishHeritage, 2010).
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15. Jones, O.R., Cylindrical English Wine and BeerBottles 1735–1850 (Quebec, Parks Canada, 1986), 84.
17. Ibid., 86.
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Newcomen Society, 73 (2001–2), 1–31; English, S.,‘The Ashley Bottle Machine’, Journal of the Society ofGlass Technology, 7 (1923), 324–33; Meigh, E., ‘TheDevelopment of the Automatic Glass Bottle Machine.A Story of Some Pioneers’, Glass Technology, 1(1960), 25–54; Moody, B.E., ‘A Century ofMechanical Bottle Making’, Glass Technology, 26(1985), 108–24; Moorshead, T.C., ‘The Glass BottleIndustry and Future Developments’, Journal of theSociety for Glass Technology, 9 (1925), 282–315;Weedon, C.E., ‘The Glass Container Industry 1916–1976’, Glass Technology, 17 (1976), 165–81.
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27. Crossley, ref. 12.
28. Vose, R.H., Glass (Collins, 1980).
29. Dungworth, D. and Cromwell, T., ‘Glass and PotteryManufacture at Silkstone, Yorkshire’, Post-MedievalArchaeology, 40 (2006), 160–90; Dungworth, D.,Scientific Examination of Glass and GlassworkingMaterials from Silkstone Yorkshire (Portsmouth:English Heritage, 2003).
30. Tyler, K. and H. Willmott, Excavations at John Baker’sVauxhall Glasshouse (Museum of London, 2005);Dungworth, D., Vauxhall, London. The ScientificExamination of Glass and Glassworking Materials fromthe Late Seventeenth-Century Glasshouse (Portsmouth:English Heritage, 2006).
31. Dungworth, D., St Thomas St, Bristol: Examinationand Analysis of Glass and Glassworking Debris(Portsmouth: English Heritage, 2007).
32. Dungworth, D., Investigation of 18th-Century Glassand Glassworking Waste from Limekiln Lane, Bristol(Portsmouth: English Heritage, 2005).
33. Dungworth, D. and C. Mortimer, Examination ofGlassworking Materials from Cheese Lane, Bristol.(English Heritage, 2005); Jackson, R., ‘Excavations on theSite of Sir Abraham Elton’s Glassworks, Cheese Lane,Bristol’, Post-Medieval Archaeology, 39 (2005), 92–132.
34. Blakelock, E., Bedminster Glue Factory, Bristol:Examination and analysis of glass and glassworkingdebris (Portsmouth: English Heritage, 2007).
35. Hatton, G., Scientific Examination of Glass and GlassWorking Materials from Nailsea, Avon (Portsmouth:English Heritage, 2004); Smith, A.F., The NailseaGlassworks, Nailsea, North Somerset (Bristol: AvonArchaeological Unit, 2004).
36. Caroline Jackson personal communication.
37. Gardner, C., Hightown, Castleford Yorkshire. AnAssessment of Glass Waste (Portsmouth: EnglishHeritage, 2009). Lucas, V., Hightown, Castleford,West Yorkshire: An Assessment of Bottle Glass fromthe Hightown Glasshouse (Portsmouth: EnglishHeritage, 2010).
38. Dungworth and Cromwell, ref., 29.
39. Dungworth, D., ‘The value of historic window glass’,The Historic Environment, 2 (2011), 19–46.
40. Hawthorne, J. G. and C. S. Smith, Theophilus OnDivers Arts (New York: Dover, 1979). Hoover, H. C.and Hoover, L. H. (eds), Georgius Agricola. De Re
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Metallica (New York: Dover, 1950). Smith, C. S. andGnudi, M.T., The Pirotechnia of VannoccioBiringuccio (New York: Dover, 1990). Welch, C.M.,‘Glass-making in Wolseley, Staffordshire’, Post-Medieval Archaeology, 31 (1997), 1–60.
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43. Turner, W.E.S., ‘Studies in Ancient Glasses andGlassmaking Processes. Part V. Raw Materials andMelting Processes’, Journal of the Society for GlassTechnology, 40 (1956), 277–300.
44. Cossons, N. (ed.), Rees’s Manufacturing Industry(1819–20), 3 (Newton Abbott: David and Charles,1972), 85.
45. Dungworth, D., P. Degryse and J. Schneider, ‘Kelp inHistoric Glass: The Application of Strontium IsotopeAnalysis’, in P. Degryse, J. Henderson and G. Hodgins(eds), Isotopes in Vitreous Materials (Leuven: LeuvenUniversity Press, 2009), 113–30.
46. Dungworth, ref. 39; Dungworth, D., ‘Innovations in the17th-Century Glass Industry: The Introduction of Kelp(Seaweed) Ash in Britain’, in S. Lagabrielle and M.Philippe (eds), Les Innovations Verrieres et Leur Devenir,Les Cahiers de Verre et Histoire No. 2 (forthcoming).
47. Parkes, S., Chemical Essays (London: Baldwin,Cradock and Joy, 1823), 192.
48. Muspratt, S., Chemistry. Theoretical, Practical andAnalytical (Glasgow: Mackenzie, 1860); Ure, A., ADictionary of Arts, Manufactures and Mines (NewYork: Appleton, 1844).
49. Tylecote, R.F., A History of Metallurgy (London: TheInstitute of Materials, 2nd edn, 1992), 126.
50. Boswell, P.G.H., A Memoir on British Resources ofSands and Rocks used in Glass-Making (London:Longmans, Green and Co., 1918).
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54. Ibid., 100.55. Talbot, ref. 19.56. Gardner, ref. 37; Lucas, ref. 37.57. Cable, ref. 42; Turner, W.E.S., ‘The Composition of Glass
Suitable for Use with Automatic Machines’, Journal of theSociety of Glass Technology, 10 (1926), 80–94.
58. Turner, ref. 57.59. Race, S., ‘Glass Container Manufacturing: From the
Past into the Future’, Glass Technology, 21 (1980), 6–25; Smrcek, A., ‘Evolution of the Compositions ofCommercial Glasses 1830 to 1990. Part II. ContainerGlass’, Glass Science Technology, 78 (2005), 230–44.
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(Leicester: Leicester University Press, 1967), 108.69. Ashurst, D., The History of South Yorkshire Glass
(Sheffield: Collis, 1992).70. Philippe, M., Naissance de la Verrerie Moderne, XIIe–
XVIe siecles (Turnhout: Brepols, 1998).71. Godfrey, ref. 2, 16.72. Ibid., 24.73. 1732 Whitehall Evening Post, quoted in Douglas and
Frank, ref. 62, 17.74. Godfrey, ref. 2, 186.75. Berg and Berg, ref. 65, 130.76. Weedon, C.E., ‘The Bristol Glass Industry: Its Rise and
Decline’, Glass Technology, 24 (1983), 249.77. Ibid., 250.78. Dungworth and Cromwell, ref. 29.79. Witt, C., C. Weedon and A.P. Schwind, Bristol Glass
(Bristol: City of Bristol Museum and Art Gallery, 1984), 51.80. Ibid., 49–53.81. Crossley, D., ‘The Archaeology of the Coal-Fuelled
Glass Industry in Britain’, Archaeological Journal, 160(2003), 160–99.
82. Buckley, F., Old English Glass Houses (Sheffield:Society of Glass Technology, 2003).
83. Ibid., 49.84. Ibid., 88.85. Powell et al., ref. 51, 84.86. Turner, W.E.S., ‘The British Glass Industry: Its
Development and Outlook’, Journal of the Society ofGlass Technology, 6 (1922), 129.
87. Bagley, S.B., ‘Corporate Efforts in the Glass Industry’,Journal of the Society of Glass Technology, 25 (1941), 111.
88. Meigh, ref. 20, 42.89. Meigh, ref. 20, table 4.
NOTES ON CONTRIBUTOR
DAVID DUNGWORTH has a degree in Ancient Historyand Archaeology from Birmingham University and adoctorate in archaeological science from DurhamUniversity. He has a keen interest in the scientificstudy of materials and residues produced by manydifferent high-temperature industries from prehistoryto the 20th century. He has worked as a materialsscientist with English Heritage for 12 years.
Correspondence to: David Dungworth, EnglishHeritage, Fort Cumberland, Portsmouth Po4 9LD,UK. Email: david.dungworth@english heritage.org.uk
50 DAVID DUNGWORTH